Abstract P6-15-01: A comparative analysis of primary tumor resection in men and women with stage IV breast cancer

Abstract

Abstract Background: Primary tumor resection (PTR) for metastatic female breast cancer continues to be debated. Given the rarity of male breast cancer, treatment paradigms for female breast cancer are extended to the management of male breast cancer. Whether the role of PTR in men with metastatic breast cancer is similar to that in women remains unclear. We sought to compare these two populations using a large, national database. Methods: All patients with Stage IV breast cancer between the years 1988-2011 in the SEER database were identified. Uni and multivariate descriptive and survival analyses were performed. Results: A total of 41,601 patients with stage IV breast cancer were identified; 98.9% (n=41,162) females, 1.1% (n=439) males. On average, female patients were younger (63 vs. 66y) and more often White (78 vs. 74%), p≤0.02. Tumors in male patients were more likely to be hormonally positive, with varying breakdown of T and N-stages and histologic subtypes as compared to tumors in females, p≤0.05. Males were more likely to undergo PTR (51 vs.40%, p<0.05), however both males and females had similar rates of radiotherapy (35 vs. 32%, p=0.35). Among male patients, those who received PTR were of similar age to those who did not receive PTR (p=0.64), but had a greater representation of White patients (p=0.04). There were differences in T-stage, N-stage and hormonal status between men who did and did not receive PTR, p≤0.05. Men receiving surgery were also more likely to receive radiation therapy (38 vs. 32%, p=0.003). In women, all demographic and tumor-related factors were significantly different between those who did and did not undergo PTR. On univariate analysis, surgery was associated with improved disease-specific median survival in both men (36 vs. 21 mths) and women (34 vs. 18 mths), p<0.05. Younger age, White race, lower T and N-stage, lower grade, hormonal positivity, mucinous histology, and radiation therapy were associated with improved disease specific survival (DSS) in females, while only lower T-stage, hormone positivity and mucinous histology were associated with improved DSS in men. On multivariate analysis, a lack of resection of the primary tumor remained independently associated with increased mortality in men (HR 1.91, p<0.05) and women (HR 1.6, p<0.05). Over the study period there was a decrease in the rate of surgery in both men and women, p≤0.0006, but only women were found to have a statistically significant improvement in DSS with surgery over time. Conclusion: Regardless of gender, patients with metastatic breast cancer who underwent primary tumor resection had a significant improvement in DSS. Factors associated with DSS varied between male and female patients, but the reasons for this difference are unclear. A well designed randomized trial including both genders will help determine the utility of PTR in stage IV breast cancer patients. Characteristics of Stage IV Breast Cancer in Males: Surgery vs. No surgery (S = ≤ p.05) Surgery (%)No surgery (%)P-valueWhite race78.468.7ST1 stage15.87.4SN1 stage27.538.6SER +72.557.6SPR +57.245.2SHer2 +1.43.70.25Grade II34.726.3SInfiltrating ductal carcinoma76.656.2SRadiation therapy37.832.3SYear of diagnosis 1988-19928.17.4S2008-201125.236.9S Citation Format: Nasreen A Vohra, Swapnil D Kachare, Timothy L Fitzgerald, Jan H Wong, Mahvish Muzaffar. A comparative analysis of primary tumor resection in men and women with stage IV breast cancer [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P6-15-01.