Short summary

In patients being diagnosed with very early colorectal tumors the cancer is often only a small malignant focus in a polyp. In some subgroups, patients have an increased risk of residual tumor either locally or in the lymphatics, and it must be decided whether to proceed with a segmental bowel resection or keep the patient under close observation. This study examines the management and outcome in Denmark over a 5 year period with a three year follow up period.

Rationale

Introduction Screening for bowel cancer has been implemented in several countries, leading to an increased number of patients being diagnosed with very early tumors. Often the cancer is only a small malignant focus in a polyp, macroscopically judged as benign and therefore removed endoscopically. In most cases, the patient will be cured by the endoscopic treatment alone. However, some subgroups of patients have an increased risk of residual tumor either locally or in the lymphatics, and it must be decided whether to proceed with a segmental bowel resection (so-called "completion resection"), or instead to keep the patient under close observation. Choosing the right treatment, once the pathological examination discloses a small cancer, constitutes a dilemma.

There is a problem of potential overtreatment universally and probably thousands of patients worldwide each year undergo operations that might potentially be avoided by better methods to correctly identify patients with an increased risk of recurrence.

Aim To elucidate current management of unexpected malignant colorectal polyps over a 5-year period in Denmark, with particular focus on predictors for the various treatment options, follow-up regimes, and outcomes in a nationwide population-based cohort study.

Description of the cohort

Inclusion criteria: All patients over 18 years of age, who had an unexpected malignant colorectal polyp removed endoscopically and in whom a CT-scan (and MRI if the malignant polyp was situated in the rectum) shows N0, M0.

Data and biological material

Data collection Data concerning patient, disease, treatment, short-term outcomes and histopathology will be retrieved from RKKP. Data concerning management and follow up will be retrieved from LPR. Missing data concerning local and completion resections will be retrieved from Patobank.

Collaborating researchers and departments

Department of Pathology, Vejle Hospital. Division

• Division of Population Medicine, Cardiff University, Wales, United Kingdom