After a response to initial chemotherapy, treatment with radiotherapy and surgical removal of the breast tumor and nearby lymph nodes do not provide any additional benefit to patients with metastatic breast cancer, according to results of a clinical trial presented here at the 2013 San Antonio Breast Cancer Symposium, held Dec. 10-14.
"There is a small percentage, about 5 to 20 percent of breast cancer patients, who present with metastatic breast cancer when they see their doctors for the first time, and across the globe, the thought is that the local tumor in such events does not require any surgery or radiation [known as loco-regional treatment (LRT)] after chemotherapy, unless there is bleeding or ulceration," said Rajendra Badwe, M.D., director of the Tata Memorial Hospital in Mumbai, India. "However, there are conflicting results from retrospective analyses, and hence, there was a need for a randomized trial.
"We found that there was no difference in overall survival between those who received LRT and those who did not receive LRT," explained Badwe. "Indeed, there was a 7 percent excess death rate in those who received LRT. This finding was not statistically significant; nevertheless, it aligns with previous preclinical findings that suggest surgical removal of the primary tumor bestows a growth advantage on metastases.
"I'm sure a lot of oncologists who believe in conventional wisdom and don't provide loco-regional treatment will feel a lot more comfortable looking at these results," said Badwe. "As for those who have changed practice based on the retrospective study history, they would have to rethink."
Badwe and colleagues conducted a prospective, randomized, controlled trial, to which they recruited 350 women between 2005 and 2013. Eligible patients had metastatic breast cancer and an objective tumor response to six cycles of chemotherapy. Patients were randomized to two arms: 173 women received LRT (LRT arm) and 177 women received no LRT (no-LRT arm). Both arms were matched for age, clinical tumor size, hormone receptor and HER2 receptor status, and status of disease spread.
Patients in the LRT arm underwent partial or complete surgical removal of their breasts and surgical removal of axillary lymph nodes, followed by radiotherapy. Patients in the no-LRT arm did not receive any surgery or radiotherapy. Patients from both arms whose breast cancers were hormone-related received standard hormone therapy. The primary endpoint of the study was overall survival. Nine patients from the LRT arm and three patients from no-LRT arm could not adhere to trial protocol.
During the median follow-up period of 17 months, the investigators recorded 218 deaths, 111 from the LRT arm and 107 from the no-LRT arm.
They found that the median overall survival in the LRT and no-LRT arms were 18.8 months and 20.5 months, respectively. Overall survival after two years of follow-up was 40 percent in the LRT arm and 43.3 percent in the no-LRT arm. No difference in overall survival between the two arms emerged, even after adjusting for age, hormone receptor and HER2 receptor status, site of disease spread, and number of tumors in organs other than the indicated breast.