Patients Taking Antihypertensive Drugs Show Increase in Lip Cancer

Cancer of the lip (i.e., of the vermillion border, commissure, and labial mucosa) is a rare malignancy (yearly incidence in the U.S., 0.7/100,000 persons). Usually occurring on the lower lip, this cancer is much less common in the dark-skinned, suggesting that sun exposure is a major causative factor. Prompted by epidemiologic studies that linked some antihypertensive medications with cutaneous squamous cell carcinomas (SCCs; presumably through photosensitization), investigators looked for an association with lip cancer as well.

They reviewed more than 13 years of pharmacy records from a large HMO and identified 712 cases of lip cancer among non-Hispanic whites who were not HIV-positive or organ transplant recipients at diagnosis. They compared these cases with 22,904 matched controls without lip cancer. The hypertension drugs hydrochlorothiazide (HCTZ), HCTZ-triamterene, and nifedipine were associated with a higher incidence of lip cancer; the relative risk for HCTZ users was 2.2 (odds ratio, 1.76–2.79). As expected, lip cancer was also associated with smoking, but the higher risk in HCTZ, HCTZ-triamterene, and nifedipine users remained after multivariable analysis. Lisinopril recipients had no increased lip cancer incidence, indicating that risk was drug related rather than hypertension related. The likelihood of developing lip cancer correlated positively with duration of treatment with these drugs. Those with at least 5 years of HCTZ treatment had a fourfold increase in lip cancer.