Understanding gastrointestinal cancer mortality disparities in a racially and geographically diverse population

BACKGROUND

Gastrointestinal (GI) cancers represent a diverse group of diseases. We assessed differences in geographic and racial disparities in cancer-specific mortality across subtypes, overall and by patient characteristics, in a geographically and racially diverse US population.

METHODS

Clinical, sociodemographic, and treatment characteristics for patients diagnosed during 2009-2014 with colorectal cancer (CRC), pancreatic cancer, hepatocellular carcinoma (HCC), or gastric cancer in Georgia were obtained from the Surveillance, Epidemiology, and End Results Program database. Patients were classified by geography (rural or urban county) and race and followed for cancer-specific death. Multivariable Cox proportional hazards models were used to calculate stratified hazard ratios (HR) and 95% confidence intervals (CIs) for associations between geography or race and cancer-specific mortality.

RESULTS

Overall, 77% of the study population resided in urban counties and 33% were non-Hispanic Black (NHB). For all subtypes, NHB patients were more likely to reside in urban counties than non-Hispanic White patients. Residing in a rural county was associated with an overall increased hazard of cancer-specific mortality for HCC (HR = 1.15, 95% CI = 1.02-1.31), pancreatic (HR = 1.11, 95% CI = 1.03-1.19), and gastric cancer (HR = 1.17, 95% CI = 1.03-1.32) but near-null for CRC. Overall racial disparities were observed for CRC (HR = 1.18, 95% CI = 1.11-1.25) and HCC (HR = 1.12, 95% CI = 1.01-1.24). Geographic disparities were most pronounced among HCC patients receiving surgery. Racial disparities were pronounced among CRC patients receiving any treatment.

CONCLUSION

Geographic disparities were observed for the rarer GI cancer subtypes, and racial disparities were pronounced for CRC. Treatment factors appear to largely drive both disparities.

Long-term exposure to ambient fine particles and gastrointestinal cancer mortality in Taiwan: A cohort study

BACKGROUND

Information on the association between long-term exposure to PM_2.5 and gastrointestinal cancer mortality is scarce.

OBJECTIVES

This study investigated the association between long-term exposure to PM_2.5 and deaths from gastrointestinal cancer and its subtypes in adults in Taiwan.

METHODS

A total of 385,650 Taiwanese adults (≥18 years old) jointed a standard medical examination program between 2001 and 2014 and were followed up until 2016. Their vital data were obtained from the National Death Registry maintained by the Ministry of Health and Welfare in Taiwan. We estimated the ambient PM_2.5 concentration at individual's address utilising a satellite-based spatiotemporal model at a resolution of 1 km². Cox proportional hazard regression model was used to investigate the associations between ambient PM_2.5 and deaths from gastrointestinal, stomach, colorectal and liver cancers.

RESULTS

We found that each 10 µg/m³ increase in PM_2.5 was associated with an increased hazard risk (HR) of 1.09 (95% confidence interval (CI): 1.03-1.16) and 1.13 (95%CI: 1.02-1.24) in deaths from gastrointestinal and liver cancers, respectively. The association between PM_2.5 and death from colorectal cancer was marginally statistically significant [HR: 1.13 (95%CI: 1.00-1.26)]. We did not find significant associations between PM_2.5 and mortality from stomach cancer.

CONCLUSIONS

Long-term exposure to ambient PM_2.5 was associated with an increased risk of deaths from gastrointestinal cancers, liver cancer and also potentially colorectal cancer. Air pollution control strategies are necessary to reduce the burden of gastrointestinal cancer.