Midstream chemotherapy adjustment might improve breast cancer survival
SAN ANTONIO, TX - According to a new study, changing chemotherapy protocols midstream on the basis of individual patient responses to the first two cycles results in improved overall survival as well as disease-free survival rates for patients with luminal-type breast cancers. The study was presented December 8 at the 34th Annual San Antonio Breast Cancer Symposium (SABCS). Gunther von Minckwitz, MD, PhD, professor and senior physician at the Center for Gynecology and Obstetrics at the University of Frankfurt in Frankfurt, Germany and his colleagues conducted the study known as the GEPAR-TRIO (GErman Pre-operative Adriamycin and Docetaxel) trial.
Dr. Minckwitz noted that, although the regimen his team developed improved survival in patients with luminal-type breast cancers, it did not appear to benefit patients with HER2-positive or triple-negative (lacking HER2, estrogen, and progesterone receptors). He added that the trial also showed a disconnect between treatment effects and complete responses on pathology (pCR) in some disease subtypes. He said, "Interim response-guided neoadjuvant [new and supplementary] chemotherapy improved survival. Treatment effects on survival derived from luminal-type tumors. This treatment effect could not be predicted by pCR as these tumors have lower pCR rates, and their prognosis does not depend on pCR." He added that, conversely, for patients with HER2-positive or triple-negative tumors, for whom response-guided treatment was ineffective, pCR was highly prognostic.
The GEPAR-TRIO trial was designed to examine the effect of basing neoadjuvant chemotherapy choices on clinical and pathologic responses after two cycles of the TAC regimen (docetaxel, doxorubicin, and cyclophosphamide). The study group was comprised of 2,072 women with operable or locally advanced breast cancer. They received two cycles of TAC and were then randomly assigned according to their clinical course. Patients with a complete or partial response were randomly assigned to receive four additional cycles of TAC followed by surgery (TACx6) or six additional cycles plus surgery (TACx8).
Patients who did not have a response of more than 50% reduction in tumor volume were considered nonresponders and were randomly assigned to TACx6 or to four cycles of vinorelbine and capecitabine (NX) before surgery. Dr. von Minckwitz presented data on the secondary objective of the trial, which was to determine disease-free survival and overall survival at five years and from an analysis of the treatment effects by breast cancer type.
A total of 1,025 patients received conventional therapy (TACx6), and 987 received response-guided therapy (TACx8 or TAC-NX). All the patients who received response-guided therapy fared better than those who received conventional treatment in both disease-free survival and overall survival.
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