Systematic review on outcomes of the use of adjuvant pharmacotherapy for treatment of cutaneous malignancies exhibiting perineural invasion: promising efficacy of anti-PD1 therapy.

There is a paucity of the literature regarding the utility of pharmacotherapy in the management of cutaneous malignancies exhibiting perineural invasion (PNI). We aimed to systematically review the literature to provide an overview of the effectiveness of pharmacotherapy in treating cases of skin cancers with PNI in which first line therapy (MMS ± radiotherapy) is insufficient or contraindicated. A systematic review of PubMed and Wiley Online Library, from 1990 to July 14, 2022, identified all cases of cutaneous malignancies with PNI treated with pharmacotherapy with or without prior surgery/ radiotherapy. A total of 121 patients were included over 17 studies. The mean patient age was 72 (range, 26-94). The most commonly treated cutaneous malignancy was squamous cell carcinoma (n = 92). The most utilized chemotherapy was cisplatin (n = 46). However, anti-PD1 therapy had the best overall result with 61% of patients having complete local response (CLR) or stable disease. Three articles did not report specific patient outcomes, and all studies were either case reports or retrospective chart reviews. Our review shows the efficacy of anti-PD1 therapy particularly in conjunction with surgery and RT. Although chemotherapy does have beneficial outcomes based on anecdotal evidence in select cases, more powerful research in the form of randomized clinical trials is imperative to obtain a more comprehensive understanding of its utility.