Evaluation And Risk Assessment For Persistent Postsurgical Pain After Breast Surgery: A Prospective Cohort Study (Breast CAncer Surgery Postsurgical Pain)
Conditions: Breast Cancer, Chronic Pain, Acute Pain, Depression, Anxiety
Sponsor: KK Women's and Children's Hospital

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STUDY PROTOCOL 
 
 
Evaluation And Risk Assessment For Persistent Postsurgical Pain 
After Breast Surgery:  A Prospective Cohort Study (Breast CAncer 
surgery Postsurgical Pain (B-CAPP)) 
 
 
 
 
 
CIRB PROTOCOL NUMBER:  
2017/2805 
 
PROTOCOLVERSION: 1.0 
 
PROTOCOL DATE:  
18 Jan 2018 
 
PRINCIPAL INVESTIGATORS:  
A/Prof Sng Ban Leong, Senior Consultant, KK Women's and Children's Hospital 
(KKH) 
Prof Ashraf S. Habib, Professor of Anesthesiology with Tenure, Duke University 
 
 
 
 
 
 
 
*Also refer to page 14 on the statistical and analytical plan. 
 
 

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Table of Contents 
1. 
BACKGROUND AND RATIONALE................................................................................................. 4 
2. 
HYPOTHESIS AND OBJECTIVES ................................................................................................. 6 
3. 
EXPECTED RIKS AND BENEFITS ................................................................................................. 7 
4. 
STUDY POPULATION .................................................................................................................. 7 
4.1. 
LIST THE NUMBER AND NATURE OF SUBJECTS TO BE ENROLLED. ................................................................................ 7 
4.2. 
CRITERIA FOR RECRUITMENT AND RECRUITMENT PROCESS ...................................................................................... 7 
4.3. 
INCLUSION CRITERIA .............................................................................................................................................. 8 
4.4. 
EXCLUSION CRITERIA .............................................................................................................................................. 8 
5. 
STUDY DESIGN AND PROCEDURES/METHODOLOGY ................................................................. 8 
6. 
SAFETY MEASUREMENTS.......................................................................................................... 11 
6.1. 
DEFINITIONS ........................................................................................................................................................ 11 
6.2. 
COLLECTING, RECORDING AND REPORTING OF ADVERSE EVENTS AND SERIOUS ADVERSE EVENTS TO CIRB ............ 11 
6.3. 
SAFETY MONITORING PLAN ................................................................................................................................... 12 
6.4. 
COMPLAINT HANDLING .......................................................................................................................................... 12 
7. 
DATA ANALYSIS........................................................................................................................ 13 
7.1. 
DATA QUALITY ASSURANCE ................................................................................................................................... 13 
7.2. 
DATA ENTRY AND STORAGE .................................................................................................................................. 13 
8. 
SAMPLE SIZE AND STATISTICAL METHODS ............................................................................. 14 
8.1. 
DETERMINATION OF SAMPLE SIZE ......................................................................................................................... 14 
8.2. 
STATISTICAL AND ANALYTICAL PLANS .................................................................................................................... 14 
9. 
DIRECT ACCESS TO SOURCE DATA/DOCUMENTS .................................................................... 15 
10. QUALITY CONTROL AND QUALITY ASSURANCE ...................................................................... 15 
11. ETHICAL CONSIDERATIONS ..................................................................................................... 15 
11.1. 
INFORMED CONSENT ............................................................................................................................................. 15 
11.2. 
CONFIDENTIALITY OF DATA AND PATIENT RECORDS .............................................................................................. 16 
12. PUBLICATIONS ......................................................................................................................... 16 
13. RETENTION OF STUDY DOCUMENTS ........................................................................................ 16 
14. FUNDING AND INSURANCE ...................................................................................................... 16 
 
 
 
 
 

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PROTOCOL SIGNATURE PAGE 
 
 
 
Protocol Title: Evaluation And Risk Assessment For Persistent Postsurgical Pain After Breast Surgery: A 
Prospective Cohort Study (Breast CAncer surgery Postsurgical Pain (B-CAPP)) 
 
Protocol Number: BCAPP01 
 
 
Protocol Version/ Date: 1.0, dated 18 Jan 2018 
 
 
Sponsor Name: Duke-NUS/SingHealth Collaborative Funding 
 
 
 
Declaration of Investigator 
 
I confirm that I have read the above-mentioned protocol and its attachments. I agree to conduct the 
described trial in compliance with all stipulations of the protocol, regulations and ICH E6 Guideline for 
Good Clinical Practice (GCP).  
 
