How safe is local resection of T1 CRC? It depends on risk factors!

Review by Prof. Eamonn Quigley (USA)

Study Summary 

As colorectal cancer becomes more widespread worldwide and techniques for endoscopic resection of apparently localized cancers (including endoscopic mucosal resection, EMR and endoscopic submucosal dissection, ESD) are more widely applied the question inevitably arises: when is local resection adequate and curative? In this study 4,667 patients with T1 CRC recruited from 27 institutions in Japan over a 7-year period were retrospectively assessed over a follow-up period of up to 12 years for lymph node metastases, recurrence and survival. At baseline, all tumors were assessed for the presence of the following risk factors for lymph node metastases:

• Submucosal resection margin
• Tumor histologic grade
• Submucosal invasion depth
• Lympho-vascular invasion
• Tumor budding

Furthermore, a positive vertical margin was regarded as an absolute indication for surgery as was the presence of at least one of the following: high-risk histology, deep submucosal invasion, high budding grade and lympho-vascular invasion, provided, of course that the individual was judged as fit for surgery. After initial assessment, 1,257 underwent local resection alone, 1,512 a local resection followed by additional surgery and 1,898 went directly to surgery. The presence of the above listed risk factors proved critical in predicting outcome.

In those who underwent surgery (either immediate or following local resection) the overall risk for lymph node metastases was 10% but was much higher in those with risk factors: 10.8% vs 1.8%. The same applied for risk of recurrence among those who underwent local resection alone: 3.6% for those who had risk factors in comparison to a mere 0.4% among those without. Furthermore, these individuals also enjoyed a 99.6% 5-year disease-free 5-year survival rate. In contrast, those who underwent local resection alone but has baseline risk factors disease-free 5-year survival was lower (95%) than in the surgical groups (97 and 98%).

Commentary 

This large and truly “real world” study provides some very important conclusions and with them guidance for the endoscopic and surgical management of localized CRC. The histologic criteria which were developed by the Japanese Society for Cancer of the Colon and Rectum (JSCCR) as risk factors for lymph node metastases proved highly predictive of all outcomes. This study was retrospective, performed in a country where there is ready access to advanced endoscopic skills and techniques and involved meticulous histologic assessments. Nevertheless, the bottom line is clear: if the JSCCR are present, surgery, either immediate or performed after local resection, is indicated. If absent, the outcome following local resection alone is excellent.

Citation

Oka S, Tanaka S, Kajiwara Y, et al. Treatment decision for locally resected T1 colorectal carcinoma – verification of the Japanese guideline criteria for additional surgery based on long-term clinical outcomes. Am J Gastroenterol 2024;119:2019-27.

View past News You Can Use commentaries