SAN FRANCISCO – Breast cancer surgery within 30 days of neoadjuvant chemotherapy appears to be safe, with no significant increase in risk of postoperative complications compared with surgery performed in women who did not receive chemotherapy.
An analysis of data on more than 3,500 patients who underwent surgery for invasive breast cancer after receiving neoadjuvant chemotherapy showed that in an analysis adjusted to better balance patient characteristics, there were no significant differences in postoperative complication rates for patients who received chemotherapy and those who did not, reported Dr. Erin Cordeiro from the Ottawa Hospital in Ontario, Canada, and associates, at a breast cancer symposium sponsored jointly by the American Society of Clinical Oncology, American Society for Radiation Oncology, and Society of Surgical Oncology.
Dr. Erin Cordeiro
“I really think this should put to rest the concern that surgeons might have about neoadjuvant chemotherapy particularly because this [study] compressed people within 30 days of the surgery date,” commented Dr. Charles E. Geyer, Jr., from the Virginia Commonwealth University School of Medicine in Richmond. Dr. Geyer was the invited discussant.
The use of neoadjuvant chemotherapy in the treatment of patients with breast cancer continues to increase, growing from 14% in 2006, to 20% in 2011, Dr. Cordeiro said.
But because myelosuppression, particularly neutropenia, is a common side of chemotherapy, surgeons are often concerned that operating too soon after a patient completes a course of chemotherapy could result in increased post-operative complications, she said.
To determine whether neoadjuvant chemotherapy would increase the proportion of overall 30-day postoperative complications among patients undergoing surgery for invasive breast cancer, Dr. Cordeiro drew on the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database, which contains validated, risk-adjusted surgical outcomes data from more than 600 hospitals in 49 states, Canada, and Europe.
Dr. Charles E. Geyer
She identified data on 67,685 patients who underwent surgery for invasive breast cancer from 2005 through 2012. Of this group, 3,624 (5.5%) had received neoadjuvant chemotherapy. Investigators excludedpPatients with high-risk comorbidities and those who underwent other surgery concurrent with breast surgery (e.g., oophorectomy).
In unadjusted analysis, the rate of a composite of overall 30-day post-operative complications, the primary outcome, was 4.9% for patients who had undergone neoadjuvant chemotherapy, compared with 3.7% for patients who did not and this difference was significant (P= .0003). The higher rate among patient who had received chemotherapy recently was largely due to infections, Dr. Cordeiro said.
However, in a multivariate analysis adjusted for propensity score – a measure of the probability of receiving neoeadjuvant chemotherapy by age, diabetes, chronic obstructive pulmonary disease, hypertension, bilateral surgery, and/or year of surgery – the differences between patients who underwent neoadjuvant chemo and those who did not vanished (odds ratio 1.16; 95% confidence interval, 0.98-1.36).
Dr. Cordeiro acknowledged that the study was limited by the use of retrospective data, a lack of knowledge of exactly when chemotherapy was stopped in relation to the surgery data, lack of data on which regimens were used, and no information about prophylatic antibiotics or thromboprophylaxis.
The investigators plan to perform additional subgroup analyses to determine whether there might be differences in complication rates in patients who did or did not receive neoadjuvant chemo by type of breast surgery (breast-conserving vs. mastectomy), type of axillary surgery (sentinel node biopsy vs. axillary lymph node dissection) or among patients who undergo immediate reconstruction.
The study was presented as a poster and in an oral abstract session.