  
 
 
Principal Investigator Name:  A/Prof Sng Ban Leong 
                                                            
 
Principal Investigator Signature:  _______________________________________ 
                                                            
 
Date:  __________________________________________ 
                                                            
 
 
Principal Investigator Name:  Prof Ashraf Habib 
                                                            
 
Principal Investigator Signature:  _______________________________________ 
                                                            
 
Date:  __________________________________________ 
 
 
 

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1. 
BACKGROUND AND RATIONALE 
 
Impact of Persistent Pain after Breast Cancer Surgery 
Breast cancer is a leading cancer diagnosis among women worldwide, with more than 1 million 
new cases per year. It costs more than $100 billion annually in direct medical costs and lost 
productivity in the United States. Persistent pain following breast cancer surgery has been 
recognized as a major humanitarian and socioeconomic burden, affecting about 50% of patients 
after lumpectomy and mastectomy leading to chronic physical disability and psychological 
distress (1, 2). 
The pathogenesis of breast cancer surgery-related pain is likely multifactorial, and risk factors 
such as age, body mass index and genetic predisposition have been demonstrated to affect 
persistent pain development (3-5). Despite a number of studies investigating risk factors, almost 
all information originated from single centre studies and often focus on only few elements, 
rather than the full continuum of perioperative care. Additionally, surgical approaches, adjuvant 
therapy and analgesic regimens have changed in recent years therefore limiting the interpretation 
of previous studies, yet tools to identify those at high-risk and preventive interventions are still 
lacking. Here we propose to investigate the risk factors related to persistent postsurgical pain in 
breast cancer patients, and to develop a prediction model that could serve as a screening tool for 
patients at high-risk of developing persistent postsurgical pain. 
 
Pain Vulnerability and Psychological Vulnerability May Affect the Risk of Postsurgical 
Pain 
Psychological Vulnerability: Psychological vulnerability, including depression, stress and 
anxiety are found to be associated with greater psychological or psychiatric morbidity in the 
presence of persistent pain following breast cancer surgery (6-8). Similarly, the clustering of 
persistent pain with depression overall occurs in high prevalence ranging from 30% to 60% (9, 
10). The association of depression and persistent pain after breast cancer surgery is, however 
not clear. The knowledge of this relationship could change psychiatric and pain physicians 
practice, e.g. by leading to screening for depression and persistent pain during patient contact, as 
well as, stimulate further research in elucidating common pathways in these two distinct disease 
processes. 
Pain Vulnerability: Pain catastrophizing refers to the negative thought processes patients have 
when they are exposed to pain or painful experiences. There has been increasing evidence 
suggesting that catastrophizing is related to increased pain and reduced activities of daily living 
in patients with chronic pain (11, 12). Identifying patients with pain vulnerability may lead to 
further work in cognitive behaviour or mindfulness therapies that are successful methods of 
treatment for catastrophizing, leading to better adjustment to pain (11, 13, 14). 
 
Anxiety and Stress 
Perceived Stress Scale (PSS) is developed by Cohen et al (15). This instrument assesses the 
individual's perception of stress over the past month and asks questions about thoughts and 
feelings in that time period. The PSS aims to extract information about the degree to which the 
individual values their life as ‘unpredictable, uncontrollable, and overloaded’. Each item is rated 
on a 5-point Likert scale ranging from never (0) to almost always (4). Positive questions are 
scored in reverse order from 4 to 0. Total scores will range from 0 to 40 with the highest scores 
indicating the highest perceived stress. Brief Symptom Inventory 18 (BSI-18) has been used as 
a tool for psychological distress and psychiatric disorders especially in oncology populations. It 
comprises three components: Somatization, depression and anxiety. The respondent’s overall 
level of psychological distress is measured by Global Severity Index (GSI), which is simply the 

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total score of BSI-18. Wells et al. showed that in breast cancer patients, those having implant 
removed had the highest levels of psychological distress (all three components) post-operatively 
as compared to those without implant removal (16). Similar results were also shown in Roberts 
et al., by which those having implant removal had higher BSI scores even during short term (4-9 
months) and long-term (>10 months) follow-up (17). 
 
Central Sensitisation 
Central sensitisation is characterised by allodynia (painful sensation to a normally non painful 
stimulus, such as touch), hyperalgesia (excessive sensitivity to a normally painful stimulus, such 
as pressure), expansion of the pain field and prolonged pain after stimulus has been removed 
(18). The neurobiological mechanism may involve dysregulation in both ascending and 
descending pain pathways as a result of physical trauma and prolonged persistent pain impulses. 
In addition, depression and anxiety are often associated with central sensitisation (19, 20).    
Central sensitisation inventory (CSI) is a screening instrument designed to help clinicians 
identify patients with central sensitisation measuring a full array of central sensitisation 
syndrome related symptoms (18). The CSI has demonstrated good psychometric properties (test 
retest reliability = 0.0817; the Cronbach alpha = 0.879) (18). Importantly, the CSI scores have 
been found to be highly associated with the presence of central sensitisation in persistent pain 
patients referred to an orthopaedic rehabilitation practice specialising in persistent pain and 
psychological disorders (21).  
 
