Study finds rates of most common form of liver cancer rising in rural areas while slowing in urban areas
Newswise – LOS ANGELES – Hepatocellular carcinoma (HCC) is the most common form of liver cancer and the fastest growing cause of cancer-related death in the United States, according to National Cancer Statistics.
Historically, HCC rates are lower in rural areas than in urban areas. However, a new study from the USC Norris Comprehensive Cancer Center, part of Keck Medicine of USC, shows that while cases of HCC have started to slow in urban communities, cancer incidence is increasing at a rate of 5. , 7% per year in rural areas and approaching the rates observed in urban areas.
“Considering that one in five Americans live in a rural community, this study suggests that HCC is a critical and unrecognized public health problem affecting rural Americans,” said Kali Zhou, MD, MAS, gastroenterologist and hepatologist with Keck Medicine and co-lead author of the study. She is also an associate member of USC Norris and an assistant professor of clinical medicine at the Keck School of Medicine at USC.
Rural subgroups experiencing rapid increases in HCC included males aged 60 to 69, non-Hispanic blacks, American Indian / Alaskan natives, and those living in the south of the country or in an area. very poor area.
The researchers also found that some urban subgroups experienced a drop in HCC incidence rates from 2013, including males and females, youth aged 40 to 59, South Asian Islanders. Pacific and people living in the western United States. No rural subgroup experienced a significant decline during the study period, which is between 1995 and 2016.
Previous research indicates that this upward trend among rural communities is not evident with other common cancers, the study notes. The rate at which rural residents develop lung, breast and colorectal cancers is declining.
Zhou and colleagues examined trends in HCC in rural and urban communities over the past 20 years for which data is available using the North American Association of Central Cancer Registries database, which covers 93% of the United States and well represents the rural areas of the country. They looked at cases diagnosed between 1995 and 2016 in adults over the age of 20.
Of the more than 310,000 new cases of HCC, 85% were diagnosed in urban areas and 15% in rural areas. The researchers tracked new cases per year for both geographic groups and found that, although over all 20 years, the average rate of new cases was still lower in rural areas compared to urban areas, the cases grew at a higher average percentage rate per year in rural areas. areas.
The rates of increase were similar for the two groups from 1995 to 2009. However, in 2009, the rate of new HCC cases in urban America began to slow, peaking around 2014, with no corresponding slowdown in the rate. Rural America. In 2016, this meant that the number of cases had increased by 218% compared to 1995 in rural areas, compared to 118% in urban areas.
While the study did not examine why rural America’s annual change in new HCC cases exceeds that in urban communities, the researchers believe there may be several factors at play. “L âObesity and alcohol consumption, two risk factors for liver cancer, may be more prevalent in rural populations,â Zhou said.
Residents of rural areas also may not have the same access to health care as city dwellers, she added, resulting in a lack of preventive cancer care.
Zhou’s previous research has shown that people living in rural parts of the country are also more likely to be diagnosed with advanced liver cancer and have worse survival rates than those in urban communities.
She hopes this study will encourage further research into the health care needs of rural populations, as well as investment in more medical resources.
âWith the growing disparity between rural and urban areas in the incidence of HCC, such interventions are essential to better understand and address this growing inequality,â Zhou said.
Christina Gainey, MD, medical resident of the LAC + USC Medical Center Pediatric Residency Program, which is jointly sponsored by the Keck School and LAC + USC Medical Center, is a co-author of the study. Other researchers include Jennifer Dodge, MPH, assistant professor of research in medicine and in population and public health sciences at the Keck School; Wendy Setiawan, PhD, Professor of Population and Public Health Sciences at Keck School and Co-Head of the Cancer Epidemiology Program at USC Norris; Lihua Liu, PhD, associate professor of clinical population and public health sciences at Keck School; Myles Cockburn, PhD, professor of population and public health sciences at the Keck School; and Norah Terrault, MD, Keck Medicine gastroenterologist and division chief of gastroenterology and liver disease at the Keck School.
The study was funded by the USC Research Center for Liver Disease.
For more information on USC’s Keck Medicine, please visit news.KeckMedicine.org.