Abstract P3-14-10: Conversion to node-negative after neoadjuvant chemotherapy is a surrogate prognostic marker in patients with hormone receptor-positive breast cancer

Abstract

Abstract Background: While pathologic complete response (pCR) after neoadjuvant chemotherapy (NAC) improves patients’ survival with HER2-positive and triple-negative (TN) breast cancers, it has been reported not to be the same for patients with hormone receptor (HR)-positive breast cancer. However, it is not well known whether chemosensitivity presented by change in tumor stage or nodal status after NAC contributes to improve the prognosis with HR-positive breast cancer. The aim of this study was to evaluate the impact of change in tumor stage or nodal status after NAC on prognosis in patients with primary breast cancer. Patients and Methods: We assessed retrospectively 599 consecutive patients with primary breast cancer (a median age of 49 years, ranging 26-79 years) who underwent surgical resection after NAC between 2001 and 2008. HR (ER and PR) statuses were determined by immunohistochemistory (IHC). HER2 status was determined by IHC and/or fluorescent in situ hybridization assays. ER-positive and PR-positive patients were 426 (71.1%) and 353 patients (58.9%), respectively. HER2 status was positive in 130 patients (21.7%). HR-positive subtype was defined as ER and/or PR-positive and HER2 negative. We compared the patients with respect to disease-free survival (DFS) and overall survival (OS) based on change in tumor stage and nodal status after NAC. pCR was defined as no residual invasive tumor and ypN0. Results: After NAC, 84 (14.0%) patients had pCR. Two hundred ninety one (48.6%) decreased tumor stage and 308 (51.4%) did not decrease tumor stage. Regarding nodal status, 190 (31.7%) had cN0 and 409 (68.3%) had cN+ before NAC, and 286 had ypN0 (47.7%) and 313 had ypN+ (52.2%). For patients with TN breast cancer, patients with pCR had excellent prognosis compared to those with residual tumor in either the breast or lymph node (non-pCR) (DFS, p<0.01, and OS, p = 0.035, respectively). Among the non-pCR group, patients with ypN0 also have longer DFS and OS than patients with ypN+ (p<0.01, and p = 0.031, respectively). However, for ypN0 patients with TN breast cancer, patients with residual primary tumor had significantly shorter DFS and OS than patients with ypT0. For HR-positive breast cancer patients, there was a trend that patients with pCR had better DFS than patients with non-pCR (p = 0.069). In terms of OS, there was no significant difference between pCR and non-pCR (p = 0.285). Patients with ypN0 had significantly longer DFS and OS than those with ypN+ regardless of residual tumor stage (p< 0.001 and p = 0.01, respectively). Change in tumor stage itself did not contribute to improve patients’ survival. Conclusions: Our results revealed that HR-positive breast cancer patients with conversion to lymph nodes metastasis after NAC have a good prognosis even if they have residual tumor in the breast, while TN breast cancer patients require pCR to have a good prognosis. It indicated that conversion to node-negative after neoadjuvant chemotherapy might be a surrogate prognostic marker in patients with HR-positive breast cancer. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P3-14-10.