Pain Catastrophizing 
Pain catastrophizing refers to the negative thoughts processes patients have when they are 
exposed to pain or painful experiences. It consists of three components: (1) rumination, (2) 
magnification, and (3) helplessness. Sullivan et al developed the 13 item Pain Catastrophizing 
Scale (PCS), which assesses the three components on a 5 point scale (22). A number of studies 
have replicated these factor structures using confirmatory factor analytic methods in healthy, 
pain-free adults (23, 24), chronic pain patients (24) and across diverse cultural groups and in 
non-English languages (25). Catastrophizing was also found related to increased pain and 
reduced activities of daily living in chronic pain patients (26, 27). Developed by Rosenstiel and 
Keefe, Coping Strategies Questionnaire–Revised (CSQ-R)) uses a pool of items reflecting 
coping strategies frequently reported by patients and deemed to be important by clinicians 
involved in pain management (28). In those with chronic pain, this questionnaire is proven to be 
able to help in determining the patients’ cognitive characteristics and predict treatment 
outcomes (29).  
 
Health assessment 
EQ-5D-3L is a generic preference-based instrument that is widely used to measure health-
related quality of life and can be used to assign preference values to various health states. Several 
studies have utilized EQ-5D-3L to discriminate breast cancer patients with different health 
conditions cross-sectionally (30, 31). Eysenck Personality Questionnaire, revised (EPQ-R) 
indicates the existence of three major traits: neuroticism, extraversion, and psychoticism as well 
as a lie scale to measure the dissimulation. García-Torres et al. demonstrated that breast cancer 
survivors had higher levels of psychoticism compared with a control group, however its link to 
depression remains unclear (32).  

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Pain Genetics after Breast Cancer Surgery 
Catechol-O-methyltransferase (COMT) opioid polymorphisms have been associated with both 
experimental and clinical pain phenotypes. Studies on fibromyalgia syndrome and low back pain 
have found significant associations with COMT polymorphisms Val15Met, rs4680, rs4633 (33-
35), however there is little data after breast cancer surgery. We will investigate specific candidate 
COMT polymorphisms including COMT val158Met, rs4680, rs4633, rs4818 polymorphisms. 
Mutations in sodium SCN9A gene, which encodes the type IX alpha subunit of the voltage-
gated sodium channel, Nav1.7, were found to be linked to pain disorders as primary 
erythermalgia and small fibre neuropathy (36, 37). Duan et al. demonstrated an association 
between SCN9A SNPs (rs4286289, rs4387806, rs16851799) and post-operative pain parameters 
in the gynaecological setting, and further postulated that this polymorphism can be used to 
identify patients at risk of developing severe postoperative pain (38). 
 
The polymorphisms of candidate genes at CACNG2 calcium channels, in particular those 
located near exon 3 and exon 4 of the gene, are associated with persistent pain in breast cancer 
surgery patients (39, 40). Here we propose to look into the role of these SNPs (rs4820242, 
rs2284015, rs2284017, rs2284018, rs1883988) in the persistent pain development after breast 
cancer surgery. 
 
Pain Modelling May Predict Postsurgical Pain 
Previous studies demonstrated good reliability on predicting postoperative pain with the use of 
preoperative indicators (41). We shall construct a model with risk factors including 
psychological vulnerability, pain vulnerability and perioperative factors that influence persistent 
pain development. The interplay of psychological and pain pathways will also be investigated 
through targeted candidate gene polymorphism approach. The relationship between the 
physiological, psychological and genetic factors will guide us in future studies on model 
validation, potential novel risk stratification and identify therapeutic targets.  
 
2. 
HYPOTHESIS AND OBJECTIVES 
 
Our long-term goal is to improve the outcome of women after breast cancer surgery by 
reducing persistent pain and severe acute postsurgical pain. Our objective here is to identify the 
role of perioperative factors, pain vulnerability, psychological vulnerability, quantitative sensory 
testing, and genetics in the development of persistent postsurgical pain. Our central hypothesis 
is that certain risk factors would be associated with the development of persistent pain after 
breast cancer surgery. To investigate this hypothesis, we will evaluate the association of multiple 
risk factors with the development of persistent postsurgical pain. We plan the following specific 
aims: 
 
Primary Aim: To determine if a multivariable model for incidence of persistent postsurgical 
pain after breast cancer surgery may be built by using previously identified and novel measures 
of perioperative risk factors, and subsequently be used as a risk predication tool. 
Primary Hypothesis: Using a subset of perioperative risk factors and measures of pain and 
psychological vulnerability, a model may be created for persistent postsurgical pain that attains 
high discrimination (AUC in ROC analysis >0.70) and calibration. 
 
