Radiation treatment have a wide variability following neoadjuvant chemotherapy (NAC) and surgery for breast cancer, according to a review of the American College of Surgeons Oncology Group (ACOSOG) Z1071, a prospective trial.
A multi-center phase II trial, ACOSOG Z1071 evaluated the false negative rate of sentinel lymph node (SLN) surgery after NAC (chemotherapy delivered prior to treatment to shrink the tumor) in breast cancer patients.
After receiving chemotherapy, 58.5 percent patients remained node-positive while 41.5 percent changed to node-negative. Of 401 node-positive patients, mastectomy was performed in 148 (36.9 percent), mastectomy with immediate reconstruction in 107 (26.7 percent) and breast-conserving surgery (BCS) in 146 patients (36.4 percent).
Most patients received RT, regardless of the surgical treatment of the primary tumor following NAC. Post-mastectomy RT was more frequently omitted after reconstruction than mastectomy (23.9 percent vs 12.1 percent, respectively, P=.002) and was omitted in 19 of 107 patients (17.8%) with residual node-positive disease in the reconstruction group.
The use of internal mammary RT was low, between 7.8 percent and 11.2 percent, and did not differ with surgical approaches. The rate for supraclavicular RT ranged from 46.6 percent to 52.2 percent, and was omitted in 193 node-positive patients (47.3 percent). Some of the observed variations reflect ongoing unresolved controversies in the field of radiation therapy.
In patients who converted to node negative following NAC, and were treated with breast conserving surgery and radiation, regional nodal radiation was employed in approximately half the patients and omitted in half the patients, reflecting the need for more guidance, an issue that is currently being addressed in a randomized national trial, NRG-B51.
"Patient and physician treatment decisions have been impacted by the increasing use of NAC," said Bruce G. Haffty, MD, Interim Director Rutgers Cancer Institute of New Jersey and Department Chair of Radiation Oncology, Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey, lead author of the study. Dr. Haffty is also immediate Past Chair of the American Society for Radiation Oncology (ASTRO).
"This study revealed wide variability in practice, particularly regarding administration of radiation therapy and field design following NAC and surgery for breast cancer."
"Discussion and collaboration among all of the members of a multidisciplinary team of medical oncologists, surgical oncologists and radiation oncologists is important for optimal management," Dr. Haffty said.
"The study also emphasizes the importance of the ongoing national clinical trials regarding local-regional management of breast cancer after NAC," he said. "Specifically, the NRG B51 trial and the Alliance A011202 trial both address important aspects of local-regional treatment and will help to provide guidance on how to best approach local-regional management after neoadjuvant chemotherapy."