(HealthDay News) — There has been a widening rural-urban disparity in changes in new cases of hepatocellular carcinoma (HCC) during the past two decades, according to a research letter published online Aug. 26 in Clinical Gastroenterology and Hepatology.
Kali Zhou, M.D., from the University of Southern California in Los Angeles, and colleagues assessed changes in HCC incidence by rural-urban residence using data from the North American Association of Central Cancer Registries. The analysis included incident cases diagnosed between 1995 and 2016 among adults older than 20 years of age.
The researchers identified 310,635 incident HCC cases, of which 85 percent were in urban areas and 15 percent in rural areas. The average age-adjusted incidence rates (AAIR) of HCC were lower in rural (4.85) versus urban areas (6.87) during the study period.
There was a higher average annual percentage change (AAPC) in incidence in rural (AAPC +5.70 percent) versus urban areas (AAPC +3.92 percent) between 1995 and 2016 despite the lower AAIR in rural areas, with the difference reaching statistical significance after 2009.
There has been a widening gap in percent change in AAIRs since 1995, with a 218 percent increase in AAIR for rural areas versus 118 percent for urban areas in 2016. In rural areas, men, non-Hispanic Blacks, American Indian/Alaskan Natives, and those aged 60 to 69 years, living in the South, or in areas with high census poverty (≥20 percent) had a continued rapid rise in incidence (annual percentage change ≥5 percent).
“We find that previously reported slowing of HCC incidence trends starting in 2009 mainly reflected trends in urban areas, given the dominant representation of urban residents in cancer databases,” the authors write.
One author disclosed financial ties to the pharmaceutical industry.