The Effect of White Light on Fatigue Levels in Patients With Gynecological Cancer: A Double Blind Randomized Trial
Phase: NA
Conditions: Cancer-related Fatigue, Light; Therapy, Complications
Sponsor: Eskisehir Osmangazi University

The Effect of White Light on Fatigue Levels in Patients With Gynecological Cancer: A 
Double Blind Randomized Trial 
02.08.2021 
STUDY PROTOCOL 
Study design and participants 
 
This was a triple-blind randomized study. The study included two parallel groups 
consisted of 72 patients who met the inclusion criteria and were receiving outpatient 
chemotherapy for gynecological cancer. The sample size in this study was 72 subjects: 36 in 
the intervention group and 36 in the control group. This study was based on an effect size of 
0.25, a first type error of 5%, and 80% power, relying on the results of a previous study that 
evaluated the effect of bright white light on the fatigue levels of patients with cancer.[16] 
Patients aged over 18 years, had a normal state of consciousness, had no communication 
disorders, did not work in the night shift, had a general fatigue level score of ≥1 according to 
the Brief Fatigue Inventory(1,2), and could perceive light were included in the study. Patients 
who had natural/artificial lenses, used medication that causes photosensitivity (tetracycline, 
doxycycline, nalidixic acid, voriconazole, amiodarone, hydrochlorothiazide, naproxen, 
piroxicam, chlorpromazine), and had a change in their treatment plan in the last 6 weeks were 
not included in the study. 
 
A total of 132 women were admitted to the clinic at the time of the study. All of them 
were evaluated as per the conditions of inclusion criteria. Twenty-five women who did not meet 
the inclusion criteria and another 12 who refused to participate in the study were not included 
in the study. Therefore, a total of 89 women, 47 in the intervention group and 42 in the control 
group, were included in the study through randomization. However, six women from the 
intervention group and three from the control group were excluded from the study because of 
various reasons such as rejecting white light administration, familial reasons, and reaching 
saturation in stratification according to the fatigue level factor. Thus, the study was conducted 

with a total of 72 women with 36 in each group (Figure). Patients and at least one of their 
relatives were informed about the research process and the use of white light in the patient 
room, along with visual materials. It was ensured that the informed consent form was ready by 
the patient and, if necessary, a relative. After obtaining written consent and signatures from the 
patients, the study was initiated.  
Randomization and blinding 
The study participants were stratified into intervention and control groups using 
stratified and block randomization methods, respectively. Firstly, patients who met the 
inclusion criteria and accepted to participate in the study were stratified according to the 
severity of fatigue (1-3 points, mild; 4-6 points, moderate; 7-10 points, severe fatigue). For 
block randomization, at least 10 blocks were selected by random drawing among 20 blocks 
(permutations block 6 and block of size 3 with 1:1) produced by the researchers on SAS 9.4 
(SAS Institute Inc., Cary, NC) software package (3-5). Random assignment was continued until 
there were an equal number of patients (12 patients in each 3 strata) according to their fatigue 
levels in each group, and the groups consisted of 36 patients (Figure).  
 
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Figure. Diagram of participant flow through study 
 
 
 
 
 
Assessed for 
eligibity (n:132) 
Enrolled (n:95) 
Excluded (n:37) 
-Not meeting included kriteria (n:25) 
-Declined to participate (n:12) 
Randomized 
(n:89) 
Allocated to intervention 
group (n:47) 
Allocated to  control 
group (n:42) 
Pre- randomization 
voluntary withdrawals (n:6) 
-Caregivers refuse (n:4) 
-Unknown (n:2) 
Drop out  (n:11) 
-Family issues (n:2) 
-Unwillingness (n:4) 
- Not meeting the stratified 
randomization criteria (n:5) 
Drop out  (n:6) 
-Family issues (n:3) 
- Not meeting the stratified 
randomization criteria (n:3) 
Analyzed (n:36) 
- mild fatigue (n:12) 
-middle fatigue (n:12) 
-severe fatigue (n:12) 
Analyzed (n:36) 
- mild fatigue (n:12) 
-middle fatigue (n:12) 
-severe fatigue (n:12) 
Intervention on 2.-8. days 
with 10.000 lux White light 
Routine care (n:36) 
Allocation  
Follow-up 
Analyses 

