Women with big breasts have safer RT in prone position than supine position; JAMA

A new study published in the Journal of American Medical Association suggests that treatment in the prone posture reduces desquamation in women undergoing adjuvant radiation who have big breasts (RT).

Women with big breasts who get adjuvant breast radiation (RT) have a significant incidence of skin toxicity. One option for reducing these harmful effects is to do breast RT in the prone position. As a result, Danny Vesprini and colleagues undertook this investigation to see how prone breast RT minimizes immediate toxic effects on the skin when compared to supine therapy.

From April 2013 to March 2018, this phase 3, single-blind, randomized, multicenter clinical study included patients from 5 sites throughout Canada to investigate the acute toxic effects of breast RT for women with big breast size (bra band 40 in and/or D cup) in the prone versus supine positions. A total of 378 individuals were referred for adjuvant RT and randomly assigned. Seven patients were eliminated from the supine position, while 14 patients were excluded from the prone position. The data was examined from April 2019 to September 2020. Patients were randomly assigned to either supine or prone RT. All patients (n = 167) got 50 Gy in 25 fractions (extended fractionation) with or without boost from April 2013 to June 2016. (range, 10-16 Gy). Following the June 2016 trial modification, the majority of patients got the hypofractionation schedule of 42.5 Gy in 16 fractions.

The key findings of this study were as follow:

1. Of the 357 women studied, 182 (51.0%) were treated supine and 175 (49.0%) were treated prone.

2. Patients treated in the supine position had statistically substantially higher desquamation than those treated in the prone position, which was supported by multivariable analysis, along with other independent covariates such as boost usage, prolonged fractionation, and bra size.

In conclusion, according to a phase III randomized experiment, breast irradiation in the prone position is less harmful than in the supine position in women with big breast size.

Reference:

Vesprini D, Davidson M, Bosnic S, et al. Effect of Supine vs Prone Breast Radiotherapy on Acute Toxic Effects of the Skin Among Women With Large Breast Size: A Randomized Clinical Trial. JAMA Oncol. Published online May 26, 2022. doi:10.1001/jamaoncol.2022.1479