Advancing Education, Research, and Quality of Care for the Head and Neck oncology patient.
Background: Hydrochlorothiazide (HCTZ), one of the most widely prescribed diuretics and antihypertensive medications, has been linked to photosensitivity and a dose-dependent, increased risk of both melanoma and non-melanoma skin cancer. Currently, the association between HCTZ use after cancer diagnosis and survival in melanoma remains unclear. This study examines risk and survival differences in melanoma patients who are on HCTZ compared to those who are not.
Methods: This is a retrospective cohort study utilizing the SEER-Medicare data resource. Patients above age 65 who were diagnosed with melanoma between 2011-2015 were included in our study. Prescriptions of HCTZ at least 60 days in length in the year following cancer diagnoses were included. Given demographic and tumor differences, propensity score matching was performed based on age, race/ethnicity, sex, T/N/M stage, treatment modality, and housing context. Multivariable Cox Proportional Hazards analysis was performed, and the variables included in the final model were selected using backwards stepwise regression. Patients with survival less than one year were excluded to address immortal time bias.
Results: A total of 21426 patients met our inclusion criteria. Of these, 2397 received HCTZ in the year after diagnosis. Propensity score matching was performed to match these patients to 2397 non-HCTZ patients. 2-year overall survival (OS) in the HCTZ cohort was 0.975 compared to 0.960 in the matched no-HCTZ cohort and 5-year OS was 0.880 vs. 0.830, respectively (p<0.001). There was no significant difference in cancer-specific survival (CSS) between the two cohorts, 2-year CSS was 0.990 vs. 0.989 and 5-year CSS was 0.965 vs. 0.966 (p=0.71). When comparing risk of OS and CSS between the two cohorts, Multivariable Cox Proportional Hazards analysis revealed a hazard ratio (HR) for all-cause death of 0.629 for patients on HCTZ when compared to patients not on HCTZ (p<0.001); the HR for cancer-specific death was 0.753 and this was not statistically significant (p=0.080)
Conclusion: This study provides preliminary evidence suggesting a benefit in overall survival but not cancer-specific survival in patients with melanoma taking HCTZ. This potentially suggests that the use of HCTZ does not predict a worse disease course, even though it may be associated with photosensitivity and an increased risk of melanoma development. It also suggests a benefit of HCTZ not directly tied to melanoma progression. HCTZ usage in melanoma patients merit further investigation to improve medication management and health outcomes.