SAN DIEGO – More women with triple negative breast cancer are able to have breast-conserving therapy (BCT) when they receive neoadjuvant systemic chemotherapy.
In a recent trial, 42% of women who were considered ineligible for BCT became eligible for the tissue-sparing surgery after their course of neoadjuvant chemotherapy (NACT) was administered. However, surgeons and patients must work together to decide on the best course of action, according to Dr. David Ollila of the University of North Carolina, Chapel Hill.
The relationship between NACT and the option to have breast-sparing surgery had not been well understood previously, especially for women with aggressive triple negative breast cancer, Dr. Ollila said at the annual meeting of the American Surgical Association.
What has been known is that women with breast cancer who receive NACT show overall improved pathological complete response (Lancet 2014;384:164-72), which is associated with better event-free and overall survival.
The current study, conducted within the larger CALGB 40603 randomized phase II clinical trial, captured the number of patients who converted from BCT-ineligible to BCT-eligible after NACT and before surgery. Investigators also tracked pathological complete response, defined as tumor-free margins on pathologic examination, for those receiving each type of surgery. Dr. Ollila presented his findings on behalf of his coinvestigators in the Alliance for Clinical Trials in Oncology.
The study used a 2x2 factorial design to compare paclitaxel with and without carboplatin followed by doxorubicin plus cyclophosphamide with and without bevacizumab. Before NACT, the surgeon determined whether or not the patient was a candidate for BCT and if not, why not. The process was repeated after NACT, with the surgeon again documenting his or her reasoning for the choice.
Complete data were available for 404 women, distributed evenly across chemotherapy treatment arms. Before NACT, 219 (54%) were judged by their surgeons to be BCT candidates, and 197 (90%) were still deemed eligible for BCT after NACT. Of the 185 (46%) judged ineligible for BCT before chemotherapy, 72 (42%) became eligible for tissue sparing surgery after NACT. “We achieved a very high conversion rate ... from BCT ineligible to eligible,” Dr. Ollila noted.
Overall, just over two-thirds of the 404 women (n = 275, 68%) became candidates for BCT before surgery, and of those, about two-thirds (n = 191, 69%) went on to have an attempted BCT surgery. Surgery was successful for 178 of these women. “Neoadjuvant chemotherapy led to BCT in 93% of selected triple negative patients,”said Dr. Ollila.
Pathological complete response did not differ significantly among the women who received BCT or mastectomy, whether the decision was made before or after chemotherapy.
Discussant Dr. Lisa Newman of the University of Michigan observed that NACT allows some breathing space for the patient and her surgeon to weigh choices, and when indicated, to receive genetic testing.
“We know from numerous population-based and institutional studies that many are opting for bilateral mastectomy, even if a lumpectomy would be optimal,”said Dr. Newman.
She asked whether patient decision making was tracked for this study. Dr. Ollila replied, “We did not include patient factors. We do not have prospective data on what the patient was thinking because we focused on the surgeon.” However, he said, plans are underway to quantify the patient perspective during the decision-making process.
The takeaway message, said Dr. Ollila, is that “We are letting people think that mastectomy is the best option; I think that sequential surgery is all right. I think we just need to try breast conserving therapy more often than we are.”
The study was partially sponsored by the Breast Cancer Research Foundation. The authors reported no conflicts of interest.
The complete manuscript of this study and its presentation at the American Surgical Association’s 135th Annual Meeting, April 2015, in San Diego, California, are anticipated to be published in the Annals of Surgery pending editorial review.