title: Hepatitis C virus infection and the risk of cancer among elderly US adults: A registry-based case-control study.
abstract: Hepatitis C virus (HCV) infection causes hepatocellular carcinoma (HCC) and subtypes of non-Hodgkin lymphoma (NHL). Associations with other cancers are not established. The authors systematically assessed associations between HCV infection and cancers in the US elderly population.
  
  
  
  This was a registry-based case-control study using Surveillance, Epidemiology, and End Results (SEER)-Medicare data in US adults aged ≥66 years. Cases (n = 1,623,538) were patients who had first cancers identified in SEER registries (1993-2011). Controls (n = 200,000) were randomly selected, cancer-free individuals who were frequency-matched to cases on age, sex, race, and calendar year. Associations with HCV (documented by Medicare claims) were determined using logistic regression.
  
  
  
  HCV prevalence was higher in cases than in controls (0.7% vs 0.5%). HCV was positively associated with cancers of the liver (adjusted odds ratio [aOR] = 31.5; 95% confidence interval [CI], 29.0-34.3), intrahepatic bile duct (aOR, 3.40; 95% CI, 2.52-4.58), extrahepatic bile duct (aOR, 1.90; 95% CI, 1.41-2.57), pancreas (aOR, 1.23; 95% CI, 1.09-1.40), and anus (aOR, 1.97; 95% CI, 1.42-2.73); nonmelanoma nonepithelial skin cancer (aOR, 1.53; 95% CI, 1.15-2.04); myelodysplastic syndrome (aOR, 1.56; 95% CI, 1.33-1.83); and diffuse large B-cell lymphoma (aOR, 1.57; 95% CI, 1.34-1.84). Specific skin cancers associated with HCV were Merkel cell carcinoma (aOR, 1.92; 95% CI, 1.30-2.85) and appendageal skin cancers (aOR, 2.02; 95% CI, 1.29-3.16). Inverse associations were observed with uterine cancer (aOR, 0.64; 95% CI, 0.51-0.80) and prostate cancer (aOR, 0.73; 95% CI, 0.66-0.82). Associations were maintained in sensitivity analyses conducted among individuals without documented alcohol abuse, cirrhosis, or hepatitis B or human immunodeficiency virus infections and after adjustment for socioeconomic status. Associations of HCV with other cancers were not observed.
  
  
  
  HCV is associated with increased risk of cancers other than HCC in the US elderly population, notably bile duct cancers and diffuse large B-cell lymphoma. These results support a possible etiologic role for HCV in an expanded group of cancers. Cancer 2017;123:1202-1211. © 2016 American Cancer Society.
authors.affiliation: Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, Maryland.|Department of Epidemiology, Human Genetics, and Environmental Sciences, The University of Texas School of Public Health, Houston, Texas.
authors.forename: Parag
authors.identifier: 0000-0003-1285-3310
authors.initials: P
authors.lastname: Mahale
authors.affiliation: Department of Infectious Diseases, Infection Control, and Employee Health, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Harrys A
authors.initials: HA
authors.lastname: Torres
authors.affiliation: Center for Innovations in Quality, Effectiveness, and Safety, Michael E. DeBakey Veterans Affairs Medical Center, Houston, Texas.
authors.forename: Jennifer R
authors.initials: JR
authors.lastname: Kramer
authors.affiliation: Department of Epidemiology, Human Genetics, and Environmental Sciences, The University of Texas School of Public Health, Houston, Texas.
authors.forename: Lu-Yu
authors.initials: LY
authors.lastname: Hwang
authors.affiliation: Department of Biostatistics, The University of Texas School of Public Health, Houston, Texas.
authors.forename: Ruosha
authors.initials: R
authors.lastname: Li
authors.affiliation: Department of Epidemiology, Human Genetics, and Environmental Sciences, The University of Texas School of Public Health, Houston, Texas.
authors.forename: Eric L
authors.initials: EL
authors.lastname: Brown
authors.affiliation: Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, Maryland.
authors.forename: Eric A
authors.initials: EA
authors.lastname: Engels
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D005260:Female; D016174:Hepacivirus; D006526:Hepatitis C / Q000150:complications* / Q000453:epidemiology / Q000821:virology; D006801:Humans; D008297:Male; D009369:Neoplasms / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology*; D016017:Odds Ratio; D015995:Prevalence; D012042:Registries; D012306:Risk; D018426:SEER Program; D012959:Socioeconomic Factors; D014481:United States / Q000453:epidemiology
keywords: Epidemiology; Surveillance; and End Results (SEER)-Medicare; cancers; cholangiocarcinoma; elderly; hepatitis C virus; hepatocellular carcinoma; lymphoma