(ChemotherapyAdvisor) – Too few women with breast cancer who respond to neoadjuvant therapy are offered breast-conserving surgery, according to data from the NeoALTTO trial reported during the European Society for Medical Oncology 2012 Congress in Vienna, Austria.

The NeoALTTO trial found that in patients with HER2-positive breast cancer, treatment with paclitaxel plus lapatinib and trastuzumab resulted in a pathological complete response (pCR) rate of 51.3% compared to treatment with paclitaxel combined with either lapatinib (29.5%) or trastuzumab (24.7%). However, the high rate of pCR did not translate into a higher rate of breast-conserving surgery, approximately 40% across the three arms, Dr. Carmen Criscitiello from the European Institute of Oncology in Milan, Italy, and colleagues stated.

They investigated the association between achieving pCR by analyzing type of surgery, age, histology, grade, tumor size, ER status, multicentricity, response to therapy, and country in which the patients received treatment.

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Of 429 patients eligible for the analysis, 160 (37%) had achieved a pCR, Dr. Criscitiello stated. A total of 242 (57%) patients underwent mastectomy and 187 (43%), breast-conserving surgery.

Mastectomy was more frequently used if the patient was less than 50 years of age, treated in a developing country, or if the tumor was multicentric, >5 cm, or ER-negative. Of 68 patients who attained a radiological complete response, 36 (53%) had a mastectomy; of these, 25 (70%) had achieved a pCR.

“All patients diagnosed with lobular cancer (n=17) underwent mastectomy regardless of pCR,” they reported. Of 128 patients considered for breast-conserving surgery at screening, only 95 (74%) had conservative surgery; rates were similar according to pCR status (79% in pCR vs 72% in no pCR). Conversely, 30% of patients initially evaluated as inoperable or requiring mastectomy had breast-conserving surgery.

“Tumor characteristics prior to neoadjuvant therapy appeared to play a main role in deciding the type of surgery irrespective of response,” Dr. Criscitiello noted. “This study highlights a negative attitude that may deny a large fraction of women the chance of preserving their breast, with no clinical reasons that justify this decision. One of the goals of the neoadjuvant therapy concerns increasing the rate of breast conservation, but this goal is clearly not achieved if the type of surgery is chosen according to baseline characteristics.”

Dr. Criscitiello and colleagues call for a clear consensus in the role of breast conserving surgery for patients responding to neoadjuvant therapy. “This will translate the progress in neoadjuvant therapies and the consequent high pathological complete response rates into higher rates of breast conservation,” they noted.