A researcher among the authors who was not involved in patient care and 
implementation of interventions evaluated patients for eligibility, enumerated them, collected 
baseline data, and assigned them to research groups. Moreover, this researcher assigned the 
research groups at the beginning of the research, the intervention group “A,” whereas the 
control group was coded with the letters “B.” Two research assistants (RA) were recruited and 
trained for this study. Research assistants were two nurses with a bachelor’s degree, who were 
independent of each other and the researchers. The groups to which the patients belonged were 
reported to the nurses using the appropriate letter code. The first nurse (RA1) who made the 
interventions to the intervention group. The post-intervention evaluation of the patients in the 
application and control groups and the entry of the obtained data into the statistics program 
were made by the other nurse (RA2) who was not informed about the application. Thus, the 
nurse (RA2) who conducted the evaluations, were blinded. During data entry, coding of the 
groups was continued. A biostatistician, who was unaware of the purpose of the research, 
interventions, and groups, performed statistical analysis on the research data. Further, the 
coding of the groups was terminated by the authors at the end of the analysis. In this manner, 
double blinding was achieved in the study.  
Outcomes and instruments 
Observation, interview, and measurement methods were used to collect the data. “Brief 
Fatigue Inventory (BFI)” and “Descriptive Information Form” were used to evaluate the fatigue 
level of the patients on the first, ninth, and twenty-first days. The patients’ demographic and 
medical characteristics were obtained from their medical records. 
The Descriptive Information Form: This form was used to collect information on the 
sociodemographic characteristics, diseases, and treatments of the patients. 
The Brief Fatigue Inventory (BFI): This inventory was developed by Mendoza et al. (1999) to 
evaluate the general fatigue level and its effect on activities of daily living in patients with 

cancer. The study evaluating its validity and reliability for the Turkish context was carried out 
by Çınar et al.(2000) Cronbach’s alpha internal consistency coefficient of the inventory was 
found as 0.98. The BFI consists of nine items in total, with three evaluating general fatigue and 
six evaluating the effect of fatigue on daily life. Individuals rate all items on a scale of “0” (no 
fatigue) to “10” (the most severe fatigue you can experience), taking into account their status 
in the last 24 hours. The “general fatigue” level is calculated by taking the average of the first 
three items of the inventory. The average of the last six items yields a score for the effect of 
fatigue on the activities of daily living. According to the scores obtained from the BFI, the 
severity of fatigue of the individual was “0, no fatigue; 1–3, mild; 4–6, moderate; and 7–10, 
severe fatigue”.  
Interventions 
 Descriptive Information Form and the BFI were administered to the patients in both 
groups on the first day of the application phase, and their baseline assessment was made, which 
was followed by interventions for energy conservation (organizing the patient’s sleep–rest 
hours, supporting activities of daily living, organizing the living environment, etc.) and energy 
enhancement (adequate and balanced nutrition). The patients were informed about the study 
procedure. Between the second and the eighth days of the application phase, the patients in the 
intervention group were administered a standard white light at 10,000 Lux intensity by an 
independent nurse (RA1) in their home environment using a Litebook Elite light source (The 
Litebook Company Ltd., Medicine Hat, AB). The distance between the light source and the 
patient’s face was set at 50 cm, and the intensity of the light for each patient was checked using 
a Lux Meter. The intervention was applied between 07:00 and 10:00 in the morning for 30 
minutes without interruption, and it was continued for seven successive days. The light 
application procedure was followed based on the previous studies on oncology patients. [16,25] 
The patient was asked to engage in other activities during the light administration, such as 

watching television, reading books, and not to look directly at the light. The second and third 
evaluations of the fatigue status of both groups of patients were completed on the 9th and 21st 
days by an independent other nurse (RA2). 
Data analysis 
The statistical analysis was performed on IBM SPSS v.24 (SPSS, Chicago, IL) software 
package. To compare the socio-demographic characteristics of groups, independent groups t-
test and chi-square analysis were used. Paired samples t-test was used to determine differences 
between the study groups, and analysis of variance (repeated measurements ANOVA) was 
employed in repeated measurements. To ensure the balance between the groups and the 
reliability of the intervention results, the intention-to-treat method was not used in the analyses. 
Statistical significance level was accepted as p <0 .05. 
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