Endoscopic submucosal dissection to treat squamous cell carcinoma in situ of the anal canal.

Background and Aims: The standard treatment for invasive squamous cell anal cancer is chemoradiation treatment. However, treatment options for high-grade dysplasia (squamous cell cancer in situ) are either surgical excision or topical treatment modalities. There are a few case reports, mainly from Japan, about resecting early squamous cell anal cancer (high-grade dysplasia/carcinoma in situ) by endoscopic submucosal dissection. We present a case series of 3 patients from a western hemisphere population with squamous carcinoma in situ of the anal canal resected with endoscopic submucosal dissection (ESD). Methods: This is a retrospective series of 3 patients from a western hemisphere population with squamous carcinoma in situ of the anal canal resected with ESD. All patients were referred from the oncology team after declining surgical excision. Results: Microscopically margin-negative en bloc resection was achieved in all patients. All patients were free from dysplasia or cancer on their latest endoscopic surveillance, ranging from 10 months to 26 months after ESD. One patient had a small lesion on follow-up 3 months after ESD that was removed by a curative EMR. There were no immediate or delayed adverse events. Conclusions: ESD can be used to resect squamous cell carcinoma in situ of the anal canal. Larger studies with long-term follow-up are needed to evaluate the role of ESD in early squamous cell anal cancer and to compare it with other modalities of treatment.