More on Recurrence After Endoscopic Resection of T1 Colorectal Cancer: In Large Study, Only Rectal Location Predicted Recurrence
Douglas K. Rex, MD, MASGE, reviewing Arthursson V, et al. Endoscopy 2022 May 4.
Widely accepted predictors of local recurrence after endoscopic resection of T1 cancers include rectal location, positive resection margin, poor differentiation (PD), lymphovascular invasion (LVI), high-grade tumor budding, and deep submucosal invasion (SMI; >1 mm submucosal invasion depth). Recent studies have suggested that deep SMI, when not accompanied by other histologic risk factors, is likely not an independent risk for residual disease after endoscopic resection.
A large registry-based study from Sweden included 602 patients who had undergone endoscopic resection of a T1 colorectal cancer (CRC) and lacked synchronous CRC and neoadjuvant therapy. All lesions were nonpedunculated. All included patients had available information on SMI depth as well as follow-up for at least 1 year, with median follow-up 5 years. Overall, 65% of lesions were in the colon, 66% were Sm1 (a surrogate for superficial SMI), and 97% were well or moderately differentiated. In addition, only 3.4% had poor differentiation, 7.7% LVI, 1% perineural invasion, and 3.8% mucinous subtype. R0 resection was achieved in 77.4% of patients, though whether lesions were removed by endoscopic mucosal resection or endoscopic submucosal dissection was not available.
The total recurrence rate was 4.7%, and recurrence rates in patients with invasion depths of Sm1, Sm2, and Sm3 were 3.5%, 6.0%, and 8.3%, respectively. Multivariate analysis showed no impact on recurrence from invasion depth, LVI, tumor differentiation, or R0 resection. The only independent predictor of recurrence was rectal location, with an overall recurrence rate of 8.0% in rectal cases and 2.8% in colonic cases. Using the traditional risk factors outlined in the European Society of Gastrointestinal Endoscopy guidelines, recurrence occurred in 9% of high-risk patients and 2% of low-risk patients.
COMMENTNonpedunculated rectal lesions are now known to more likely be malignant than are colonic lesions, and these data indicate a higher risk of T1 cancer to recur after endoscopic resection, though the recurrence rate described here for T1 rectal cancer is actually lower than the risk of lymph node metastasis in some series of surgical resection of T1 cancer. Thus, there may be selection bias in the study. While LVI and PD were not poor prognostic indicators in this study, the literature generally still establishes them as indications for adjuvant surgery after endoscopic resection of T1 cancer. Further, endoscopic full-thickness resection of the site can be performed after obtaining a positive resection margin (or a free margin of less than 100 microns, or less than 1 mm, depending on the definition of free margin used) in order to acquire additional staging information.
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)
Arthursson V, Medic S, Syk I, Rönnow CF, Thorlacius H. Risk of recurrence after endoscopic resection of nonpedunculated T1 colorectal cancer. Endoscopy 2022 May 4. (Epub ahead of print) (https://doi.org/10.1055/a-1814-4434)
