Hypofractionated Whole-Breast Irradiation Benefits Early-Stage Breast Cancer Patients

The use of hypofractionated whole-breast irradiation (HF-WBI) for patients with early-stage breast cancer increased 17.4% from 2004 to 2011, and patients are more likely to receive HF-WBI compared to traditionally fractionated whole-breast irradiation (CF-WBI) when they are treated at an academic center or live ≥ 50 miles away from a cancer center, according to new findings.

The study was published December 1, 2014, in the International Journal of Radiation Oncology • Biology • Physics (Red Journal), the official scientific journal of the American Society for Radiation Oncology (ASTRO). An analysis of randomized trials revealed that patients with early-stage breast cancer who are treated with breast-conserving surgery and adjuvant whole-breast irradiation have improved survival and a lower risk of tumor recurrence compared to patients who are not treated with radiotherapy.

Patients are typically treated with CF-WBI; however, several recent randomized trials have confirmed that patients treated with HF-WBI have comparative disease-free and overall survival rates as those treated with CF-WBI. CF-WBI delivers a total dose of 45–50 Gy in 25–28 daily fractions of 1.8–2.0 Gy over five to six weeks, while HF-WBI uses a shorter treatment course and a lower total dose and number of fractions, delivering a total dose of 39–42.5 Gy in 13–16 daily fractions of 2.5–3.2 Gy over three to five weeks.

This study is a retrospective review of 113,267 early-stage breast cancer patients in the US National Cancer Data Base (NCDB) from 2004 to 2011 who were treated with radiation therapy and were eligible to receive HF-WBI, and examines the use of HF-WBI compared to CF-WBI and the factors, including facility type and patient’s distance from the radiation treatment center, that influenced which type of WBI the patient received.

The NCDB, a joint program of the American College of Surgeons’ Commission on Cancer and the American Cancer Society established in 1989, is a US facility-based data set that contains retrospective data on 70% of all newly diagnosed tumors in the United States. The study, conducted by researchers from the Yale School of Medicine (New Haven, CT, USA) and Rutgers Cancer Institute of New Jersey and Robert Wood Johnson Medical School (New Brunswick, NJ, USA), identified data from early-stage breast cancer patients included in the NDCB from 2004 to 2011 who received adjuvant WBI and who were eligible to receive HF-WBI according to current guidelines and randomized trials.

Eligible patients were age 50 or older at the time of diagnosis; had a first and only diagnosis of breast cancer; had pathologic stage T1-2 N0 breast cancer, based on the American Joint Committee on Cancer TNM staging classification; were treated with breast-conserving surgery; and did not receive chemotherapy. In this study, HF-WBI was defined as a fraction dose of ≥ 2.2 Gy and ≤ 4.0 Gy, and CF-WBI was defined was a fraction dose > 1.5 Gy and < 2.2 Gy. Regional radiation therapy total dose was limited to 40-66.4 Gy, and boost doses were limited to < 21.6 Gy.

Related Links:
Yale School of Medicine
Robert Wood Johnson Medical School