While colorectal cancer may be the most common and deadly gastrointestinal malignancy, liver and gastric cancers account for some of the most consistent racial and ethnic disparities, a recent retrospective, cross-sectional analysis of U.S. data suggested.
Liver and gastric cancer incidence and mortality were significantly higher for all racial and ethnic minority groups in the study, compared with non-Hispanic Whites, according to the analysis. Notably, however, non-Hispanic Blacks represented the only group to also have elevated incidence and mortality for pancreatic and colorectal, compared with non-Hispanic Whites, according to investigator Aileen Bui, MD, with the University of California, Los Angeles Health.
These study results highlights the need to address modifiable cancer risk factors and overcome barriers to cancer prevention and care in medically underserved minority populations, Dr. Bui said in a virtual presentation of the results at the annual Digestive Disease Week® (DDW).
“While we cannot infer causation or determine risk factors for certain malignancies from the results of our study, there’s little data to support a strong role of biological or genetic differences between racial and ethnic groups to account for the observed disparities in incidence and mortality for GI cancers,” she said in her presentation.
Setting out to explore disparities
Gastrointestinal cancer incidence and mortality remain on the rise, despite significant progress in some areas, including colorectal cancer screening and the introduction of effective treatments for hepatitis C virus, Dr. Bui said.
Incidence and mortality from gastrointestinal cancers are set to increase by 34% and 43%, respectively, by the year 2040, and will remain a significant contributor to cancer incidence and mortality in the United States, according to the researcher.
Gastrointestinal cancer incidence and mortality are known to vary by race and ethnicity, so Dr. Bui and colleagues sought to assess the extent of racial and ethnic disparities for individual gastrointestinal cancer types. They identified more than 140,000 incident cases of colorectal, pancreatic, liver, esophageal, and gastric cancers in the Surveillance, Epidemiology, and End Results database from 2013 to 2017. They also incorporated nearly 185,000 mortality cases for those same types of malignancy from National Center for Health Statistics data from the years 2014 to 2018.
Breaking down the numbers
Overall, the incidence of colorectal cancer was highest, at 36.9 (cases per 100,000), followed by pancreatic cancer at 11.0, gastric cancer at 7.1, esophageal cancer at 4.1, and liver cancer at 3.0, Dr. Bui’s data show. The mortality rate was again highest for colorectal cancer, followed by pancreatic, liver, esophageal and gastric cancer.
When compared with non-Hispanic Whites, all racial ethnic minority groups had significantly higher incidence of both liver and gastric cancers, according to Dr. Bui.
The researchers calculated rate ratios for gastrointestinal cancer incidence and mortality, with ratios above 1 indicating a higher incidence relative to non-Hispanic Whites.
Among Hispanics, the incidence rate ratios were 1.83 for both liver and gastric cancers, according to the analysis. Similarly, non-Hispanic Asian Pacific Islanders had IRRs of 2.00 for liver cancer and 1.9 for gastric cancer. Non-Hispanic American Indians and Alaska Natives had IRRs of 2.09 for liver cancer and 1.51 for gastric cancer.
By contrast, non-Hispanic Blacks had significantly higher IRRs not only for liver and gastric cancers, at 1.64 and 1.8, respectively, but also for pancreatic cancer, at 1.18, and colorectal cancer at 1.17, Dr. Bui said.
Similar trends were seen in mortality in the presented data, with all racial and ethnic groups exhibiting significantly increased mortality RRs for liver and gastric cancer, compared with non-Hispanic Whites, but with non-Hispanic Blacks showing significantly increases in RRs for liver (1.66), gastric (2.36), pancreatic (1.22), and colorectal (1.36) cancers.
Esophageal cancer rates of incidence and mortality were both lower in racial and ethnic minority groups, compared with non-Hispanic whites, according to Dr. Bui.