Follow up after endoscopic resection in submucosal invasive colorectal cancers

Submucosal invasive colorectal cancers (SM‐CRC) have approximately a 10% chance of lymph node metastasis, which requires surgical resection including lymph node dissection for curative treatment. It is important to optimally survey patients after curative resection for SM‐CRC in order to detect early recurrence. In the present report, we principally show the long‐term outcomes after follow up of SM‐CRC resected endoscopically based on a report of the literature and our experience in Japan. The long‐term outcomes of low‐risk SM‐CRC endoscopically resected alone or high‐risk SM‐CRC with additional surgical resection with lymph node dissection are excellent. However, the risk of local recurrence of endoscopic resection alone in patients with high‐risk submucosal invasive cancer was significantly higher in rectal cancer as compared to similar colonic cancer. Patients with submucosal rectal cancer showing high‐risk pathological features are, therefore, strongly recommended to undergo additional treatment. We consider that longer follow up is required for patients with SM‐CRC because recurrence occurred relatively later in SM‐CRC compared to advanced colorectal cancer.