Hypofractionated whole-breast irradiation (HF-WBI) has not been widely adopted among women with early-stage invasive breast cancer, in part because of safety concerns when used with a tumor bed boost or in patients who have received chemotherapy or have large breast size. However, a new study shows those concerns may not be warranted.  

Researchers report in the Journal of Clinical Oncology that 3 years after WBI followed by a tumor bed boost, outcomes with hypofractionation and conventional fractionation appear to be similar.1 Simona Shaitelman, MD, EdM, University of Texas MD Anderson Cancer Center, Houston, Texas, and colleagues looked at 286 women with early-stage invasive breast cancer and found that tumor bed boost, chemotherapy, and larger breast size were not strong contraindications to HF-WBI.

The researchers conducted a randomized, multicenter trial between 2011 and 2014. They compared conventionally fractionated whole-breast irradiation (CF-WBI; 50 Gy/25 fx + 10 to 14 Gy/5 to 7 fx) to HF-WBI (42.56 Gy/16 fx + 10 to 12.5 Gy/4 to 5 fx). All the women had stage 0 to stage II breast cancer and were randomly assigned to receive CF-WBI or HF-WBI. The women were stratified by chemotherapy, margin status, cosmesis, and breast size.

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Among the 286 patients, 30% received chemotherapy, and 36.9% were categorized as having a large breast size. The researchers found that 3-year adverse cosmetic outcome was 5.4% lower with HF-WBI (8.2% versus 13.6% with CF-WBI). Adverse cosmetic outcomes were higher by 4.1% with HF-WBI than with CF-WBI in the patients treated with chemotherapy. Among women with large breast size, adverse cosmetic outcome was 18.6% lower with HF-WBI.

The researchers also found poor or fair photographically assessed cosmesis occurred in 28.8% of CF-WBI patients compared with 35.4% of HF-WBI patients. The 3-year local recurrence-free survival rates were equal between cohorts (99%).                                                                

Reference

  1. Shaitelman SF, Lei X, Thompson A, et al. Three-year outcomes with hypofractionated versus conventionally fractionated whole-breast irradiation: results of a randomized, noninferiority clinical trial. J Clin Oncol. 2018;36(35):3495-3503.