December 16, 2014 — A new study on the use of hypofractionated whole-breast irradiation (HF-WBI) for early-stage breast cancer patients found HF-WBI increased 17.4 percent from 2004 to 2011. Patients are also more likely to receive HF-WBI compared to conventionally fractionated whole-breast irradiation (CF-WBI) when they are treated at an academic center or live ?50 miles away from a cancer center. The study was published in the Dec. 1, 2014, issue of 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 demonstrated 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 radiation therapy.
Patients are commonly treated with CF-WBI; however, several recent randomized trials have confirmed that patients treated with HF-WBI have similar 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—a total dose of 39-42.5 Gy is delivered in 13-16 daily fractions of 2.5-3.2 Gy over three to five weeks.
This study, “Adoption of Hypofractionated Whole-Breast Irradiation for Early-Stage Breast Cancer: A National Cancer Data Base Analysis,” is a retrospective review of 113,267 early-stage breast cancer patients in the National Cancer Data Base (NCDB) from 2004 to 2011. It 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 study 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.
Patients who received regional nodal radiation therapy; who received brachytherapy, stereotactic radiation therapy and treatments delivered with electron, neutron or proton beams; who received fewer than 10 or more than 50 fractions; or who received radiation therapy as palliative care were not included in the analysis.
The study also examined factors that may have influenced whether a patient received HF-WBI or CF-WBI. Of the 113,267 patients who met the study criteria, 62.5 percent (70,801) of patients received treatment at a non-academic comprehensive community cancer center; 24.8 percent (28,137) of patients were treated at a community cancer program; 11.6 percent (13,174) of patients had treatment at an academic center; and 1 percent (1,155) of patients were treated at other types of facilities. Of the patients treated at non-academic comprehensive community cancer centers, 10.3 percent (7,313) received HF-WBI compared to 17.3 percent (4,830) of patients who had treatment at academic centers. HF-WBI was delivered to 7.7 percent (1,018) of patients treated at community cancer programs compared to the 17.3 percent (4,830) of patients treated at academic centers.
Based on the study data, distance from the cancer-reporting facility to the radiation therapy center also proved to be a factor in whether a patient received HF-WBI or CF-WBI. The NCDB data does not include the distance from a patient’s residence to the treatment center. For this study, the distance was calculated from the cancer-reporting facility to the treatment center. A distance of ?50 miles was classified as long distance. Of the eligible patients included in this study, 92.2 percent (104,442) of patients lived <50 miles from the treatment center; 4.2 percent (4,813) lived ?50 miles from the treatment center; 3.5 percent (3,996) of patients did not have distance travelled data available. HF-WBI was more frequently prescribed to patients who live ?50 miles from the treatment center (16.1 percent, n=775) compared to patients who live <50 miles from the treatment center (11.5 percent, n=11,957) (OR 1.57, 95 percent CI 1.44-1.72).
“Recently reported, long-term follow-up from randomized trials confirm that hypofractionated radiation therapy for breast cancer is equivalent to longer courses of radiation therapy. As a result, recent clinical guidelines such as ASTRO’s “Fractionation for whole-breast irradiation: An American Society for Radiation Oncology (ASTRO) evidence-based guideline” and ASTRO’s Choosing Wisely recommendations support the use of hypofractionated radiation therapy for breast cancer,” said James B. Yu, M.D., MHS, co-author of the study and assistant professor in the department of therapeutic radiology at Yale School of Medicine. hypofractionated radiation therapy for appropriate patients.”
For more information: www.astro.org