Impact of socioeconomic status on survival for patients with anal cancer

Although outcomes for patients with squamous cell carcinoma of the anus (SCCA) have improved, the gains in benefit may not be shared uniformly among patients of disparate socioeconomic status. In the current study, the authors investigated whether area-based median household income (MHI) is predictive of survival among patients with SCCA.

Patients diagnosed with SCCA from 2004 through 2013 in the Surveillance, Epidemiology, and End Results registry were included. Socioeconomic status was defined by census-tract MHI level and divided into quintiles. Multivariable Cox proportional hazards models and logistic regression were used to study predictors of survival and radiotherapy receipt.

A total of 9550 cases of SCCA were included. The median age of the patients was 58 years, 63% were female, 85% were white, and 38% were married. In multivariable analyses, patients living in areas with lower MHI were found to have worse overall survival and cancer-specific survival (CSS) compared with those in the highest income areas. Mortality hazard ratios for lowest to highest income were 1.32 (95% confidence interval [95% CI], 1.18-1.49), 1.31 (95% CI, 1.16-1.48), 1.19 (95% CI, 1.06-1.34), and 1.16 (95% CI, 1.03-1.30). The hazard ratios for CSS similarly ranged from 1.34 to 1.22 for lowest to highest income. Older age, black race, male sex, unmarried marital status, an earlier year of diagnosis, higher tumor grade, and later American Joint Committee on Cancer stage of disease also were associated with worse CSS. Income was not found to be associated with the odds of initiating radiotherapy in multivariable analysis (odds ratio of 0.87 for lowest to highest income level; 95% CI, 0.63-1.20).

MHI appears to independently predict CSS and overall survival in patients with SCCA. Black race was found to remain a predictor of SCCA survival despite controlling for income. Further study is needed to understand the mechanisms by which socioeconomic inequalities affect cancer care and outcomes. Cancer 2018;124:1791-7. © 2018 American Cancer Society.