Differences in Breast Cancer Stage at Diagnosis by Ethnicity, Insurance Status, and Family Income in Young Women in the USA

Abstract

Purpose: Describe the clinical and epidemiological data from young women with breast cancer and determine the association between ethnicity, insurance status, family income, and breast cancer stage at the diagnosis in this population.

Methods: Women under the age of 40 diagnosed with invasive breast cancer from 2010 to 2014 and identified in the Surveillance, Epidemiology, and End Results (SEER) 18 registries database were included. Binary logistic regression was applied in order to estimate the odds ratios (ORs) for factors that were potentially predictive for receiving a breast cancer diagnosis at stage I.

Results: Of 14,379 young women with invasive breast cancer, 70.9% of the patients were white, 15.9% black, and 13.2% classified as other ethnicity (American Indian, Asian, Pacific Islander). The initial clinical stage at diagnosis was stage I in 28.2%, II in 45.2%, III in 19.0%, and IV in 7.6%. The chi-square test showed a significant association between clinical stage at diagnosis and family income (p < 0.0001), insurance status (p < 0.0001), and ethnicity (p < 0.0001). The ORs for being diagnosed at stage I, regarding different factors, revealed that women with family income higher than US$ 85,000 were more likely to be diagnosed with stage I (OR [95%CI], 1.306 [1.173-1.454]; p value < 0.0001) when compared with patients with family income of less than US$ 60,000. Black women were less likely to be diagnosed with stage I (OR [95%CI], 0.676 [0.605-0.755]; p value < 0.0001), when compared with white women. Uninsured women were less likely to be diagnosed with stage I (OR [95%CI], 0.586 [0.529-0.648]; p value < 0.0001) when compared with women with insurance coverage.

Conclusion: Among young US women diagnosed with invasive breast cancer, most of them presented early stage disease. Women with black ethnicity, low income, and uninsured are at risk for late-stage presentation. Improvements in strategies to allow earlier breast cancer diagnosis in these at risk population are urged.

Keywords: Breast cancer staging; Ethnic disparities; Socioeconomic disparities.