Hepatitis C coinfection and extrahepatic cancer incidence among people living with HIV

Objectives We assessed the incidence of extrahepatic cancer among people with HIV/HCV coinfection and the potential impact of direct-acting antivirals (DAAs) on extrahepatic cancer risk among people with HIV/HCV coinfection. Design Our study cohort included adults who initiated HIV care at a CNICS site in the US during 1995-2017, excluding those with previous cancer and without HCV testing. Methods We used Cox regression to estimate hazard ratios for extrahepatic cancer incidence among patients with HIV/HCV coinfection compared with those with HIV monoinfection. Standardized morbidity ratio (SMR) weights were used to create a 'pseudopopulation' in which all patients were treated with antiretroviral therapy (ART), and to compare extrahepatic cancer incidence among patients with untreated HIV/HCV coinfection with the incidence that would have been observed if they had been successfully treated for HCV. Results Of 18 422 adults, 1775 (10%) had HCV RNA and 10 899 (59%) were on ART at baseline. Incidence rates of any extrahepatic cancer among patients with HIV/HCV coinfection and HIV monoinfection were 1027 and 771 per 100 000 person-years, respectively. In SMR-weighted analyses, the risk of any extrahepatic cancer among patients with untreated HCV coinfection at baseline was similar to the risk if they had been successfully treated for HCV. Patients with untreated HCV coinfection at baseline had higher incidence of kidney, lung and inflammation-related cancers than if their HCV had been successfully treated, but these associations were not statistically significant. Conclusions We did not find evidence that treating HCV coinfection with DAAs would reduce the incidence of extrahepatic cancers among people with HIV receiving ART.