A radiation schedule half the standard course is as safe and effective for patients with breast cancer following a mastectomy, according to a study published in the Journal of Clinical Oncology (published online May 1, 2017; doi:10.1200/JCO.2016.70.7158).
Patients who undergo a mastectomy and may be at risk for remaining cancer cells in the chest wall and lymph node regions are often given targeted radiation over a 5 to 6-week period. However, receiving radiation for that long may impact the quality of life for such patients. Data supporting hypofractionated post-mastectomy radiation therapy is limited.
Bruce G Haffty, MD, professor and chair, department of radiation oncology, Rutgers Cancer Institute (NJ), and colleagues conducted a prospective analysis of short course post-mastectomy radiation therapy, in which therapy was completed in 3 weeks, rather than 5 to 6 weeks. Researchers sampled 67 patients from 2010 to 2014 with stage 3 to 3a breast cancer. Patients were given 11 fractions (3.33 Gy) in 11 days over a 3-week period. The treatment also allowed for an optional 4 fractions to the chest wall at the mastectomy scar area, resulting in a total of 15 treatments over 3 weeks. The primary endpoint was freedom from any grade 3 or higher toxicities.
After a median follow-up of 32 months, there were no reported grade 3 toxicities and 29 reported grade 2 toxicities, with a majority being skin rash followed by fatigue. Three-year estimated local recurrence-free survival was 89.2% (95% CI, 0.75-0.96) and 3-year estimated distant recurrence-free survival was 90.3% (95% CI, 0.80-0.96).
"While shorter courses of radiation therapy have been adopted in patients receiving radiation therapy to the breast alone after lumpectomy, there has not been adoption of shorter courses of treatment to the chest wall and lymph nodes after mastectomy. This trial demonstrated the safety of this shorter course approach in a prospective phase II study," noted Dr Haffty in a press release (May 2, 2017).
On the basis of this data, researchers have designed a larger, randomized, phase 3 trial, in which a similarly short course of radiation in the post-mastectomy, post-reconstruction setting will be compared with the conventional course of radiation treatment. — Zachary Bessette