The Effectiveness of Cancer Pain Management Including Early Pain Intervention, Early Multi Modality Treatment and Closed Follow up in Siriraj Outpatient Pain Clinic
Conditions: Pain, Chronic, Cancer
Sponsor: Mahidol University

Study protocol with Statistical analysis plan 
 
Title: The Effectiveness of Cancer Pain Management in 
Tertiary Hospital Outpatient in Thailand: Prospective 
observational study. 
 
NCT: 03474406 
 
Date of document: October 18th, 2020 
 
Faculty location: 
Pain Clinic, Department of Anesthesiology, Faculty 
of Medicine, Siriraj Hospital Mahidol University 
2 Wang Lang Rd, Bangkok Noi, Bangkok, Thailand 
10700 

Study Protocol 
With approval from the Siriraj Institutional Review Board (Number Si 622/2017) and 
registered ClinicalTrials.gov (NCT03474406), we conducted a prospective observational study of 
patients 18 years and older who received a new consult for cancer pain at the Siriraj Pain Clinic 
from January to December 2018. Written informed consent was obtained from all patients. We 
excluded patients who had difficulties with listening, reading, and writing Thai and those who 
were unable to interpret the evaluation form/questionnaires.  
All patients enrolled in the study received standard care by pain specialists in the clinic. 
The WHO analgesic guidelines, selective consideration of pain interventions, and nurse-directed 
analgesic rescue program were implemented. Additionally, patients received a phone call as a 
reminder to attend follow-up visits. Patients were followed every 2-4 weeks based on physician 
judgment and pain severity.  
 Data collection and outcome measures 
The primary outcome of this study was the percentage of patients defined as “pain 
responders” by either 30% reduction in  pain intensity rating or pain intensity less than 4 at the 
third follow-up visit (FU3). Secondary outcomes included pain interference, other symptom 
scores, side effects, and analgesic prescribing and consumption.  
Data were collected at baseline and at three follow-up times (FU1, FU2, FU3). Patients’ 
baseline demographic data (age, gender, marital status, and education) and clinical characteristics 
(Cancer status, stage, and sites of involvement) were recorded. Pain severity, performance status, 
pain interference, other symptoms, side effects, pharmacological treatments and dosage, and 
patient satisfaction were recorded at every visit. We retrospectively reviewed palliative care 
medical records for additional data related to pain intensity, performance status, opioid 

consumption, date of first palliative care visit, and dates of death, if applicable. Data were collected 
by research assistants, nurses, and physicians and entered into Case Report Forms.  
Statistical analysis Plan 
Analyses were performed using SPSS statistical package 21.0 (SPSS, Inc., Chicago, IL). 
Categorical data are reported as numbers and percentages, and continuous data are reported as 
median (IQR). Repeated measures designs used Friedman tests for continuous data and 
Cochran’s Q for dichotomous data, with post-hoc comparisons at each time point using the 
Wilcoxon matched-pairs signed rank test for continuous variables, McNemar tests for 
dichotomous variables, and the Marginal Homogeneity test for a categorical variable with 3 or 
more values. Comparison of continuous variables between two independent populations was 
assessed using the Mann-Whitney test. Comparison between more than two independent 
populations was assessed using the Kruskal-Wallis test, with post-hoc Dunn’s Bonferroni tests 
between groups. Variables with p-value<0.1 in the bivariable analyses were considered for entry 
in subsequent multivariable analyses. A significance level of 0.02 was chosen to account for 
repeated comparisons across 3 time points.