Hypofractionated whole-breast irradiation equivalent to conventional therapy in early stage disease, study suggests

Equivalent pain, functional and cosmetic outcomes have been reported by early-stage breast cancer patients receiving hypofractionated whole-breast irradiation compared to patients undergoing conventionally fractionated whole-breast irradiation, according to a new study.

The prospective, unblinded study, published recently in Cancer, was carried out by Cameron Swanick and colleagues at the University of Texas MD Anderson Cancer Center (TX, USA), and included 287 women with stage 0–-II breast cancer.

Of the 287 patients, 149 received conventionally fractionated whole-breast irradiation, at a dose of 50 grays in 25 fractions, while the other 138 patients received hypofractionated whole-breast irradiation (HF-WBI), at a dose of 42.56 grays in 16 fractions; both cohorts received a tumor bed ‘boost dose’.

All study participants were at least 40 years of age and had undergone breast-conserving surgery. Body mass index evaluations of the study cohort indicated that 76% were overweight or obese.

Using the Breast Cancer Treatment Outcome Scale, the Functional Assessment of Cancer Therapy-Breast Trial Outcome Index score and the Body Image Scale (recorded at baseline and 0.5, 1, 2, and 3 years after radiotherapy), researchers were able to assess patient’s functional and pain outcomes in addition to physician-rated cosmesis.

Lead author Cameron Swanick commented: “There were no significant differences between the treatment arms for any patient-reported outcomes at baseline, 6 months, 1 year or 3 years. At 2 years, outcomes from the Functional Assessment of Cancer Therapy Breast trial outcome index were modestly higher in the hypofractionated group.”

Despite HF-WBI having a shorter, more convenient schedule and it being regarded as a safe and effective treatment option in the UK and Canada, it is still rarely used in the USA. Swanick and his colleagues hope that this study in conjunction with others will support the use of HF-WBI as the preferred treatment choice for early-stage breast cancer patients in the USA.

“This trial is particularly important because there is still some hesitation among clinicians in the US about adopting the hypofractionated schedule. Because American patients tend to have a higher prevalence of obesity and because prior trials excluded certain patients with high body mass index, there has been this concern that the shorter radiation treatment course may not be as safe for American patients,” Swanick reported.

Benjamin Smith, Associate Professor of Radiation Oncology (MD Anderson Cancer Center) explained: “At MD Anderson these shorter courses have become the standard of care.” Smith believes that the results of this study, combined with those of previous investigations, further support the use of HF-WBI as the preferred radiation therapy for early-stage breast cancer patients.

Sources: Swanick CW, Lei X, Shaitelman SF et al. (2016), Longitudinal analysis of patient-reported outcomes and cosmesis in a randomized trial of conventionally fractionated versus hypofractionated whole-breast irradiation. Cancer. Doi: 10.1002/cncr.30121 (2016); MD Anderson Cancer Center press release