You Removed a Small Lesion With High-grade Dysplasia or Cancer Using a Cold Snare, Now What?
Douglas K. Rex, MD, MASGE, reviewing Inoki K, et al. J Gastroenterol 2023 Mar 20.
Cold snare polypectomy is now the resection method of choice for colorectal lesions ≤10 mm in size. The risk of resecting a cancerous lesion in this size range is extremely low but not zero.
This study from Japan describes 156 lesions removed from 155 patients by cold snare polypectomy. The lesions were collected over 6 years from 22 centers and found to have either high-grade dysplasia (HGD; including intramucosal cancer) or submucosal invasive cancer (SMIC; n=9). The median lesion size was 6 mm, ranging from 2 to 18 mm, and 70.5% were protruded-type lesions.
There were 69 cases and 70 lesions in which the cold snare resection was considered curative, ie, clear margins, no HGD or superficial SMIC, and without poor differentiation, lymphovascular invasion (LVI), or high-grade tumor budding. These cases were followed up later, and the scar was identified in only 22 cases (31.4%). Only one case had residual tissue on the scar, and it was resected endoscopically.
Borderline cases (n=75) were the same as curative, but there was an indefinite deep or lateral margin on the cold snare specimen. Scars were found at follow-up in 41 cases (54.7%), and 7 patients had dysplastic lesions at endoscopic or surgical resection, but none had cancer.
Noncurative resections (n=11) had a positive margin, deep submucosal invasion (SMI), LVI, or high-grade tumor budding. Ten cases (90.9%) had the scar identified, and 3 had neoplasia identified. One had SMI with a positive vertical margin on the specimen, and follow-up showed a small submucosal lump with normal overlying mucosa, leading to surgical resection that showed cancer.
COMMENTOne problem with cold snare resection relative to hot snare resection is that cuts are more superficial. This study is a reminder that even small lesions with morphology or a surface pattern suggesting cancer should be resected with electrocautery. If HGD is identified in cold snare specimens, these data suggest we should remain calm, as the risk of residual dysplasia with SMIC is extremely low. Review by a second pathologist could be appropriate, as dysplasia grade in colon polyps is subject to interobserver variation among pathologists. If SMIC is reported in a cold snare specimen, or there is HGD that is confirmed and with a positive margin, a repeat colonoscopy within a few weeks can typically identify the site. A biopsy of the site could be performed, or perhaps, better yet, the site could be resected with a hot snare or full-thickness device.
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.
CITATION(S)
Inoki K, Takamaru H, Furuhashi H, et al. Management of colorectal high-grade dysplasia or cancer resected by cold snare polypectomy: a multicenter exploratory study. J Gastroenterol 2023 Mar 20. (Epub ahead of print) (https://doi.org/10.1007/s00535-023-01980-1)
