Complete resection of recurrent anal canal cancer using endoscopic submucosal dissection and transanal resection: A case report.

Background: Early anal canal cancer is frequently treated with endoscopic submucosal dissection (ESD) to preserve anal function. However, if the lesion is in the anal canal, then significant difficulties such as bleeding and challenges associated with scope manipulation can arise.

Case Summary: A 70-year-old woman undergoing follow-up after transverse colon cancer surgery was diagnosed with anal canal cancer extending to the dentate line. The patient underwent a combination of ESD and transanal resection (TAR). The specimen was excised in pieces, which resulted in difficulty performing the pathological evaluation of the margins, especially on the anal side where TAR was performed and severe crushing was observed. Careful follow-up was performed, and local recurrence was observed 3 years postoperatively. Because the patient had superficial cancer without lymph node metastasis, local resection was performed again. The second treatment attempt was improved as follows: (1) TAR and ESD were performed appropriately based on the situation by the same physician; (2) A needle scalpel was used during TAR to prevent tissue crushing; and (3) The lesion borders were marked using ESD techniques before treatment. Complete resection was performed without complications.

Conclusion: Anal canal lesions can be safely and reliably removed when ESD and TAR are used appropriately.