Management of Metastatic Anal Cancer.

Metastatic squamous cell carcinoma of the anal canal is a rare presentation that is suspected in patients with risk factors such as known primary anal cancer, human papillomavirus/human immunodeficiency virus, immunosuppression, smoking, and receptive anal intercourse. Patients may present with metastasis at the index presentation of anal cancer or metastases may occur following the chemoradiation of the primary tumor. Treatment is focused on systemic therapy with chemotherapy, with the consideration of immunotherapy as second-line therapy. Predictive biomarkers may be able to personalize treatment in the future. Clinical trials of different chemotherapy and immunotherapy combinations are active to improve current management.