Colorectal cancer is the third leading cause of cancer mortality in the United States, with an expected 134 490 new cases and 49 190 deaths in 2016.¹ While incidence and mortality rates of colorectal cancer among adults aged 50 years and older have decreased in the United States in recent years,² the same trend has not been observed for patients aged 20 to 49 years. The decreased mortality among people aged 50 years or older may be related to the use of colorectal cancer screening recommended for individuals in this age group.^3-5 However, survival studies have shown inconsistent results. While some studies showed poorer survival for young patients as compared with their older counterparts,^6,7 others found better or comparable survival among younger patients.^8-13

Black women who receive a diagnosis of breast cancer have lower survival than their white counterparts in the general US population.^1-4 Documented racial differences in tumor characteristics and receipt of recommended treatments^3,5-7 may only partially explain survival disparities.^3,7 Time to first treatment has gained attention as a possible explanatory factor for survival disparities in nonmetastatic disease.^8-12 Treatment delays could lead to poorer treatment response, more rapid disease progression, or adverse health events^13,14 and may contribute to reduced overall survival.^8,12,15 Because surgery is the primary treatment for early-stage breast cancer,^16,17 time to surgery (TTS) may be important for racial disparities research.

Studies have shown that Whites have a higher colorectal cancer survival rate than Blacks. However, it is unclear whether racial disparities result from unequal access to medical care or factors other than health care access or both. This study assessed whether non-Hispanic Whites (NHW) and non-Hispanic Blacks (NHB) differ in colon cancer survival in an equal-access health care system and examined whether racial differences varied by demographic and tumor characteristics. The study included 2,537 Military Health System patients diagnosed with colon cancer between 1998 and 2007. Median follow-up time was 31.4 months. Cox models estimated HRs and 95% confidence intervals (CI) for race, overall and stratified by age at diagnosis, sex, and tumor stage. No difference in overall survival (OS) between NHWs and NHBs was observed in general. However, among patients younger than 50 years old, NHBs experienced significantly worse OS than NHWs (HR: 2.03, 95% CI: 1.30–3.19). Furthermore, stratification by sex and tumor stage showed that this racial disparity was confined to women (HR: 2.87; 95% CI: 1.35–6.11) and patients with distant stage disease (HR: 2.45; 95% CI: 1.15–5.22) in this age group. When medical care is equally available to NHWs and NHBs, similar overall colon cancer survival was observed; however, evidence of racial differences in survival was apparent for patients younger than 50 years old. This study suggests that factors other than access to care may be related to racial disparities in colon cancer survival among younger, but not older, patients. Cancer Epidemiol Biomarkers Prev; 22(6); 1030–6. ©2013 AACR.

Background: Although research suggests that type II diabetes mellitus (DM-2) is associated with overall and breast cancer–specific decreased survival, most prior studies of breast cancer survival investigated the effect of preexisting DM-2 without assessing the effect of DM-2 diagnosed at or after breast cancer diagnosis. This study examined the relationship between DM-2 diagnosed before and after breast cancer diagnosis and overall survival. Methods: This study uses linked Department of Defense cancer registry and medical claims data from 9,398 women diagnosed with breast cancer between 1998 and 2007. Cox proportional hazards models were used to assess the association between DM-2 and overall survival. Results: Our analyses showed that women with DM-2 diagnosed before breast cancer diagnosis tended to have a higher risk of mortality compared with women without diabetes [HR = 1.17; 95% confidence interval (CI), 0.95–1.44] after adjustment for potential confounders. Similarly, patients diagnosed with DM-2 at or after breast cancer diagnosis had increased mortality compared with women without DM-2 (HR = 1.39; 95% CI, 1.16–1.66). The similar tendency was also observed among most subgroups when results were stratified by race, menopausal status, obesity, tumor hormone receptor status, and stage. Conclusions: Using data from a health system that provides universal health care to its beneficiaries, this study showed an increased risk of death associated with DM-2, regardless of whether it was diagnosed before or at/after breast cancer diagnosis. Impact: These results suggest the potential effects of factors independent of the timing of DM-2 clinical diagnosis on the association of DM-2 with overall survival. Cancer Epidemiol Biomarkers Prev; 27(1); 50–57. ©2017 AACR.