Applicability of the Scottish Screen-detected Polyp Cancer Study (SSPoCS) Algorithm in a multicentric cohort in the management of malignant colorectal polyps

Aims Robust evidence regarding the management after endoscopic resection of malignant colorectal polyps (MCP) is lacking. Inconsistencies in reporting on potential prognostic factors, such as submucosal invasion depth and tumor budding, hinder the decision process. To address these issues, the Scottish Screen-detected Polyp Cancer Study (SSPoCS) introduced an algorithm based in two easily obtainable variables: resection margin and lymphovascular invasion. This study aims to assess the applicability of the SSPoCS algorithm in a Portuguese multicentric cohort.

Methods Endoscopically resected MCP in five centers from 2017 to 2020 were included. The main outcome was residual/recurrent malignancy (RRM), defined as any of the following: [1] residual intramural or lymph node malignancy in the surgical specimen after completion surgery; [2] local or systemic recurrent disease in conservatively managed patients.

Results Two-hundred-and-eleven patients were included (mean age: 68.6±10.4 years; male gender: 65.4%); 121 underwent completion surgery while 90 remained in surveillance. Thirty-two patients (15.2%) experienced RRM: 27 displayed residual malignancy in the surgical specimen and five developed recurrent disease. According to SSPoCS algorithm: 119 patients were classified as having low-risk of residual disease, six of whom displayed RRM (5.0%); 10 as medium-risk, with one having RRM (10.0%); and 82 as high-risk, 25 of whom experienced RRM (30.5%). Lesions classified as low-risk showed a negative predictive value (NPV) of 95.0% to exclude RRM. The algorithm demonstrated good accuracy in predicting RRM in a Receiver Operating Characteristic curve analysis (AUC: 0.74, 95% CI: 0.65-0.83, p<0.001). In lesions classified as low-risk, all six cases of RRM displayed deep submucosal invasion (DSI:>1000 µm). In a multivariate analysis, piecemeal resection was the only independent variable associated with RRM (OR: 1.90; 95% CI: 1.02-3.10; p<0.001).

Conclusions The SSPoCS algorithm revealed good accuracy in predicting residual/recurrent malignancy with a NPV of 95.0% to exclude RRM in low-risk lesions. All cases of RRM following low-risk resections showed DSI, suggesting that invasion depth might be relevant for the decision-making process.

 

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Conflicts of interest

The authors certify that there is no conflict of interest with any financial organization regarding the material discussed in the manuscript.

• References

• 1 Richards C, Levic K, Fischer J. et al. International validation of a risk prediction algorithm for patients with malignant colorectal polyps. Colorectal Dis 2020; 22 (12) 2105-2113
• 2 Richards CH, Ventham NT, Mansouri D. et al. Scottish Surgical Research Group. An evidence-based treatment algorithm for colorectal polyp cancers: results from the Scottish Screen-detected Polyp Cancer Study (SSPoCS). Gut 2018; 67 (02) 299-306

Publikationsverlauf

Artikel online veröffentlicht:
15. April 2024