Cholangiocarcinoma Incidence Doubled in Publicly Funded Health Care System in Texas

The incidence of cholangiocarcinoma, a rare cancer with a high mortality rate, more than doubled in a largely underrepresented, minority population in Texas over 12 years.

In the United States, cholangiocarcinoma rates are rising, particularly among Hispanic and Asian individuals and younger age groups.

A retrospective cohort study, published earlier this year, was conducted from 2005 to 2017 among adults who received their care through the Houston-based Harris Health System, the publicly funded health care system for Harris County, Texas. Most patients belonged to racial minority groups (90%), with most patients (62%) being Hispanic, and more than half (54%) were uninsured. The cholangiocarcinoma cases were obtained through a prospectively maintained Harris Health System Cancer Registry.

Age-specific (the number of cases divided by person-years at risk in a specific age category) and age-adjusted incidence rates (the sum of expected cases in a standard US population across all age categories) per 100,000 were computed for 2 time periods, 2005 to 2011 and 2012 to 2017. Relative risk ratios were also assessed.

Researchers identified 139 cholangiocarcinoma cases (64% intrahepatic, 36% extrahepatic), with 40 patients in the first period and 99 in the second. The median age at diagnosis was 57 years, and most received their diagnosis when the disease was already at stage 4.

The incidence rate increased from 1.2 to 2.4 per 100,000 person-years (RR, 2.1; 95% CI, 1.5-3.0). Most of those who received a diagnosis in 2012 to 2017 were born outside the United States compared with those who got their diagnosis between 2005 and 2011 (67% vs 56%; P = .014).

Between time periods, Hispanic individuals (RR, 2.5; 95% CI, 1.6-4.0) and those aged 40 to 69 years (RR, 2.0; 95% CI, 1.2-3.0) had the highest rate of incidence increase.

Besides finding that Hispanic individuals and younger persons were more at risk, the study discovered that those with diabetes or who were overweight or obese also had a higher cholangiocarcinoma risk.

From 2012 to 2017, the risk of the disease among patients with diabetes was 1.4 times relative to those without (95% CI, 1.1-1.5) and 1.2 times among those who were overweight/obese relative to those who were not (95% CI, 1.1-1.6).

Although Hispanics have a higher prevalence of diabetes and are somewhat more obese or overweight nationally, the authors said it is uncertain to what degree these 2 factors play in developing cholangiocarcinoma. But they pointed out that the same strategies to reduce diabetes and obesity could reduce the risk of developing cancer.

The researchers said their findings were consistent with other studies, which have found worse outcomes for Hispanic patients with cholangiocarcinoma, higher mortality for Hispanic patients with intrahepatic cholangiocarcinoma, worse outcomes for those in lower socioeconomic circumstances, and delayed chemotherapy and surgery for uninsured Hispanic patients with the disease.

“Our findings add to nationwide data that demonstrate increased incidence among Hispanic and younger populations, causing concern for widening health disparities,” they wrote.

The authors pointed out that in their Texas cohort, the median age at diagnosis was 57 years compared with 67 years for intrahepatic cholangiocarcinoma and 72 years for extrahepatic cholangiocarcinoma cases nationally.

Their work is important to understand national trends, the researchers said.

One limitation to the study is that they were not able to perform multivariable logistic regression to identify risk factors and confounders of the disease or to say what effect the included comorbidities had on disease development.

“Further investigation should be directed at understanding the epidemiology and risk factors of this high-mortality cancer to mitigate health disparities among high-risk populations, such as individuals who are Hispanic and those with diabetes mellitus or obesity," the researchers concluded.

Reference

Kumar D, Bansal V, Raza SA, Thrift AP, Malaty HM, Sealock RJ. Widening health disparities: increasing cholangiocarcinoma incidence in an underserved population. Gastro Hep Adv. 2022;1(2):180-185. doi:10.1016/j.gastha.2021.12.003