Secondary Aim: To determine if mechanical temporal summation (MTS) or pressure pain 
threshold are associated with significant acute and persistent postsurgical pain after breast 

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cancer surgery. 
Secondary Hypothesis (1): Evoked MTS would be associated with significant acute 
postsurgical pain and persistent postsurgical pain in women after breast cancer surgery. 
Secondary Hypothesis (2): Lower pressure pain threshold would be associated with 
significant acute postsurgical pain and persistent postsurgical pain in women after breast cancer 
surgery. 
 
Exploratory Aims: To examine the association of personality traits (42), quality of life 
measures and opioid, sodium channel and calcium channel polymorphisms with persistent 
postsurgical pain in women after breast cancer surgery (43, 44).  
 
 
3. 
EXPECTED RISKS AND BENEFITS 
 
Risks: Universal precautions will be used during intravenous cannulation per routine to obtain 
5mls of EDTA blood. During the MTS prick assessment, a test would involve the use of a thin 
plastic tube using repeated sensation of pinprick testing for increased sensitivity of pain to 
pinprick in some individuals. The assessment will be done on the inner side of the patient's 
forearm. 
Analgesic choices will be made upon patient request and routine hospital protocol, monitoring 
and recording will apply. If subjects are screened to have T- score ≥ 63 in global severity index 
(as measured by BSI-18 questionnaire) or persistent pain, they would be advised to seek clinical 
psychiatric or pain assessment at their respective Hospital. The assessment would be done as 
clinical work and not research funded. No new research medications are involved by joining the 
study. The drugs being delivered are the same as what the patient shall receive as standard care. 
 
Benefits: As this will be an observational study, there will be no direct benefits or harms to 
patients who choose to participate in this study. On a population level, the data collected in this 
study may help to improve pain management for women undergoing breast cancer surgery in 
the future. 
 
4. 
STUDY POPULATION 
 
4.1. 
List the number and nature of subjects to be enrolled.  
We propose to recruit 300 patients this prospective cohort study, by which women scheduled 
for mastectomy or lumpectomy surgery for breast cancer in KKH and Duke University 
Hospital will be invited to participate in the study to identify patients who are at high-risk of 
developing persistent post-surgical pain. Subjects will be managed according to standard of care 
at both institutions.  
 
4.2. 
Criteria for Recruitment and Recruitment Process 
 
This study will be advertised on study posters and brochures. These will be placed in the pre-
operative assessment clinics and pre-admission areas. Patients who are undergoing breast cancer 
surgery will receive study information either at pre-operative assessment clinic or upon 
admission for surgery if they have not attended the pre-operative assessment clinic. They will be 
screened for eligibility using the inclusion and exclusion criteria. If eligible for recruitment, the 
patients will be approached by the investigators for recruitment. Recruitment will be performed 
in the pre-operative assessment clinic or on the same day of surgery if they have not attended 

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pre-operative assessment clinic. Research personnel will conduct all discussions about the study 
and answer any questions in a private manner in the consultation rooms. They will be 
counselled regarding the alternatives and given an opportunity to ask questions and clarify 
doubts. Ample time will be given to the potential patients for consent taking. Consent will be 
obtained in writing upon their willingness and agreement to participate in the study.  
 
4.3. 
Inclusion Criteria 
 
The subject will only be recruited into this study if she has met all the below criteria: 
 
a. 
Aged between 21 – 80 year old;  
b. 
Healthy and/or have systemic medical conditions as reviewed by anaesthetist for surgery 
(ASA 1-3); 
c. 
Undergoing breast cancer surgery. 
 
 
4.4. 
Exclusion Criteria 
 
Any subject meeting one and/or above exclusion criteria as listed below will be excluded from 
participating in the study: 
 
a. 
History of intravenous drug or opioid abuse; 
b. 
Current chronic daily treatment with corticosteroids (excluding inhaled steroids); 
c. 
Previous history of chronic pain syndrome; 
d. 
Obstetric patients. 
 
