A Population-Based Study of Squamous Cell Vaginal Cancer: HPV and Cofactors

Background. Little is known about the etiology of in situ or invasive squamous cell cancer of the vagina. It is thought that some vaginal cancers may have the same etiology as cervical cancer. It is also not known whether in situ and invasive vaginal cancer share the same etiologic factors. We conducted a study to evaluate risk factors for in situ and invasive vaginal cancer and their potential relationship to prior exposure to human papillomaviruses (HPV). Methods. A population-based case–control study included 156 women with squamous cell in situ or invasive vaginal cancer diagnosed between January 1981 and June 1998 and 2041 control women identified through random-digit dialing in western Washington state. Cases and controls were interviewed in person and provided blood samples; archival tumor tissue was retrieved for cases. Blood samples were tested for antibodies to HPV, and tumor tissue was tested for HPV DNA. Results. Women with vaginal cancer were more likely to have five or more lifetime sexual partners (OR = 3.1, 95% CI 1.9 to 4.9), to have an early age at first intercourse (