Prevalence and Management of Cancer of the Rectal Stump after Total Colectomy and Rectal Sparing in Patients with Familial Polyposis: Results from a Registry-Based Study

Simple Summary Prophylactic total colectomy with ileo-rectal anastomosis (IRA) is the surgical approach that guarantees a better quality of life compared to proctocolectomy and ileo-anal anastomosis (IPAA) in familial adenomatous polyposis (FAP) patients. However, previous studies have warned about the high risk of cancer of the rectal stump, especially considering the young age of these patients. This is a retrospective study whose aim was to assess both clinical and surgical features of patients who developed cancer of the rectal stump. The data reported show that IRA is a safe approach from an oncological perspective. Since early tumors of the rectal stump may be easily detected via endoscopic or minimally invasive approaches, strict surveillance is necessary. Background: The balance between quality of life and colorectal cancer risk in familial adenomatous polyposis (FAP) patients is of primary importance. A cut-off of less than 30 polyps under 1 cm of diameter in the rectum has been used as an indication for performing ileo-rectal anastomosis (IRA) in terms of lower rectal cancer risk. This study aimed to assess clinical and surgical features of FAP patients who developed cancer of the rectal stump. Methods: This retrospective study included all FAP patients who underwent total colectomy/IRA from 1977 to 2021 and developed subsequent rectal cancer. Patients' features were reported using descriptive statistics by considering the overall case series and within pre-specified classes of age (<20, 20-30, and >30 years) at first surgery. Results: Among the 715 FAP patients, 47 (6.57%, 95% confidence interval: 4.87; 8.65) developed cancer in the rectal stump during follow-up. In total, 57.45% of the population were male and 38.30% were proband. The median interval between surgery and the occurrence of rectal cancer was 13 years. This interval was wider in the youngest group (p-value: 0.012) than the oldest ones. Twelve patients (25.53%) received an endoscopic or minimally invasive resection. Amongst them, 61.70% were Dukes stage A cancers. Conclusions: There is a definite risk of rectal cancer after total colectomy/IRA; however, the time interval from the index procedure to cancer developing is long. Minimally invasive and endoscopic treatments should be the procedures of choice in patients with early stage cancers.