Background: Anal cancer is a rare cancer with chemoradiation being the mainstay of treatment for locoregional presentation. In North America, the most common subtype is anal squamous cell carcinoma (epidermoid). A surgical approach is considered for persistent or recurrent anal disease and systemic chemotherapy for metastatic disease. We are presenting a unique case of recurrent anal cancer with isolated peritoneal malignancy, an oligometastatic state which is rare in itself. It was treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy. There are currently no clear guidelines for the aforementioned presentation. The discussion drew on the feasibility and safety of this approach.
Case presentation: A 68-year-old woman diagnosed with an epidermoid anal cancer (stage 3B) was initially treated with chemoradiation therapy (Standard Nigro Protocol) in 2014. At the 5-year mark post-treatment, she was diagnosed with a recurrent anal epidermoid cancer in the form of isolated peritoneal carcinomatosis proven by biopsy. After declining systemic chemotherapy, she underwent cytoreductive surgery and hyperthermic intraperitoneal chemotherapy with Mitomycin-C©. Peritoneal carcinomatosis index was evaluated at 10, and intraoperative frozen sections were positive for carcinoma of epidermoid origin compatible with anal cancer. A completeness of cytoreduction score of 0 was achieved during the cytoreductive surgery, and her hospital course was unremarkable. She remains disease-free 12 months later.
Conclusions: To our knowledge, this is the first case reporting the disease presentation of anal cancer with oligometastatic dissemination to the peritoneum. Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy were performed. Thus far, this approach seems to be a safe and feasible option for short-term control of the disease.
Keywords: Anal cancer; CRS; Carcinomatosis; Epidermoid; HIPEC; Peritoneal metastases; Recurrent.