Deep submucosal invasion as a risk factor for recurrence after endoscopic submucosal dissection for T1 colorectal cancer

We would like to thank Dr. Saito for the reference to our manuscript [1] in his Editorial [2] focusing on deep submucosal invasion as a risk factor for lymph node metastasis (LNM). We would like to elaborate.

We agree with Dr. Saito that local recurrence and LNM of cancer are paramount. While our follow-up for intramural recurrence was appropriate, we did acknowledge that the assessment of late metastatic disease warrants prospective long-term studies [3] [4]. We agree that one of the conclusions of our study – low recurrence for T1 lesions with deep submucosal invasion – may be impacted by the limited case numbers and hence the data are exploratory and not statistically confirmatory.

Nevertheless, the data target a field with rising clinical interest. Dr. Saito referred to 5 %–10 % recurrence rates for lesions with deep submucosal invasion only [3], therefore advocating for surgery for such lesion. Comparisons with our study are however not straightforward owing to variations in the definitions, patients, outcomes, and follow-up, plus there was no subanalysis of patients with deep submucosal invasion without other risk factors. Three patients treated by ESD with deep submucosal invasion had recurrence, but all of them had other risk factors. In the same study, no relationship between deep submucosal invasion and recurrence was found [3], while other studies have demonstrated a 0 % risk of LNM in the same group of patients [4] [5], consistent with what was found in our study. That is why new ESD variants, such as intermuscular dissection, are emerging as potential curative techniques for select cases.

One of our main messages is that clinical algorithms combining and weighing the different risk factors with each other are the way to better select patients with a noncurative ESD for complementary treatment, especially in those who are high risk surgical candidates. Certainly, prospective confirmatory data are required before the indication for complementary surgery based on the cutoff of a 1000-μm depth of submucosal invasion is re-evaluated.

Publication History

Article published online:
29 August 2023

• References

• 1 Santos-Antunes J, Pioche M, Ramos-Zabala F. et al. Risk of residual neoplasia after a noncurative colorectal endoscopic submucosal dissection for malignant lesions: a multinational study. Endoscopy 2023; 55: 235-244
• 2 Saito Y. Pathologic sm2 carries a moderate risk of metastases even without other unfavorable factors, but positive horizontal margins have low local recurrence risk after en bloc resection. Endoscopy 2023; 55: 252-254
• 3 Takamaru H, Saito Y, Sekiguchi M. et al. Endoscopic resection before surgery does not affect the recurrence rate in patients with high-risk T1 colorectal cancer. Clin Transl Gastroenterol 2021; 12: e00336
• 4 Kouyama Y, Kudo S, Miyachi H. et al. Practical problems of measuring depth of submucosal invasion in T1 colorectal carcinomas. Int J Colorectal Dis 2016; 31: 137-146
• 5 Naito A, Iwamoto K, Ohtsuka M. et al. Risk factors for lymph node metastasis in pathological T1b colorectal cancer. In Vivo 2021; 35: 987-991