Systemic strategies for chemoprevention of skin cancers in transplant recipients

Background: Solid organ transplant recipients (OTRs) are a growing population at high risk for cutaneous neoplasms, resulting in significant post-transplant morbidity and mortality. Management of malignant and pre-malignant cutaneous lesions in transplant recipients is challenging, making prevention of such neoplasms paramount. The objectives of the present study are to review and analyze systemic strategies for chemoprevention of malignant and pre-malignant cutaneous neoplasms in OTRs. Methods: MEDLINE and PubMed searches were performed to identify studies with original data quantifying the effects of systemic agents on the development of malignant cutaneous neoplasms in patients with solid organ transplants. Results: We identified nine studies describing 111 transplant recipients that quantified the effects of oral retinoids on cutaneous neoplasms. A majority of the studies found a decrease in the number of malignant and pre-malignant cutaneous lesions in patients treated with systemic retinoids, with several studies noting increased benefit in those patients with multiple previous skin cancers. Multiple studies described a rebound effect, with increased numbers of neoplasms occurring following discontinuation of retinoids. Side effects often limited dosing, but required discontinuation of retinoids in a minority of patients. No studies were identified that adequately quantified the effects of other systemic agents on skin cancer incidence in this population. Conclusions: Although systemic retinoids are frequently used for chemoprevention of cutaneous malignancies in OTRs, the data supporting their use are composed largely of small uncontrolled case reports and case series. However, the available data suggest that retinoids have chemopreventative effects in this population. Although optimal dosing and indications for initiation of systemic retinoid therapy are not conclusive from the data, it suggests that retinoids are most effective in patients with multiple previous non-melanoma skin cancers. Side effects and beneficial effects were noted across a wide range of doses, suggesting that retinoids should be initiated at a low dose and increased as tolerated to a minimally effective dose. Further investigation through randomized controlled trials is needed to further clarify the tolerability and efficacy of multiple dosing regimens on the incidence of pre-malignant and malignant lesions in transplant recipients. The therapeutic role of other systemic agents in the transplant population has not been established.