Despite its widespread use as a guideline-recommended, first-line agent for the treatment of hypertension, hydrochlorothiazide (HCTZ) may contribute to an increased risk of skin cancer, according to Armand B. Cognetta Jr., MD, and his associates in the division of dermatology, Mohs Micrographic Surgery Unit, Florida State University, Tallahassee.
The common, long-term use of HCTZ for treatment of hypertension, combined with its known photosensitizing effects, makes it a potential candidate for increasing the risk of squamous cell carcinoma (SCC) and other skin cancers.
To further elucidate the association between longterm HCTZ exposure and skin cancer risk, Dr. Cognetta and his associates screened medication lists of 75 patients seen in their Mohs practice over a period of 5 days for lifetime SCCs and HCTZ exposure. For this study, patients with more than 20 lifetime SCCs were considered high risk. They also conducted a literature review of previous studies exploring this relationship, from 1966 to 2015.
Of the 75 patients screened, 4 met the criteria for inclusion in the high risk category. These four patients had a combined lifetime total of 288 SCC and 98 basal cell carcinomas (BCCs), including 10 that were lip SCC. All four patients were non-Hispanic white males and had been taking HCTZ alone or in combination for 3-15 years (Dermatol Surg. 2016 Sep;42[9]:1107-9).
The literature search produced three relevant studies, all of which had large patient populations, published between 2008 and 2012, “demonstrating an increased risk of SCC or lip cancer” associated with HCTZ use, with the highest risk associated with over 5 years of use, the researchers wrote.
“As cutaneous oncologists, it is our duty to look for ‘correctable’ causes of skin cancer,” they noted. “Hydrochlorothiazide, a known photosensitizer, when taken by white non-Hispanic patients with a history of multiple SCC, skin cancers may represent a ‘correctable’ cause.”
In their practice, they screen their high-risk SCC non-Hispanic patients for HCTZ use, “and send a standard letter explaining the association to the primary care provider with a request to change to a different antihypertensive if possible,” they wrote. “Many primary care providers are unaware of the association between HCTZ use and skin cancer,” they observed.
The authors had no disclosures.