Oral contraceptives as risk factors for cervical adenocarcinomas and squamous cell carcinomas

To assess the hypothesis that oral contraceptives (OCs) increase the risk o f cervical adenocarcinomas, we conducted a six-center case-control study of 124 patients with adenocarcinomas, 139 with squamous cell carcinomas, and 307 population controls. Women between the ages of 18 and 69 who were newly diagnosed with cervical adenocarcinomas between 1992 and 1996 were eligibl e. Healthy female controls and a second case group of incident cervical squ amous cell carcinomas were matched to the adenocarcinoma cases, All partici pants were interviewed regarding OCs, other risk factors for cervical carci noma, and utilization of cytological screening, and a PCR-based test determ ined HPV genotype of cervical samples for both case groups and controls. Us e of OCs was positively and significantly associated with adenocarcinomas a nd positively but weakly associated with squamous cell carcinomas. Associat ions between OCs and invasive adenocarcinomas (n = 91), squamous cell carci noma in situ (n = 48), and invasive squamous cell carcinomas (n = 91) disap peared after accounting for HPV infection, sexual history, and cytological screening, but a positive association remained between current use of OCs a nd cervical adenocarcinoma in situ (n = 33), This association persisted aft er stratification by screening and sexual history and after restriction acc ording to HPV status, but small numbers made it difficult to exclude detect ion bias, selection bias, or residual confounding by HPV as potential expla nations. Current OC use was associated with cervical adenocarcinomas in sit u, but we saw no other evidence that OCs independently increase the risk of cervical carcinomas.