Granular Laterally Spreading Tumors With Nodule: Rectal Location and at Least 4-cm Size Warrant en Bloc Resection

Granular Laterally Spreading Tumors With Nodule: Rectal Location and at Least 4-cm Size Warrant en Bloc Resection

Douglas K. Rex, MD, MASGE, reviewing D’Amico F, et al. Clin Gastroenterol Hepatol 2020 Jul 17.

Granular laterally spreading tumors (G-LST) in the colorectum are more common than nongranular lesions, less likely to have cancer, and in general, easier to remove because of a lower prevalence of submucosal fibrosis. However, within the granular group, lesions with a discrete large nodule, often called “mixed nodular” or “GM-LST,” have a higher risk of cancer. In any LST with a substantial risk of submucosal invasive cancer (SMIC), the rationale for en bloc resection increases because patients with only superficial invasion (<1000 microns) and no other unfavorable histologic features may be able to avoid surgery after en bloc resection. 

In a multicenter Italian study, 693 lesions with GM-LST morphology were prospectively assessed. The overall risk of covert SMIC was 9.5%. Two-thirds of the lesions with covert SMIC were in the rectum, and two-thirds were ≥4 cm in size. The overall risk of covert SMIC in rectal lesions ≥4 cm in size was 22%. Thus, the number needed to treat (NNT) to remove one lesion with SMIC in that group was 5. For lesions either above the rectum or <4 cm in size, the NNT to remove one lesion with covert SMIC ranged from 13 to 20.

Douglas K. Rex, MD, FASGE


En bloc resection of lesions ≥4 cm in size requires endoscopic submucosal dissection (ESD). This study suggests that GM-LST ≥4 cm in size and in the rectum are a good target set of lesions for ESD, a finding that dovetails nicely with the clinical observation that ESD is safer and easier to do in the rectum than the colon. In addition, surgical procedures performed on the rectum have greater morbidity than colonic resections. The actual NNT to prevent surgery in GM-LSTs ≥4 cm in size may be greater than 5 since some patients with covert SMIC will have deep (>1000 microns) SMIC and others will have other unfavorable histologic features, such as poor differentiation, lymphovascular invasion, and tumor budding. Nevertheless, this study helps define a set of colorectal lesions for which the cost and risks of ESD are justified.

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.


D’Amico F, Amato A, Iannone A, et al. Risk of covert submucosal cancer in patients with granular mixed laterally spreading tumors. Clin Gastroenterol Hepatol 2020 Jul 17. (Epub ahead of print) (

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