 
5. 
STUDY DESIGN AND PROCEDURES/METHODOLOGY 
 
We propose to recruit 300 patients this prospective cohort study, by which women scheduled 
for mastectomy or lumpectomy surgery for breast cancer in KKH and Duke University 
Hospital will be invited to participate in the study to identify patients who are at high-risk of 
developing persistent post-surgical pain. Subjects will be managed according to standard of care 
at their respective institution.  
 
a. 
Pre-operative assessments 
A pre-operative evaluation will involve: 
(i)     Comprehensive preoperative demographic, surgical, anaesthetic and pain evaluation, need 
for axillary clearance, preoperative/ postoperative chemotherapy/ radiation therapy; 
(ii)     Pain vulnerability and coping assessment (Pain catastrophizing scale (PCS),  Central 
Sensitisation Inventory (CSI), Coping Strategies Questionnaire–Revised (CSQ-R), postsurgical 
pain scores); 
(iii)    Psychological vulnerability assessment (Distress (Brief Symptom Inventory-18 (BSI-18)), 
and stress (perceived stress scale (PSS))); 
(iv)    Experimental pain testing (mechanical temporal summation (MTS), pressure pain 
threshold); 
(v)     Health assessment (quality of life (EQ-5D-3L) and personality (Eysenck Personality 
Questionnaire (EPQ)); 
(vi)    Genetic profiling via blood samples. 
 

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The above activities will be performed in pre-operative assessment clinics and/or pre-admission 
areas. The questionnaires may also be completed post-operatively in the patients ward, before 
their discharge. 
 
Mechanical temporal summation (MTS) 
A pre-test will be performed on the subject’s forearm, by which a 180 gram von Frey filament is 
applied once or twice to familiarize the patient with the pinprick sensation. Patient will then be 
asked to rate the pinprick pain score on a verbal rating scale, 0-100. 
The actual test will firstly involve the one-time application of the filament. Patient will be asked 
to rate the pain score (0-100). Following this, 10 consecutive touches at random locations are 
applied with a 1 second interstimulus interval and within a 1 cm diameter circle. The patient will 
then be asked to rate the 10th pain score (0-100). 
 
Pressure pain threshold assessment  
A pre-test will be performed on the subject’s right centre of 
the trapezius muscle, by which pressure is applied 90 degree 
straight down force using an algometer. The speed of 
pressure will be about 1kgf per second (to be estimated by 
investigator prior to pre-test using pressure on own’s hand 
to estimate speed). 
The above procedure is then repeated 2-3 times at the same 
site which is indicated on the pressure mark with each time 
having the readings recorded.  When patient shows no 
response ≥ 6kgf, the threshold will be recorded as 6kgf. 
The patient upon feeling pain will say stop or raise the hand 
to terminate the test. The number of obtaining readings is determined by the below conditions: 
i) 2 values are recorded within 0.2kgf of one another. The mean value is obtained by averaging 2 
readings;  or ii) (If applicable) If the 2 values from i) have a difference of >0.2kgf, a third test 
will be performed. The mean value is obtained by averaging 3 readings. The final mean value 
will then be recorded as the threshold estimate.  
The above procedures will be repeated again on the patient’s left center of the trapezius muscle. 
 
Questionnaire administration 
Questionnaires will be administered either via paper format or online survey, whichever the 
patient prefers and feels comfortable with. Chinese-translated questionnaires are made available 
provided patients prefer answering the questionnaires using Chinese. The designated study team 
members shall ensure the completeness of the answers upon questionnaire submission.  
 
Blood taking  
Five mls of blood will be obtained during routine intravenous cannulation or routine blood 
taking before the start of the surgery as per routine, which allow study team to collect the blood 
in EDTA tube to reduce additional injections. If this is not possible, a separate injection will be 
done with patient's consent. The blood taking will be performed by accredited nurses and 
doctors, and no protocol-specific training is required to perform the intravenous cannulation as 
this is part of the routine practice.  
DNA will be extracted from venous blood using the Puregene method. Known functional 
polymorphisms in the candidate genes, SCN9A, COMT and CACNG2 with evidence of 
associations with depression, pain, stress and anxiety would be determined by the Taqman allelic 
discrimination assay method using the ABI Step-One Plus Real-time PCR System (Applied 

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Biosystems, Foster City, California, USA). Alleles will be called using the software. Genetic data 
will be analysed for association with post-operative pain and psychological vulnerability. Blood 
obtained may also be analysed for metabolomics and proteomics for biomarkers. The results 
obtained from these tests will not be communicated to the subjects as these information would 
not affect the clinical decisions about the individual's care and have no effect on the 
participants.  
 
b. 
Post-operative assessments 
Perioperative anaesthetic management will be recorded and outcomes including analgesic 
consumption, pain scores at surgery site, arm and armpit (at rest/ with movement) as well as 
adverse events (if any) will be collected in the post anaesthesia recovery unit and at 1-, 2- and 3-
days after surgery. Study team members will also follow up with patients to ensure completion 
of questionnaires administered in section a. 
 
Follow-up evaluation at 4 and 6 months, respectively will involve: 
(i)      Pain assessment; 
(ii)     Health assessment via EQ-5D-3L questionnaire. 
 
The above assessment may be done via phone survey or online survey, whichever the patient 
prefers and feels comfortable with.  
 
