T1 Colorectal Cancer With Free Resection Margins Between 0.1 and 1 mm: High-Grade Tumor Budding Makes the Difference in Recurrence Risk
Douglas K. Rex, MD, MASGE, reviewing Gijsbers KM, et al. Endosc Int Open 2022 Apr.
A free resection margin, often interpreted as >1 mm between cancer and the resection line, is an independent predictor of low risk for recurrent cancer during follow-up or absent residual cancer in the bowel wall and lymph node metastases when adjuvant surgical resection is used.
This study evaluated the absolute risk of residual cancer in patients with a margin ranging in size from 0.1 mm to 1 mm and no other major histologic risk factors, including lymphovascular invasion (LVI) and poor differentiation (PD).
In 11 Dutch hospitals, data were collected from consecutive patients who underwent local excision of T1 colorectal cancers (CRCs) between 2014 and 2017. The lesions could be either pedunculated or nonpedunculated, and about 75% of resections were completed by en bloc endoscopic mucosal resection (EMR) or polypectomy, with the remainder removed by piecemeal EMR, endoscopic submucosal dissection, transanal resection, or full-thickness resection. Local recurrence was defined as a residual polyp in an adjuvant resection or identified during follow-up.
There were 171 lesions with resection margins of 0.1 to 1 mm and 351 with resection margins >1 mm. The overall local intramural residual cancer rate was 2.9% for lesions with margins of 0.1 to 1 mm and 0.6% for lesions with margins >1 mm. Neither resection technique nor colon location affected the recurrence rate, but there were no recurrences among 48 pedunculated lesions with margins of 0.1 to 1 mm. In the nonpedunculated group with a close margin, 4.1% had a local recurrence and 8.1% developed metastasis.
Most pathology reports did not describe whether tumor budding was present, so slides had to be reviewed for tumor budding. In the group with local intramural recurrence, 80% had high-grade tumor budding. In the group without local recurrence or metastasis, high-grade tumor budding was present in 16.2%. In the group with margins of 0.1 to 1 mm without high-grade tumor budding, local recurrence was identified in 1 patient (0.8%) and metastasis in 4 patients (3.1%). These risks were similar to the risks in patients with resection margins >1 mm.
Note to readers: At the time we reviewed this paper, its publisher noted that it was not in final form and that subsequent changes might be made.
Gijsbers KM, van der Schee L, van Veen T, et al. Impact of ≥ 0.1-mm free resection margins on local intramural residual cancer after local excision of T1 colorectal cancer. Endosc Int Open 2022;10:E282-290. (https://doi.org/10.1055/a-1736-6960)