PHILADELPHIA (October 19, 2015) – In the biggest study to date evaluating patients with nonmetastatic, large, invasive breast cancers, survival rates were found to be similar for patients treated with either breast conservation surgery and radiation, or mastectomy, according to an analysis published in Cancer.
“For decades, breast cancers have been felt to be amenable to lumpectomy with radiation only if the tumors were 5 centimeters, or smaller. This is because the prospective trials that compared the two surgery types didn’t enroll patients whose tumors were larger than 5 centimeters,” said lead investigator Richard J. Bleicher, MD, Department of Surgical Oncology at Fox Chase Cancer Center – Temple Health. “Since there are no clinical trials evaluating breast conservation therapy versus mastectomy for tumors over 5 centimeters, breast conservation is still considered relatively contraindicated in current guidelines.”
“This study, the largest of its kind, demonstrates that women who are felt to be amenable to resection by their surgeons can have a lumpectomy and radiotherapy to the breast and have an equivalent outcome as mastectomy,” he said.
Dr. Bleicher and his colleagues at Fox Chase reviewed the Surveillance Epidemiology and End Results (SEER)-Medicare-linked database with information about breast cancer diagnosis and treatment. The database includes information on 5,685 patients with tumors larger than 5 centimeters who underwent breast surgery between 1992 and 2009; 887 of those patients, or 15.6 percent, had been treated with breast conservation surgery instead of mastectomy. The analysis found that the adjusted overall survival and breast cancer-specific survival rates were equivalent between breast conservation and mastectomy.
While each treatment type individually showed how overall survival and disease-specific survival improved over time, the overall survival and disease-specific survival rates for patients with these larger tumors remained equivalent between the two treatments throughout the period of study. Median follow-up was 7 years.
The analysis found that the largest predictors of breast conservation therapy use among those in the database included neoadjuvant chemotherapy and postoperative radiotherapy, higher patient income, and history of a prior non-breast malignancy. The largest predictors of mastectomy use included stage III disease, younger age at diagnosis, Asian race, greater number of positive lymph nodes, and treatment in a less urban/rural metropolitan area.
“Many surgeons may not do breast conservation for patients with large tumors, even when their breast size is generous enough to accommodate such a large tumor removal,” Dr. Bleicher said. “We now have data demonstrating that breast conservation appears safe and should remain an option when the surgeon feels that the patient’s breast size can accommodate the resection.” The use of breast conservation surgery has increased in recent years, but no prospective clinical trials have permitted breast conservation for tumors larger than 5 centimeters. Published series have shown that the therapy is used occasionally for some of these larger tumors in both the adjuvant and neoadjuvant setting, the researchers noted.
Beyond the probability of equivalent survival rates, there also may be important psychological considerations for breast conservation, the researchers said. Previous data have demonstrated a correlation between breast conservation therapy and an improved quality of life due to body image and treatment satisfaction. “Our data reinforces the notion that the option should be provided to all those clinically amenable to local resection,” they said.