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.