SOURCE: American Society for Radiation Oncology

American Society for Radiation Oncology

April 07, 2016 14:41 ET

More Guidelines, Uniformity in Radiation Decision-Making and Field Design Needed Following Neoadjuvant Chemotherapy, Surgery in Breast Cancer

FAIRFAX, VA--(Marketwired - April 07, 2016) - Wide variability exists in radiation treatment decisions 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. ACOSOG is now part of the Alliance for Clinical Trials in Oncology.

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 701 breast cancer patients with initial node-positive disease who met all eligibility requirements and underwent SLN surgery followed by completion axillary lymph node dissection (ALND). Six hundred eighty-five (685) patients enrolled in Z1071 were eligible for the current analysis, which sought to evaluate the variability of practice patterns following NAC.

The study, "Patterns of Local-Regional Management Following Neoadjuvant Chemotherapy in Breast Cancer: Results From ACOSOG Z1071 (Alliance)," was published in the March edition of International Journal of Radiation Oncology • Biology • Physics (Red Journal). Study authors focused primarily on surgical approaches, use of reconstruction after mastectomy, and use of post-mastectomy and regional nodal irradiation, nodal status and response to NAC.

After receiving chemotherapy, 401 (58.5 percent) patients remained node-positive while 284 (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). In women undergoing reconstruction, bilateral mastectomy rates were higher than in those who did not have reconstruction (66.5 percent versus 32.2 percent, respectively, < .0001).

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. "Patients should be made aware that there are various approaches to local-regional management of breast cancer after neoadjuvant systemic therapy."

"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."

For more information, contact ASTRO's Press Office at press@astro.org. To read the study, visit http://www.redjournal.org/article/S0360-3016(15)26687-4/fulltext. For more information about Red Journal, visit www.redjournal.org.

ABOUT ASTRO

ASTRO is the premier radiation oncology society in the world, with more than 10,000 members who are physicians, nurses, biologists, physicists, radiation therapists, dosimetrists and other health care professionals that specialize in treating patients with radiation therapies. As the leading organization in radiation oncology, the Society is dedicated to improving patient care through professional education and training, support for clinical practice and health policy standards, advancement of science and research, and advocacy. ASTRO publishes three medical journals, International Journal of Radiation Oncology • Biology • Physics (www.redjournal.org), Practical Radiation Oncology (www.practicalradonc.org) and Advances in Radiation Oncology (www.advancesradonc.org); developed and maintains an extensive patient website, RT Answers (www.rtanswers.org); and created the Radiation Oncology Institute (www.roinstitute.org), a nonprofit foundation to support research and education efforts around the world that enhance and confirm the critical role of radiation therapy in improving cancer treatment. To learn more about ASTRO, visit www.astro.org.

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