Matched-pair analysis of female and male breast cancer: a comprehensive cohort study.

Abstract

Abstract Abstract #4129 Introduction:
 Male breast cancer (MBC) is a rare disease accounting for approximately 1% of all breast carcinomas. Due to the low incidence treatment guidelines based on prospective studies are lacking. Presently treatment recommendations are derived from the standards for female breast cancer. However, those approaches might be inadequate because of distinct gender specific differences in tumor biology of breast cancer. This study was planned in order to elucidate potential differences between female and male breast cancer in both tumor biological behavior and clinical practice.
 Patients and Methods:
 MBC diagnosed 1995-2007 (region Chemnitz/Zwickau, Saxony, Germany) was retrospectively analyzed. Tumor characteristics, treatment and follow-up of the patients were documented. In order to highlight potential differences matched-pairs of female and male breast cancer patients were created. Each MBC was matched with a female counterpart (FBC) that showed accordance in at least 5-7 tumor characteristics (age, TNM, grade, hormone receptors, HER2 stage).
 Results:
 FBC and MBC (n=113 patients each) were evaluable for this analysis. For MBC the following tumor characteristics were documented: >60% advanced stages (T2-4), only 6% well differentiated, 42.5% nodal-positive, 86% hormone-sensitive (ER-positive 79.2%, PR-positive 76.9%), 6.2% HER2 positive.
 83.2% of MBC had a mastectomy/axillary dissection (FBC 49.0%), 55% adjuvant radiotherapy (FBC 66.7%), 64% adjuvant systemic therapy (FBC 80.6%), 32.7% chemotherapy (FBC 49.5%) and 47.8% endocrine treatment (FBC 60.1%). 31% of MBC had a relapse (FBC 25.9%), 68.1% overall survival (OS) (FBC 70.4%), 98 months (FBC 76 months) median survival time. In univariate analyses reduced OS of MBC was significant associated with advanced tumor stages (p<.005), poor histological grade (p<.05), receptor negative (p<.05) and nodal-positive tumors (p<.05). Furthermore adjuvant radiotherapy showed survival benefit. However, in multivariate analysis only tumor stage showed statistical significance (p<.01). Regarding these tumor characteristics no OS differences could be observed between FBC and MBC. However, MBC showed a trend to a shortened survival for receptor negative tumors in comparison to FBC (p=.055).
 Discussion:
 1. Delayed diagnosis of MBC; 2. Our study showed more advanced and undifferentiated tumors with a high percentage of nodal positivity; 3. In our analysis these unfavorable tumor characteristics were not related to a poor OS; 4. We found no significant differences regarding disease outcome between FBC and MBC; despite of a more aggressive adjuvant treatment for FBC. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 4129.