Racial Disparity in Gastrointestinal Cancer Risk

Abstract

Cancer from the gastrointestinal tract and its associated excretory organs will occur in more than 300,000 Americans in 2017, with colorectal cancer responsible for >40% of that burden; there will be more than 150,000 deaths from this group of cancers in the same time period. Disparities among subgroups related to the incidence and mortality of these cancers exist. The epidemiology and risk factors associated with each cancer bear out differences for racial groups in the United States. Esophageal adenocarcinoma is more frequent in non-Hispanic whites, whereas esophageal squamous cell carcinoma with risk factors of tobacco and alcohol is more frequent among blacks. Liver cancer has been most frequent among Asian/Pacific Islanders, chiefly due to hepatitis B vertical transmission, but other racial groups show increasing rates due to hepatitis C and emergence of cirrhosis from non-alcoholic fatty liver disease. Gastric cancer incidence remains highest among Asian/Pacific Islanders likely due to gene-environment interaction. In addition to esophageal squamous cell carcinoma, cancers of the small bowel, pancreas, and colorectum show the highest rates among blacks, where the explanations for the disparity are not as obvious and are likely multifactorial, including socioeconomic and health care access, treatment, and prevention (vaccination and screening) differences, dietary and composition of the gut microbiome, as well as biologic and genetic influences. Cognizance of these disparities in gastrointestinal cancer risk, as well as approaches that apply precision medicine methods to populations with the increased risk, may reduce the observed disparities for digestive cancers.

Keywords: African American; Anal Cancer; Cancer Disparity; Cancer Epidemiology; Cancer Risk; Colorectal Cancer; Esophageal Cancer; Gastric Cancer; Hepatocellular Carcinoma; Pancreatic Cancer; Racial Disparity; Small Bowel Cancer.

Figure 1

Black:Non-Hispanic White (NHW) ratios for seven gastrointestinal track cancers, both genders, for 2014. Data derived from seer.cancer.gov. Note the higher incidence and mortality ratio for NHWs for esophageal cancer, and same incidence and mortality ratio for both Blacks and NHWs for anal cancer. All other cancers show higher incidence and mortality ratios for Blacks as compared to NHWs. In some cases, the mortality ratio is more excessive than the incidence ratio for Blacks, including that for stomach, colorectal, and small intestinal cancer.