Quantification of patient-reported outcome measures of radiation-induced skin reactions for use in clinical trial design

• Published in: Supportive care in cancer Vol. 25; no. 1; pp. 67 - 74
• Main Authors: Russell, N. S., van Werkhoven, E., Schagen, S. B.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 2017; Springer; Springer Nature B.V
• Subjects: Adult; Aged; Aged, 80 and over; Breast Neoplasms - complications; Breast Neoplasms - radiotherapy; Cancer patients; Clinical outcomes; Clinical trials; Comparative analysis; Female; Humans; Medical research; Medicine; Medicine & Public Health; Middle Aged; Nursing; Nursing Research; Oncology; Original Article; Pain Medicine; Patient outcomes; Patient Reported Outcome Measures; Prognosis; Radiation; Radiation (Physics); Radiotherapy; Rehabilitation Medicine; Skin; Skin Diseases - chemically induced; Strategic planning (Business); Surveys and Questionnaires; Patient-reported outcome measures (PROM); Radiation toxicity; Radiation dermatitis
• ISSN: 0941-4355; 1433-7339
• DOI: 10.1007/s00520-016-3376-y

Purpose
Skin toxicity is a common effect from radiotherapy, although difficult to predict on an individual basis, and there is little evidence-based management. This study aimed to quantify inter-patient variation in patient-reported outcome measures for radiation-induced skin reactions (RISR) to enable the determination of the number of patients required for adequate power in a comparative trial of RISR management strategies.
Methods
The study included 154 patients scheduled to receive breast cancer radiotherapy. Patients filled in a weekly questionnaire during and up to 4 weeks following the end of radiotherapy scoring five aspects of their experience of RISR: skin redness, and bother from redness like itching, burning sensation and tenderness/pain.
Results
Assessment of patients’ reported experience of their RISR was shown to be feasible, with 91 % of patients returning at least two questionnaires. The mean score increase between weeks 1 and 4 was 25 points (
p
value <0.0001, 95 % CI 21–29), and the estimated standard deviation at 4 weeks was 18 (95 % CI 16–21).
Conclusions
Patients’ assessment of their reaction was not predicted on the basis of treatment and patient-related characteristics. Based on the observed variance in scores at 4 weeks, we could calculate the sample size required for a comparative study of two RISR management policies would be 200 patients to have statistical power to detect a clinically significant difference in patient-rated scores of their skin reactions. A trial employing this tool would help provide an evidence base to guide policy in advising patients how to manage their RISR.