Postmastectomy Radiation Therapy for Locoregional Control of Breast Cancer
Posted: Thursday, May 10, 2018
Although postmastectomy radiation therapy seemed to improve locoregional recurrence in women with T1–T2 tumor and up to three positive lymph nodes, the 10-year rates of locoregional recurrence were relatively low compared with historical studies. Youssef H. Zeidan, MD, PhD, of the American University of Beirut, and colleagues, who published these findings in the International Journal of Radiation Oncology • Biology • Physics, suggest the decision to deliver postmastectomy radiation therapy to women with up to three positive nodes should be tailored to individual patient risks.
According to the investigators, radiation therapy after mastectomy for this patient population with breast cancer has been controversial. Although there were a low number of events in this trial, these study results show postmastectomy radiation therapy may further improve locoregional recurrence outcomes, although there was no “significant impact on overall survival or breast cancer–specific survival.”
In their analysis, women with pathologic stage T1–T2 tumors and one to three positive lymph nodes enrolled in the phase III BIG 02-98 trial were followed for 10 years. Of the 684 patients evaluated, 337 (49%) received radiation therapy after mastectomy and axillary node dissection.
The risk of locoregional recurrence was 2.5% with postmastectomy radiation therapy versus 6.5% in those without. Women who received adjuvant chemotherapy with no taxane obtained an “incremental benefit” with postmastectomy radiation therapy, with the locoregional recurrence rate being 3.4% (versus 9.1% without postmastectomy radiation therapy); among those who received taxane-based adjuvant therapy, the rate was 2.0% versus 5.3% with and without postmastectomy radiation therapy, respectively.