New scoring system for the evaluation obstructive degrees based on computed tomography for obstructive colorectal cancer.

Background: The degree of obstruction plays an important role in decision-making for obstructive colorectal cancer (OCRC). The existing assessment still relies on the colorectal obstruction scoring system (CROSS) which is based on a comprehensive analysis of patients' complaints and eating conditions. The data collection relies on subjective descriptions and lacks objective parameters. Therefore, a scoring system for the evaluation of computed tomography-based obstructive degree (CTOD) is urgently required for OCRC.

Aim: To explore the relationship between CTOD and CROSS and to determine whether CTOD could affect the short-term and long-term prognosis.

Methods: Of 173 patients were enrolled. CTOD was obtained using k-means, the ratio of proximal to distal obstruction, and the proportion of nonparenchymal areas at the site of obstruction. CTOD was integrated with the CROSS to analyze the effect of emergency intervention on complications. Short-term and long-term outcomes were compared between the groups.

Results: CTOD severe obstruction (CTOD grade 3) was an independent risk factor [odds ratio (OR) = 3.390, 95% confidence interval (CI): 1.340-8.570, = 0.010] multivariate analysis of short-term outcomes, while CROSS grade was not. In the CTOD-CROSS grade system, for the non-severe obstructive (CTOD 1-2 to CROSS 1-4) group, the complication rate of emergency interventions was significantly higher than that of non-emergency interventions (71.4% 41.8%, = 0.040). The postoperative pneumonia rate was higher in the emergency intervention group than in the non-severe obstructive group (35.7% 8.9%, = 0.020). However, CTOD grade was not an independent risk factor of overall survival and progression-free survival.

Conclusion: CTOD was useful in preoperative decision-making to avoid unnecessary emergency interventions and complications.