THURSDAY, Dec. 6 (HealthDay News) -- In women with breast cancer that has recurred but remains confined to in or near the breast, post-surgical chemotherapy appears to boost survival, new research shows.

The study also found that patients with estrogen receptor (ER)-negative breast cancers -- tumors that are not reliant on estrogen -- were most responsive to this treatment.

It's well known that patients who experience a recurrence of local and/or regional (for example, nearby lymph nodes) breast cancer are at high risk for having their cancer spread to other areas of the body.

Some doctors administer chemotherapy to these patients after their recurrent breast tumors have been removed by surgery, but the efficacy of this treatment -- called adjuvant chemotherapy -- had not been studied until now.

"This is the first randomized controlled study that shows that adjuvant chemotherapy works in these patients," study author Dr. Stefan Aebi, head of the division of medical oncology at Luzerner Kantonsspital in Luzern, Switzerland, said in an American Association for Cancer Research news release.

The study was to be presented Thursday at the 2012 San Antonio Breast Cancer Symposium.

The study included 162 patients with isolated local and regional breast cancer recurrence: 85 received adjuvant chemotherapy and 77 did not.

According to the authors, five-year rates of disease-free survival (meaning the cancer did not return) were 69 percent in patients who got adjuvant chemotherapy compared to 57 percent for those who did not.

The overall survival rate was 88 percent for those who received adjuvant chemotherapy and 76 percent for those who did not.

Women with ER-negative breast cancer had the best results, with a five-year disease-free survival rate of 67 percent for those who received adjuvant chemotherapy and 35 percent for those who did not. Overall survival rates were 79 percent for those who received adjuvant chemotherapy and 69 percent for those who did not.

Among patients with ER-positive breast cancer (tumors that respond to estrogen), five-year, disease-free survival was 70 percent for those who received adjuvant chemotherapy and 69 percent for those who did not, the researchers said. Overall survival was 94 percent for those who received chemotherapy versus 80 percent among those who did not.

Although the study showed an association between adjuvant chemotherapy and improved survival, it did not prove a cause-and-effect link.

Two breast cancer experts were heartened by the results.

"There has been no clear way to manage locally recurrent breast cancer after excision -- most often, chemotherapy has been offered, but some patients have been hesitant about undergoing such aggressive therapy without known clear benefits," explained Dr. Stephanie Bernik, chief of surgical oncology at Lenox Hill Hospital in New York City.

Bernik said that, "It is exciting that we now have a randomized study that quantifies the benefit of chemotherapy for those with recurrent disease so that the patient can make an informed decision as to whether or not to go forward with the treatment. Clinicians now have a study to support what we have long held to be [that] chemotherapy can help improve survival even in woman with recurrent disease."

Dr. Kerin Adelson, an assistant professor of medicine at Mount Sinai School of Medicine, also in New York City, agreed.

"Local recurrences of breast cancer in breast tissue often near the site of the original cancer or in the axillary lymph nodes are curable, unlike cancer which returns in a distant organ," Adelson explained. "This [new] data is absolutely consistent with what we know about the benefit of systemic chemotherapy after a primary cancer. Going forward, oncologists should not hesitate to treat local recurrences as aggressively as they would a primary cancer."

More information

The U.S. National Cancer Institute has more about breast cancer treatment.