Abstract A85: Age-specific racial disparity of survival between African Americans and whites in breast cancer for postsurgery patients: A retrospective study from a community hospital in New York City
Authors: Wang Hua , Singh Awinder P. , Surani Aleem , Villani Gina M. , St. Luce Serena , Cai Dongsheng , Go Alan R. , Pappas Peter J. 
Published: June 2012

Background: Breast cancer survival has significantly improved during the past two decades. Several reports have suggested a difference in outcomes for African American (AA) women. Specifically, AA women appear to have a higher mortality rate despite a lower incidence of the disease. Although a number of risk factors have been implicated as explanations for this disparity, the exact cause is still unknown. The aim of this study is to investigate the post-surgery survival rate between AA and White women in a community hospital setting.

Methods: This is a retrospective analysis of prospectively collected data from The Brooklyn Hospital Center's cancer registry from 1997 to 2010. Of the 1538 patients in the registry, 201 were excluded leaving 1337. Among the 1337 patients, 1055 are AA, 235 are white, and 57 are Asian (not included in the data analysis). Statistical analyses were done by SPSS and Epi info software. Kaplan–Meier survival probabilities are calculated and multivariate Cox proportional hazards models were applied to estimate hazard ratios (HR) with 95% confidence intervals.

Results: The average age at diagnosis is 61.43 (SD±14.81) in AA women and 60.33 (SD±14.66) in White women (p=0.607). There were no significant differences in distribution of tumor location and pathologic TNM stage between the two ethnic groups. No difference in the percentage of patients who received chemotherapy was identified between these two groups. Modified radical mastectomy (MRM) and lumpectomy are most two common procedures performed with no difference of the distribution in these two groups either. The appreciable marginal difference was high histological grade in AA compared with White with p=0.043, ER status 333/512 (65% positive) in AA and 65/85 (76.5% positive) in White (p=0.046), and PR status 287/512 (56% positive) in AA and 57/85 (67.1% positive) in White (p=0.059). Kaplan Meier survival analysis showed no significant difference between these two ethnic groups. However, when age was divided into three subgroups, &lt;45 years, 45–60 years, and &gt;60 years a significant difference presented in the subgroup aged 45–60 years (Log-rank p=0.05). 5 year survival probability in AA is 86.98% and in White is 92%. Cox Hazard ratio 1.90, 97.61% confidence, interval 3.72, pathological stages and the number of lymph nodes removed were associated with the prognosis (p=0.052). However, there is no difference of the distribution in terms of the tumor grade, pathological stages and ER/PR status between AA and White in this age subgroup.

This retrospective study has compared post-surgery survival in two ethnic groups in a community based setting. Our data indicates that AA women present with a higher histologic grade tumor and a lower ER/PR status compared to white women. Although there was no difference in overall survival between the two groups, we noted a higher mortality rate in AA women between the ages of 45–60 years of age. This difference may be related to post-menopausal physiologic changes or genetic causes like HER-2 neu status that were not investigated in this study. In the future, registries should collect genetic data to further elucidate possible mechanisms associated with racial mortality differences.

Citation Information: Cancer Epidemiol Biomarkers Prev 2011;20(10 Suppl):A85.