Patients will be involved in the study before their admission to the hospital for surgery, which 
may take up to 4 weeks. Blood sample taking and questionnaires will be conducted during their 
hospitalization stay, i.e. from the time just before surgery until the patient is discharged from the 
post-operative observation area. This will take about 3-4 days. Phone or online surveys will be 
conducted at 4 and 6 months, respectively, after surgery. The total amount of time by which 
participants are involved in the study will therefore take about 7 months. 
 
Discontinuation/ Withdrawal 
 
Patients are free to withdraw/discontinue the study at any time (including timing after their 
surgery), should they decide not to participate. Patient will be withdrawn /discontinued from the 
study if : 
 Severe adverse effects and unforeseen reactions that affect the wellbeing of the subjects 
(with reporting to relevant regulatory authority and CIRB); 
 Study closure due to CIRB review. 
 
If the patient withdraws from the study, she will be given routine standard care based on the 
current hospital procedures. However, the data that have been collected until the time of her 
withdrawal will be kept and analysed. The reason is to enable a complete and comprehensive 
evaluation of the study.  
Subject who miss any of the follow up, visit or assessment will be excluded from data analysis for 
that assessment. Subjects who have their assessment outside of window period will be regarded 
as protocol deviation. 
 

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6. 
SAFETY MEASUREMENTS 
6.1. 
Definitions 
An adverse event (AE) is any untoward medical occurrence in a patient or clinical investigation 
subject administered a pharmaceutical product and which does not necessarily have a causal 
relationship with this treatment. 
 
In this study, the following conditions will be documented as adverse events (AE): 
 Unplanned intubation after surgery 
 Pulmonary embolism 
 Other unexpected adverse event which are related events 
 
A serious adverse event (SAE) or reaction is any untoward medical occurrence that at any dose: 
 results in death 
 is life-threatening 
 requires inpatient hospitalisation or prolongation of existing hospitalisation 
 results in persistent or significant disability/incapacity or 
 is a congenital anomaly/birth defect 
 is a medical event that may jeopardize the patient and may require medical or surgical 
intervention to prevent one of the outcomes listed above. 
 
A serious adverse event (SAE) or reaction is any untoward medical occurrence that at any dose: 
 results in or contributes to death 
 is life-threatening 
 requires inpatient hospitalisation or prolongation of existing hospitalisation 
 results in or contributes to persistent or significant disability/incapacity or 
 results in or contributes to a congenital anomaly/birth defect 
 results in such other events as may be prescribed  
 
6.2. 
Collecting, Recording and Reporting of Adverse Events and Serious Adverse 
Events to CIRB 
 
Reporting of adverse events involves the PI submitting to the approving CIRB the completed 
SAE Reporting Form within the stipulated timeframe. PI is responsible for informing the 
institution representative (local SAE resulting in death), sponsor or regulatory bodies as 
required and appropriate. 
 
Reporting timeline to CIRB:  
 
 SAE that result in death, regardless of causality, should be reported immediately - within 
24 hours of the PI becoming aware of the event.  
 Local life-threatening (unexpected/ expected) SAE should be reported no later than 7 
calendar days after the Investigator is aware of the event, followed by a complete report 
within 8 additional calendar days. 
 Local unexpected SAE that are related events, but not life-threatening, should be 
reported no later than 15 calendar days after the investigator is aware of the event. 
 An increase in the rate of occurrence of local expected SAE, which is judged to be 

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clinically important, should be reported within 15 calendar days after the PI is aware of 
the event.  
 Local expected SAE should be reported annually (together with Study Status Report for 
annual review). 
 Local unexpected and unlikely related SAE that are not life-threatening should also be 
reported annually (together with Study Status Report for annual review). 
 Local unexpected AE that are related events should be reported at least annually 
(together with Study Status Report for annual review). 
 Non-local 
unexpected 
SAE 
that 
are 
fatal 
or 
life 
threatening 
and 
definitely/probably/possibly related should be reported not later than 30 calendar days 
after the PI is aware of the event. 
 
6.3. 
Safety Monitoring Plan 
 
Patients involved in the study will be monitored for adverse events in the same manner that 
safety is monitored for standard-of care. The patient’s vital signs, i.e. pulse rate, heart rate, blood 
pressure, respiratory rate will be recorded at regular standard routine intervals during and after 
the administration of the analgesia medications. The vital signs monitoring will continue 
throughout the surgery according to routine practice. The incidence and severity of side effects 
like nausea and/or vomiting and pain will be closely monitored after the procedure. Any serious 
adverse events will be immediately reported to the principal investigator. The patients will be 
treated for side effects according to hospital protocols. 
 
Safety Recording: 
All adverse events and serious adverse events will be recorded on adverse event form and 
serious adverse event forms will be recorded on the subject case report form. All unexpected 
adverse events and serious adverse events (whether expected or unexpected) will be reported to 
the principal investigator reviewed at each team meeting. 
 
