Vertical margin distance in T1 colorectal carcinoma resected by endoscopic submucosal dissection affects prognosis after additional surgery.

PURPOSE : A vertical margin (VM) distance of < 500 µm is a risk factor for recurrence in patients with T1 colorectal carcinoma (CRC) resected by endoscopy. We aimed to determine the effects of the VM distance on the recurrence and prognosis of T1 CRC.

Methods: We enrolled 168 patients with T1 CRC who underwent additional surgery after endoscopic submucosal dissection (ESD) at multiple centers between 2008 and 2016. None of the patients were followed up for < 5 years. The enrolled 168 patients were classified into patients with VM distance of < 500 µm including positive VM (n = 72 [43%], VM distance < 500 µm group) and patients with VM distance of ≥ 500 µm (n = 96 [57%], VM distance ≥ 500 µm group). The clinicopathological features, recurrence rates, and prognoses were compared between the groups using propensity-score matching (PSM).

Results: Tumors recurred in eight of the 168 patients (5%) with VM distance < 500 µm. After PSM, the rate of overall recurrence and local recurrence in the VM distance < 500 µm group were significantly higher than those in the VM distance ≥ 500 µm group. The 5-year recurrence-free survival rate was significantly higher in the VM distance ≥ 500 µm group than that in VM distance < 500 µm group after PSM (100% vs. 89%, p < 0.012).

Conclusions: Complete en bloc resection of T1 CRC via ESD must include a sufficient amount of SM to reduce the risk of metastasis and recurrence after additional surgery.