Mapping the potential for anti-PD-1 therapy in advanced rare skin carcinomas

Area of Science:

• Oncology
• Dermatology
• Immunotherapy

Background:

• Rare skin cancers, including adnexal carcinomas, extramammary Paget disease (EMPD), cutaneous angiosarcomas (cAS), and Kaposi sarcoma (KS), present unique challenges in treatment and management.
• Understanding tumor characteristics like tumor mutation burden (TMB) and PD-L1 expression is crucial for predicting treatment response.
• Systemic anti-PD-1 agents are increasingly explored for advanced or refractory cases of these rare skin malignancies.

Purpose of the Study:

• To review the efficacy of systemic anti-PD-1 agents in patients with advanced rare skin carcinomas.
• To summarize local recurrence, metastasis rates, tumor mutation burden (TMB), and PD-L1 expression in these tumor types.
• To evaluate treatment responses and identify potential predictive biomarkers for anti-PD-1 therapy.

Main Methods:

• A literature review was conducted to identify studies reporting on the use of systemic anti-PD-1 agents for adnexal carcinomas, EMPD, cAS, and KS.
• Data on patient demographics, tumor histology, TMB, PD-L1 expression, treatment regimens, and clinical outcomes (response rates, recurrence, metastasis) were extracted and analyzed.
• Case series and individual patient data were compiled to assess overall response rates and safety profiles.

Main Results:

• Responses to anti-PD-1 agents were observed across various rare skin carcinomas, including sebaceous carcinoma, porocarcinoma, spiradenocarcinoma, trichilemmal carcinoma, EMPD, cAS, and KS.
• Tumor mutation burden (TMB) and PD-L1 expression showed high variability and did not consistently correlate with treatment response; some patients responded despite low TMB or lack of PD-L1 expression.
• Encouraging overall responses were noted, particularly in patients with advanced disease who had failed prior systemic therapies, though treatment efficacy was limited by small patient numbers and varied therapeutic approaches.

Conclusions:

• Systemic anti-PD-1 agents demonstrate potential efficacy in treating advanced rare skin carcinomas, offering therapeutic options for patients with limited alternatives.
• Predictive biomarkers like TMB and PD-L1 expression are variable and require further investigation to fully understand their role in guiding anti-PD-1 therapy.
• Standardized clinical guidelines are needed to provide physicians with clear recommendations for the optimal use of anti-PD-1 agents in rare skin carcinomas, improving patient care and outcomes.