Importance: Randomized trials have established the long-term safety and efficacy of hypofractionated whole-breast radiotherapy, but little is known about the acute toxic effects experienced by patients treated with hypofractionation as compared with conventional fractionation, particularly in real-world settings and from the patient's own perspective.
Objective: To evaluate prospectively collected data on acute toxic effects and patient-reported outcomes in a cohort treated with varying radiation fractionation schemes in practices collaborating in the Michigan Radiation Oncology Quality Consortium (MROQC).
Design, setting, and participants: We compared toxic effects in patients receiving hypofractionation (HF) vs conventional fractionation (CF) during treatment (through 7 days after treatment) and in follow-up (posttreatment days 8-210), after adjustment for sociodemographic, clinical, and treatment characteristics. The MROQC includes academic and community radiation oncology practices across Michigan. All 2604 patients who received adjuvant whole-breast radiotherapy after lumpectomy for unilateral breast cancer at MROQC participating sites from October 2011 through June 2014 were registered; we analyzed 2309 for whom there was a comprehensive physician toxicity evaluation within 1 week of completion of radiotherapy and at least 1 weekly toxicity evaluation during treatment.
Exposures: Hypofractionation vs CF.
Main outcomes and measures: Physicians reported dermatitis, pain, fatigue, and other common toxic effects associated with breast radiotherapy at baseline, weekly during radiotherapy, and in follow-up. Patients who consented also rated their own experiences, including breast pain, fatigue, and being bothered by symptoms.
Results: Of the 2309 evaluable patients, 578 received HF. During treatment, after adjustment for sociodemographic, clinical, and treatment factors, patients receiving CF had significantly higher maximum physician-assessed skin reaction (moist desquamation, 28.5% vs 6.6%, P < .001; grade ≥2 dermatitis, 62.6% vs 27.4%, P < .001), self-reported pain (moderate/severe pain, 41.1% vs 24.2%, P = .003), burning/stinging bother (often/always, 38.7% vs 15.7%, P = .002), hurting bother (33.5% vs 16.0%, P = .001), swelling bother (29.6% vs 15.7%, P = .03), and fatigue (29.7% vs 18.9%, P = .02) but slightly greater absence of skin induration in follow-up (84.5% vs 81.2%, P = .02). No significant differences were observed in any other measured outcomes during follow-up extending through 6 months.
Conclusions and relevance: Hypofractionation not only improves convenience but also may reduce acute pain, fatigue, and the extent to which patients are bothered by dermatitis in patients with breast cancer undergoing whole-breast radiotherapy.