Exploration of between-hospital variation and the basis for decision making in management of malignant colorectal...

Finding an unexpected carcinoma in an endoscopically resected colorectal polyp poses a dilemma regarding the subsequent management strategy. Proceeding to surgery with formal segmental bowel resection is associated with a low recurrence risk but substantial morbidity and mortality, whereas surveillance without surgery entails low morbidity but a higher risk of recurrence. Clinical guidelines are based on histopathological risk factors (HRF), but pathology data are often incomplete, and national databases have revealed marked practice variation between hospitals. We aimed to explore between-hospital variation and the basis for treatment decisions after endoscopic resection of malignant colorectal polyps in Denmark.

A national cohort of colorectal cancer patients from 2016-2020 was extracted from national clinical and pathology registers. Patients undergoing local resection only (surveillance group) and local resection followed by subsequent bowel resection (surgery group) were compared in uni- and multivariable analyses stratified by reported HRF. Patient- and hospital-related factors were included as covariates with particular focus on between-hospital variation.

Overall, 2,188 patients were analyzed, 1,277 in the surveillance group and 911 in the surgery group. Multivariable analyses showed that male sex, older age, comorbidity, lower performance status and left colon or rectum tumor location were significantly associated with surveillance, most even in the presence of HRF. Long higher education and certain hospitals were significantly associated with bowel resection. Predictors of bowel resection despite absence of HRF were certain hospitals and active smoking. In the surgery group without HRF conclusive information was missing in up to 70% of the pathology reports regarding certain HRF. Preoperative image-based overstaging may have resulted in a higher rate of cancer-free specimens. Overall, 63% of bowel resection specimens were cancer-free.

We found marked between-hospital practice variation in management strategy for malignant colorectal polyps, even in adjusted analyses. Among the probable explanations were missing or incomplete pathology data and suspicion of more advanced disease based on clinical staging. Consistency in hospital practice, completeness of the pathology reports and overall better collaboration of the multidisciplinary team are needed to improve the decision-making process in patients with endoscopically removed malignant colorectal polyps.