 
6.4. 
Complaint Handling  
 
During the informed consent process, subjects will be advised to discuss with the investigator if 
they have any concerns during the study. The contact information of the principal investigator 
is provided in the consent form. Complaints arising from the conduct of the study will be 
discussed at the next available study team meeting.  
 
Subjects will be provided with the contact details of the Principal Investigator and the CIRB. 
The Principal Investigator will speak directly to the complainant and resolve it as soon as 
possible. Any serious or potentially litigious complaints will be reported to the respective 
regulatory authorities and Institutional Review Board.  
 
If the subject is unwilling to continue with the study, she will be assured that she can withdraw 
without any repercussions. If a subject wants her data excluded from the study, then her records 
will be removed from the study documents and database. 
 
 

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7. 
DATA ANALYSIS 
7.1. 
Data Quality Assurance 
 
To ensure data quality, entered data will be systematically checked and validated against the 
rules, including range and logic checks, which are built into the REDCap database system. Any 
discrepancies will be channelled to the relevant parties for resolution. All discrepancies will be 
resolved prior to data analysis. Quality control audits of all key safety and efficacy data in the 
database will be made before database lock. 
 
Several procedures will be implemented to ensure accurate, complete, and reliable data for the 
study: 
 
• 
The roles and responsibilities for the study team will be segregated. The study will be 
monitored by designated monitors. The study monitors will follow the study monitoring plan 
and verify that: 
 
- 
the rights and well-being of human subjects are protected; 
- 
the reported trial data are accurate, complete, and verifiable from source documents;  
- 
the conduct of the trial is in compliance with the currently approved protocol 
/amendment(s), with GCP, and with the applicable regulatory requirement(s). 
 
• 
A start up meeting will be held with the whole study team; study personnel who will 
handle data collection and data entry will be appropriately trained during the meeting before the 
study start. 
 
• 
The investigator will keep records of all original source data, in anticipation or audits by 
respective agencies/institutes. This might include laboratory tests, medical records, and clinical 
notes. If requested, the investigator will provide them with direct access to the original source 
documents. 
 
7.2. 
Data Entry and Storage 
 
Data will be collected from the source documents including the hospital medical records as well 
as the study specific questionnaires. A source documentation checklist will be used at the site to 
identify the source data for all data points collected. All source documents will be handled with 
strict confidentiality. It will be stored in locked cupboards which are only accessible by 
designated staff only. All source documents can only be reviewed by external personnel after 
confirmation of the identity check. 
 
An electronic database REDCap will be used for data entry into case report form (CRF). Data 
reported on the eCRF that are derived from source documents should be consistent with the 
source documents. If there are discrepancies, these should be explained. Password protected 
accounts will be created for relevant study personnel and the degree of database access granted 
to the each relevant study personnel account will correspond to their trial responsibilities. The 
data will be kept under lock using the computer security of respective institution and will be 
destroyed upon keeping for up to 6-years after completion of the study. 
 
 

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8. 
SAMPLE SIZE AND STATISTICAL METHODS 
 
8.1. 
Determination of Sample Size  
 
Based on the Haneley and McNeil variance formulas (45), a number of 152 patients, with a 50% 
incidence of persistent pain, will produce a 95% lower confidence bound for area under the 
ROC curve (AUC) >0.70 if the observed AUC is 0.77. We anticipate a 30% drop-out rate and 
will therefore enrol 218 patients to ensure adequate sample to assess our primary hypothesis. If 
the drop-out rate was lowered to 20% we would be able to produce a 95% lower confidence 
bound for AUC >0.70 if the observed AUC0.76. Since this is a collaborative project between 
KKH and Duke, both KKH and Duke will therefore recruit 109 patients, respectively in their 
research sites. To further take into account uncertain circumstances, a number of 150 patients 
will be recruited in KKH and Duke University Hospital site, respectively. 
 
8.2. 
Statistical and Analytical Plans 
We will study risk factor distributions to determine the appropriate summary statistics [(mean 
(SD), median (Q1, Q3), or N (%)] and modelling strategies (transformations, functional form, 
collinearity, interaction potentials). As this study will combine data across two sites we will 
investigate differences between patients and outcomes between sites to determine how site 
should be accounted for in the analysis. 
 
We will use generalized estimating equations (GEE) to generate univariate association statistics 
with a random effect for site (46). A combination of variable selection criteria including 
statistical significance, improvement of QIC (GEE equivalent of AIC), Mallow’s Cp, Brier 
score, ROC AUC, and integrated discrimination index will be used to build our model (47-52). 
ROC analysis will be performed by outputting the estimated probabilities of persistent pain 
from GEE analysis, followed by simple logistic regression of persistent pain on those predicted 
values. After a final model is selected its performance will be internally validated via bootstrap 
resampling, and externally validated with prior data from Duke. By performing these validations 
we can evaluate the model performance for future cohorts and avoid a cohort specific 
formulation or over-optimization. 
 
