A structured conversion score to guide oncologic colectomy during combined endoscopic-laparoscopic surgery for...

Management of complex colonic polyps with benign preoperative biopsy findings remains challenging when endoscopic resection is technically difficult or oncologic risk is uncertain. Combined endoscopic-laparoscopic surgery (CELS) offers an organ-preserving alternative to oncologic colectomy (OC), yet clear criteria for intraoperative decision-making are lacking. This study aimed to identify predictors of conversion from CELS to OC and malignant pathology and to develop an intraoperative risk score to guide escalation.

A single-center retrospective cohort study included consecutive patients treated between 2014 and 2024 for complex colonic polyps with benign preoperative biopsy findings using an endoscopy-first strategy requiring laparoscopic assistance. The primary endpoint was conversion to OC. Secondary endpoints included pathologic malignancy and ≥ T2 disease. Clinically relevant preoperative and intraoperative variables were analyzed using Firth penalized logistic regression. Internal validation was performed using bootstrap resampling. A 10-point CELS-OC score was derived and integrated into a stepwise operative algorithm.

Seventy patients were included, of whom 25 (35.7%) required conversion to OC. Final pathology revealed malignancy in 20 patients (28.6%). Ulceration or depression (aOR 19.15, 95% CI 3.45-106.36; p < 0.001), lesion size ≥ 40 mm (aOR 6.40, 95% CI 1.35-30.33; p = 0.019), and the non-lifting sign (aOR 5.36, 95% CI 1.05-27.44; p = 0.044) were independently associated with conversion. Ulceration or depression remained predictive of malignancy (aOR 13.07, 95% CI 3.10-55.04; p = 0.001). The score demonstrated strong discrimination for OC conversion (AUC 0.928) and malignancy (AUC 0.874). High-risk lesions (≥ 7 points) had OC conversion and malignancy rates of 93.8% and 75.0%, respectively.

In complex colonic polyps with benign biopsy findings, specific morphologic and intraoperative features are associated with conversion to OC and malignant pathology. The CELS-OC score integrates these predictors into a structured intraoperative framework that may improve organ-preserving selection while maintaining oncologic safety. External validation is needed.