Hydroxychloroquine exposure does not affect skin cancer rates in solid organ transplant recipients

Summary: Abstract Body: Background: Solid-organ transplant recipients (SOTRs) are at increased risk of developing non-keratinocyte and keratinocyte skin cancers. Chloroquine and its derivative, hydroxychloroquine (HCQ) may play a role in decreasing cancer risk, including skin cancer, via disruption of autophagy (Rangwala et al. Autophagy 2014; Mehnert et al. Clin Cancer Res 2022). Objective: To determine whether HCQ exposure decreases skin cancer risk in SOTRs. Methods: We conducted a retrospective, matched case-control study using chart review data from a single, large academic center. Our patient population included all SOTRs who received a documented transplant before 2020. The population was subdivided by HCQ exposure, defined as HCQ therapy of ≥200mg daily for ≥1 year, and age-, sex-, and race-matched controls identified with 2:1 propensity score matching. We evaluated the development of biopsy-proven skin cancer in SOTRs with HCQ exposure (n=112), compared to HCQ-naïve matched controls (n=247). Results: In the HCQ-exposed cohort, 11.6% developed skin cancer after transplantation compared to 10.1% of HCQ-naïve matched controls. Median time to first skin cancer diagnosis post-transplant was 5.5 years in the HCQ-exposed cohort and 4.1 years in matched controls. Conclusions: Based on these preliminary findings, HCQ exposure does not mitigate the risk of post-transplant skin cancer development. However, further work must be done to better characterize the effect of HCQ exposure on post-transplant skin cancer development after controlling for sociodemographic factors and medical history, particularly autoimmune disease history and prior skin cancer history. Lily Guo¹, Kimberly Breglio², Elizabeth Fan¹, Jeana Chun¹, Melodi J. Whitley³ 1. Duke University School of Medicine, Durham, NC, United States. 2. Dermatology, University of Michigan Michigan Medicine, Ann Arbor, MI, United States. 3. Dermatology, Duke University School of Medicine, Durham, NC, United States. Clinical Research: Epidemiology and Observational Research