Hydrochlorothiazide use ups risk for Merkel cell carcinoma, malignant adnexal skin tumours
Use of hydrochlorothiazide appears to increase the risk for Merkel cell carcinoma (MCC) and malignant adnexal skin tumours (MAST), a recent study has found.
High use (≥50,000 mg) of hydrochlorothiazide was associated with risk of MCC (adjusted odds ratio [OR], 2.3; 95 percent CI, 1.1–4.8) and MAST (adjusted OR, 3.6; 1.9–7.0). The adjusted ORs increased to 3.3 (1.3–8.3) and 5.6 (2.4–13.3), respectively, with highest use (≥100,000 mg).
There was no risk increase for these tumours in analyses of drugs with similar indications as hydrochlorothiazide. However, a tendency was observed toward a heightened risk for MCC associated with the use of furosemide (OR, 1.9; 0.9–4.0).
In earlier studies, findings showed that hydrochlorothiazide use was associated with a substantially increased risk of nonmelanoma skin cancer, especially squamous cell carcinoma (SCC), as well as lip cancer. [J Am Acad Dermatol 2018;78:673-681.e9; J Intern Med 2017;282:322-331]
The present study used Danish nationwide health registries to identify all patients with incident MCC or MAST during 2004–2015. Patients were matched individually to cancer-free population controls by risk set sampling. Conditional logistic regression was used to estimate the ORs and CIs associated with cumulative use of hydrochlorothiazide.
The study was limited by the absence of data on sun exposure.
“Hydrochlorothiazide use has been associated with markedly increased risk for SCC,” the authors noted. “No previous studies have investigated the association between hydrochlorothiazide use and the risk for MCC and MAST.”