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T1 colorectal cancers that infiltrate the submucosa have a risk of lymph node metastasis of about 10%, which is higher than in the colon. The criteria for additional treatment after endoscopic resection have been modified in the latest version of the French recommendations, opening up the possibility of curative resection in the case of lesions deeply invading the submucosa (sm2, sm3), provided there are no histopronostic factors associated with a poor prognosis. These factors include lymphovascular and neural invasion, budding ≥ 2, and poor tumor differentiation. Anatomopathological examination of the endoscopic specimen is therefore essential and a second opinion by an experienced pathologist may be recommended. In these cases, a monobloc resection is required, which has been made possible by advances in submucosal dissection techniques. The use of artificial intelligence, immunoscore, and nomograms may help to predict the risk of lymph node metastasis and tailor treatment approaches according to age and comorbidities.