Survival of distinct Asian groups among colorectal cancer cases in California

Abstract

BACKGROUND It has been reported that Asian ethnicity confers a survival benefit in colorectal cancer (CRC) compared with other ethnicities, but it is not known if this is limited to specific Asian subsets. In the current study, the authors attempted to determine differences using data from the large, population-based California Cancer Registry (CCR). METHODS The authors conducted a case-only analysis of CCR data (1994–2003), including descriptive analysis of relevant clinical variables. Overall survival univariate analyses were conducted using the Kaplan-Meier method. Multivariate survival analyses were performed using Cox proportional hazards ratios (HR). RESULTS The 61,494 incident cases of colon and 24,350 incident cases of rectal cancer analyzed included 1905 Chinese, 1162 Filipino, 414 Vietnamese, 391 Korean, 1091 Japanese, 148 Asian Indian, and 77,554 Caucasians. After adjustment for age, sex, grade, histology, site within the colon, stage of disease, insurance status, socioeconomic status (SES), and therapy, Filipino (colon: HR, 0.85; 95% confidence interval [95% CI], 0.76–0.95) (rectum: HR, 0.82; 95% CI, 0.71–0.94) and Chinese ethnicity (colon: HR, 0.90; 95% CI, 0.92–0.98) had significantly decreased risk of death compared with Caucasians. Sigmoid lesions were independently associated with improved survival among all cases (HR, 0.92; 95% CI, 0.88–0.95) (referent group were proximal and transverse lesions), and among Asian-only cases in separate analysis (HR, 0.78; 95% CI, 0.70–0.87). CONCLUSIONS Although survival after CRC diagnosis is improved for Asians in general, significant survival differences are observed only in specific Asian subsets. Data from the current study suggest that survival among Asians is less affected by SES or treatment disparities, and may be because of biologic factors.

Comparative analysis of lifestyle factors, screening test use, and clinicopathologic features in association with survival among Asian Americans with colorectal cancer

“…That is, relative to other groups, Asians have higher rates of distal colon cancer, which is associated with a decreased risk of mortality. This further confirms the findings of previous studies (Le et al , 2009). We also found that Indian/Pakistani patients had better DSS than did other groups even after adjusted by age, tumour stage, grade, and tumour site.…”

Racial disparities in colorectal cancer survival

“…The persistent racial/ethnic survival differences, despite controlling for numerous variables, may be explained by differences in biology,33‐37 individual‐level SES,3 acculturation,38, 39 lifestyle,40 beliefs,41, 42 refusal of43, 44 and compliance with treatment,43, 44 post‐treatment surveillance,12, 13 and access to high‐quality cancer care,14 which were not investigated in the current study. Differences in tumor site distribution and genetics may explain the high survival rates observed among Asians.…”

“…Differences in tumor site distribution and genetics may explain the high survival rates observed among Asians. Relative to whites, Asians have higher rates of distal colon cancer, which is associated with a decreased risk of mortality 33. For blacks, poor survival may be caused by biologic features that contribute to aggressive tumor behavior7 or by inherited or acquired genetic abnormalities,35‐37 which may have an impact on response to therapy 37…”

Treatment at Academic Centers Decreases Insurance-Based Survival Disparities in Colon Cancer

“…Our findings are in agreement with several studies citing higher overall rates of survival in CC in Asians using state or county-level registries. 21,22 One of these studies also provided evidence that much of this survival benefit is due to genetic factors rather than socioeconomic factors. 21 Because our model accounts for socioeconomic c a b o e t a l h o s p i t a l t y p e a n d c o l o n c a n c e r d i s p a r i t i e s factors but not for genetic factors, there is the potential for inflation of perceived OS advantage in these patients.…”