A recent comparative effectiveness study examined long-term survival outcomes for patients with multiple stages of breast cancer after undergoing either mastectomy or breast-conserving surgery, published in the Journal of Global Oncology (August 2017;3[4]:304-313).
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In recent years, clinical trials have provided evidence of comparable overall survival (OS) rates in patients with breast cancer after mastectomy or breast-conserving surgery. However, the latest study to examine these two surgical procedures found one procedure to offer favorable OS over the other in patients with both stage II and stage III disease.
A group of Indian researchers led by Ambakumar Nandakumar, National Cancer Registry Program, Bangalore, Karnataka, conducted a study to compare the long-term survival results of 7609 patients with breast cancer after undergoing either mastectomy or breast-conserving surgery. Patients were treated at any of nine cancer institutions from 2006 to 2008 and were stratified by cancer stage (II or III).
Results of the comparison showed that overall 5-year survival rates were significantly improved in patients with stage II disease who underwent breast-conserving surgery compared with those who opted for mastectomy (94.0% vs 85.8%, respectively; HR, 2.40; 95% CI, 1.8-3.2). Similarly, patients with stage III breast cancer benefited from improved 5-year OS rates after breast-conserving surgery vs mastectomy (87.1% vs 69.0%, respectively; HR, 2.82; 95% CI, 2.2-3.7).
Researchers also observed that patients who underwent mastectomy demonstrated improved OS with when treated with systemic therapy, including chemotherapy alone or in combination with hormone therapy. On the contrary, patients who underwent breast-conserving surgery had optimal OS when receiving radiation therapy alone.
In their concluding remarks, researchers asserted that mastectomy in a natural setting for patients with stage II or III breast cancer is significantly less effective than breast-conserving surgery. Further research is needed to gain a better understanding of the reasons for these differences in long-term survival and to explain the rationale of the necessity of systemic therapy to achieve optimal survival in patients undergoing mastectomy but not in those undergoing breast-conserving surgery, they concluded.—Zachary Bessette
