Immunotherapy in Anal Cancer

Standard treatment for early-stage squamous cell cancer of the anal canal (SCCA) includes concurrent chemotherapy and radiation to achieve curative intent. Treatment options are limited, however, especially with locoregional disease relapse occurring in 20-30% of patients and about 10-30% of patients presenting with metastatic disease. With more than 90% of SCCAs occurring in the setting of HPV, immune-based therapies are now the target of possible new treatments for this rare disease. This review highlights the role of immunotherapy in HPV-associated SCCA.

Immunotherapy has been shown to extend progression-free survival and overall survival in various solid malignancies, including SCCA. So far, single-agent monotherapy with either nivolumab or pembrolizumab has shown durable clinical response with a tolerable side effect profile. The 2018 NCCN guidelines now advise nivolumab or pembrolizumab monotherapy as second-line treatment in the management of metastatic SCCA. Further investigation with immunotherapy continues to be critical for such a rare malignancy with few treatment options.