Breast cancer is the second most frequently diagnosed cancer for American women and nearly 40% have mastectomies. The majority who do undergo reconstructive breast surgery.
To help prevent their cancer from returning, most patients who get mastectomies also receive radiation therapy to the chest wall and lymph nodes over a period of five to six weeks. The new research finds that a shorter course of treatment is just as effective at preventing the cancer from returning and can improve patients’ quality of life.
Scanning electron microscope images shows breast tumor cell (pink) on a thick layer of Matrigel (green), which mimics the basement membrane separating the body’s tissues. Image credit: Renaud Poincloux&Philippe Chavrier/CNRS/Institut Curie Thanks to the Ultrastructural Microscopy Group of the Institut Pasteur
The large, phase III RT CHARM trial (Alliance A221505) included 898 patients with unilateral invasive breast cancer at 209 academic and community-based cancer centers across the U.S. and Canada. Eligible patients included those with larger tumors (pT3N0) or smaller tumors and invasion of the regional lymph nodes (pT0-2 pN1-2). The median patient age was 46 years, and all patients were planning immediate or delayed breast reconstructive surgery following post-mastectomy radiation.
Patients were randomized to receive either conventional radiation consisting of 25 fractions delivered across five weeks (50 Gy total; n=449) or hypofractionated radiation consisting of 16 fractions delivered across roughly three weeks (42.56 Gy total; n=449). Slightly more than half of the patients (51%) received chemotherapy prior to their mastectomies, and 37% received chemotherapy following mastectomy.
Among the 650 patients who completed reconstruction during the study period, 59% had implants alone and 41% had autologous reconstruction using their own tissue, with or without implants. Researchers followed these patients to document any reconstruction complications, including issues with wound healing, hospital readmission, unplanned re-operation, reconstruction failure or capsular constructure, which involves scar tissue affecting the new breast. The median follow-up was five years.
Two years after reconstructive surgery, 14% of patients who had the shorter course of radiation experienced complications, compared to 12% of those who had the standard course of treatment. This difference was considered statistically non-inferior (Z=3.373, p=0.0004). Treatment-related side effects were equally mild for both groups, occurring for fewer than 6% of patients on either treatment arm.
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