Conventional versus hypofractionated postmastectomy radiotherapy: a report on long-term outcomes and late toxicity

Abstract

Objective We evaluated the long-term outcomes and late toxicity of conventional fractionated (CF) and hypofractionated (HF) postmastectomy radiotherapy (PMRT) in terms of locoregional recurrence-free survival (LRRFS), disease-free survival (DFS), overall survival (OS), and late toxicity. Methods A cohort of 1640 of breast cancer patients receiving PMRT between January 2004 and December 2014 were enrolled. Nine hundred eighty patients were treated with HF-PMRT: 2.65 Gy/fraction to a total of 42.4–53 Gy and 660 patients were treated with CF-PMRT: 2 Gy/fraction to a total of 50–60 Gy. Results The median follow-up time was 71.8 months (range 41.5–115.9 months). No significant difference was found in the rates of 5-year LRRFS, DFS, and OS of HF-PMRT vs CF-PMRT; 96% vs. 94% (p = 0.373), 70% vs. 72% (p = 0.849), and 73% vs. 74% (p = 0.463), respectively. We identified a cohort of 937 eligible breast cancer patients who could receive late toxicities assessment. With a median follow-up time of this patient cohort of 106.3 months (range 76–134 months), there was a significant higher incidence of grade 2 or more late skin (4% vs 1%) and subcutaneous (7% vs 2%) toxicity in patients treated with HF-PMRT vs CF-PMRT. Patients who received additional radiation boost were significantly higher in the HF-PMRT group. Grade 2 or more late RTOG/EORTC lung toxicity was significant lesser in HF-PMRT vs CF-PMRT (9% vs 16%). Grade 1 brachial plexopathy was also significant lesser in HF-PMRT vs CF-PMRT (2% vs 8%). Heart toxicity and lymphedema were similar in both groups. Conclusions HF-PMRT is feasible to deliver with comparable long-term efficacy to CF-PMRT. HF-PMRT had higher grade 2 or more skin and subcutaneous toxicity but less lung and brachial plexus toxicity.

Breast Radiation Therapy Under COVID-19 Pandemic Resource Constraints—Approaches to Defer or Shorten Treatment From a Comprehensive Cancer Center in the United States

“…39,40 As a result, an increasing number of patients have become eligible to receive comprehensive regional nodal irradiation after breast conservation or PMRT. Unfortunately, hypofractionated nodal irradiation has yet to see widespread adoption in the United States, although a nascent literature does suggest it is safe to employ 40 Gy in 15 daily fractions targeting the breast/chest wall and regional nodes (presuming the supraclavicular hotspot is below 105%; otherwise, 39 Gy in 15 fractions is preferred), 33,[41][42][43] with ongoing studies using this regimen in a randomized fashion to suggest true clinical equipoise (RT-CHARM: NCT03414970; FABREC: NCT03422103). The UK FAST FORWARD trial includes a 5-fraction lymphatic RT cohort, but this is not yet considered safe outside of a trial or in the setting of palliation.…”

Recent advances in radiotherapy of breast cancer

“…Multiple randomized trials compared normofractionated (25-28 Fractions in 1.8-2.0 Gy single doses) to hypofractionated RT schedules (single doses > 2.0 Gy in 15-16 fractions) [28,29]. Overall, fraction sizes greater than 2.0 Gy did not affect local recurrence, was associated with decreased acute toxicity and did not affect breast cosmesis, late toxicity or quality-of-life [30,31]. These shorter regimens have been adopted mainly for lower risk patients after breast conserving surgery (BCS) but not thoroughly in PMRT with treatment of the RNI due to concerns regarding risk of lymphedema and brachial plexopathy.…”

Cost-effectiveness of postmastectomy hypofractionated radiation therapy vs conventional fractionated radiation therapy for high-risk breast cancer

“…There is growing interest in continuing study of hypofractionation after postmastectomy [10]. Emerging evidence has suggested that postmastectomy HFRT may be as effective as CFRT for patients at high risk of locoregional recurrence [11][12][13][14][15][16].…”