Of particular interest in this study is the effects of MTS, pressure pain threshold, minor allele 
frequencies (MAF) and their associations with the incidence of persistent pain. We will 
investigate the association of these factors via univariate analysis and by forcing their inclusion 
in the final multivariable model established during analysis for the primary aim. Hardy-weinberg 
equilibrium test will be conducted to assess whether MAF in our cohort is representative of the 
population. GEEs will be used to account for potential cluster effects, and to explore 
interactions of these factors with patient characteristics to identify possible subgroup effect. All 
analyses will be conducted in SAS or R. Statistical significance will be set at 0.05 level, and all 
model parameters will be presented with point estimate and 95% confidence intervals. 
 
We will study risk factor distributions to determine the appropriate summary statistics [(mean 
(SD), median (Q1, Q3), or N (%)] and modelling strategies (transformations, functional form, 
collinearity, interaction potentials). As this study will combine data across two sites we will 
investigate differences between patients and outcomes between sites to determine how site 
should be accounted for in the analysis. 
 

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9. 
DIRECT ACCESS TO SOURCE DATA/DOCUMENTS 
 
The investigator will keep records of all original source data, in anticipation of study-related 
monitoring, review and/or audits by respective agencies/institutes. This might include 
laboratory tests, medical records, clinical notes, and questionnaires. If requested, the investigator 
will provide them with direct access to the original source documents. 
 
The subject has the right to request access to her personal data and the right to request 
rectification of any data that is not correct and/or complete. Reasonable steps should be taken 
to respond to such request, taking into consideration the nature of the request, the conditions 
of the study, and the applicable laws and regulations.  
 
If subjects are screened to have high depression/anxiety or persistent pain, they would be 
advised to seek clinical psychiatric or pain assessment at their respective hospital. In this case 
the subject’s data may be assessed by respective personnel upon request.   
 
 
10. 
QUALITY CONTROL AND QUALITY ASSURANCE 
 
During and/ or after completion of the study, quality assurance officers named by the study 
Principal Investigator or regulatory authorities may wish to perform on-site audits.  The 
Investigator and site personnel will be expected to cooperate with any audit and to provide 
assistance and documentation (including source data) as requested.  The Investigator and site 
personnel will immediately inform the study Principal Investigator of any audit to be performed 
by a regulatory authority. 
 
 
11. 
ETHICAL CONSIDERATIONS 
 
This study will be conducted in accordance with the ethical principles that have their origin in 
the Declaration of Helsinki and that are consistent with the Good Clinical Practice and the 
applicable regulatory requirements. 
 
This final study protocol, including the final version of the Patient Information and Informed 
Consent Form, must be approved in writing by the Centralised Institutional Review Board 
(CIRB), prior to enrolment of any patient into the study. 
 
The principle investigator is responsible for informing the CIRB of any amendments to the 
protocol or other study-related documents, as per local requirement. 
 
 
11.1. Informed Consent 
 
Informed Consent will be taken for all study subjects. The informed consent process will be 
conducted by a trained study team member as shown in the delegation log. The informed 
consent process will be conducted in compliance with ICH-GCP.  
 

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11.2. Confidentiality of Data and Patient Records 
 
Names and other identification numbers of all subjects will be de-identified. The subjects are 
only identified by study numbers, by which these numbers would be communicated through in 
electronic softcopy format. The data will be kept locked by the principal investigator and by the 
use of computer security of respective instituition. The data will be accessible only to the 
investigators and for analysis purposes only. 
 
12. 
PUBLICATIONS 
 
The publication policy would follow the guidelines that are stated in both KKH and Duke 
University as well as Singhealth Office of Research for authorship, acknowledgement and 
review procedures. 
 
13. 
RETENTION OF STUDY DOCUMENTS 
 
Data entry will be in softcopy format and will be kept under lock using the computer security of 
respective institution. The data will be destroyed after keeping for 6 years upon completion of 
the study. 
 
 
14. 
FUNDING and INSURANCE 
 
This study is funded by Duke-NUS/SingHealth Collaborative Funding, with an amount of 
$100,000 respectively for each site, approved in year 2017 (Ref no. Duke/Duke-
NUS/RECA(Pilot)/2017/0031).  
 
The Hospital does not make any provisions to compensate study participants for research 
related injury. However, compensation may be considered on a case-by-case basis for 
unexpected injuries due to non-negligent causes, and shall be covered by respective institution. 

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List of Attachments 
 
Appendix 1 
Study Schedule 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

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Appendix 2 
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