Patients with larger malignant tumors of the breast who undergo chemotherapy before breast cancer surgery are more likely to opt for a breast-preserving procedure and forgo a mastectomy, according to a new study published in the Journal of the American College of Surgeons (2015; 10.1016/j.jamcollsurg.2015.02.011).

This is one of the largest studies to date on the use of chemotherapy before surgical treatment for breast cancer. Study investigators from Yale University School of Medicine and Yale University Comprehensive Cancer Center, New Haven, Connecticut, also determined that rates of chemotherapy before breast surgeries, known as neoadjuvant therapy, had increased significantly through the 5-year study period, possibly because the FDA had approved better chemotherapy drugs.

“We’ve seen data published from clinical trials showing that neoadjuvant chemotherapy results in increased lumpectomy rates but this is really one of the first studies using a large national database that reflects what is also going on in the community hospital setting,” said lead investigator and general surgeon, Brigid K. Killelea, MD, MPH, FACS. (During a lumpectomy procedure only the tumor and surrounding tissue is removed, leaving the rest of the breast tissue intact.)

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In all, the study involved 354,204 women with invasive breast cancer who underwent breast surgeries and chemotherapy either before or after their procedures, or both, from 2006 through 2011. Out of that group, 59,063, or 16.7%, approximately 1 in 6 patients, underwent chemotherapy before their operations.

This study did not look at overall survival among women who received presurgery chemotherapy, which previously, smaller trials have found to be no different from adjuvant chemotherapy. However, it did confirm a trend that those trials had noted: higher rates of breast conservation among patients with larger tumors for those who received chemotherapy first. This Yale study found that 35% of women who received presurgery chemotherapy also had breast conservation therapy.

“One interesting thing that we saw over time was that the percentage of women that did receive neoadjuvant therapy increased, going from 13.9% to 20.5% from 2006 to 2011,” said Killelea. This is from approximately 1 in 7 women in the first year of the study to 1 in 5 in the last.

Further, women with larger breast tumors were more likely toward the end of the trial period to opt for presurgery chemotherapy and breast-sparing lumpectomy versus mastectomy, Killelea noted.

“Those who received neoadjuvant chemotherapy were 70% more likely to have a lumpectomy for tumors larger than three centimeters (approximately 1.25 inches in diameter), leading to an increased rate of breast preservation,” she said. “In other words, those people were able to avoid a mastectomy.”

Mastectomies were avoided for tumors as large as 4 to 8 centimeters, or 1.5 to approximately 3 inches in diameter, study authors noted.

Advances in chemotherapy drugs since 2006 have made these agents more effective in treating increasingly serious forms of breast cancer, such as HER2-positive and triple-negative cancers, according to Killelea. In these patients, chemotherapy before the operation gives surgeons the opportunity to evaluate how the tumor will respond to treatment.

Another advantage of presurgery chemotherapy is that doctors can begin treatment of cancer that has spread to the lymph nodes immediately rather than waiting for the breast to heal after the procedure, Killelea noted.