Blood pressure medications may increase lip cancer risk
Long-term use of blood pressure medications that increase a person’s sensitivity to sunlight may raise the risk for lip cancer among non-Hispanic whites, who are considered the most susceptible group for the disease.
Photosensitizing drugs absorb energy from visible and/or ultraviolet light. The ensuing release of electrons generates reactive oxygen and free radicals that can damage certain components of skin and lip cells — including DNA — and produce an inflammatory response, according to researchers.
Gary Friedman, MD, an emeritus researcher at Kaiser Permanente Northern California Division of Research, and colleagues used prescription records and data about cancer occurrence to identify 712 patients diagnosed with lip cancer between Aug. 1, 1994, and Feb. 29, 2008. The researchers compared those patients with 22,904 controls who were matched for age and sex.
The researchers evaluated their use of the diuretic hydrochlorothiazide; hydrochlorothiazide combined with triamterene; nifedipine, a calcium channel blocker; lisinopril, an angiotensin-converting enzyme inhibitor; and atenolol, a nonphotosensizing beta adrenergic blocker.
The researchers controlled for smoking history, but they were not able to adjust for sun exposure — the most important risk factor for lip cancer — and lack of pigmentation in the lips.
Patients who received at least a 5-year supply of hydrochlorothiazide (OR=4.22; 95% CI, 2.82-6.31), hydrochlorothiazide combined with triamterene (OR=2.82; 95% CI, 1.74-4.55) and nifedipine (HR=2.50; 95% CI, 1.29-4.84) were at increased risk for lip cancer, the results showed. The risk appeared to increase with longer duration of use of those drugs, the researchers said.
The association was less clear with lisinopril (OR=1.42; 95% CI, 0.95-2.13). Atenolol, when used alone, was not associated with increased risk (OR=0.54; 95% CI, 0.07-4.08).
“Lip cancer remains rare, and an increased risk of developing it is generally outweighed by the benefits of these blood pressure drugs and other photosensitizing medications,” Friedman said in a press release. “Physicians prescribing photosynthesizing drugs should ascertain whether patients are at high risk of lip cancer by virtue of fair skin and long-term sun exposure, and discuss lip protection with them.”
Those protection strategies could include lip sunscreens and the use of a hat with a brim wide enough to shade the lips, the researchers wrote.
Disclosure: The study was funded by NCI.