Background/Objectives: Oligopolyposis is a rare condition characterized by 10 to 100 adenomas in the colon. We aimed to investigate the clinical and endoscopic features of patients with oligopolyposis by comparing patients who carried pathogenic mutations and those who did not. Methods: This retrospective study included patients with a cumulative count of 10–100 adenomas found in the colon, at a single center. Clinical, endoscopic, and genetic data were analyzed. Results: A total of 155 patients were identified as having oligopolyposis. Genetic testing using a multigene panel was performed among 85 (55%) patients, while founder or family mutation testing was performed among 7 (4.5%) patients. No genetic testing was carried out in 63 (40.5%) patients. Pathogenic polyposis-related mutations were identified in 14 (16%) out of 85 patients who underwent genetic testing. Among these, seven (50%) mutations were found in the APC gene and seven (50%) in the MUTYH gene. A significantly higher proportion of mutation carriers were of Arab ethnicity (35.7% vs. 4.2%, p < 0.001). There was no significant difference between carriers and non-carriers with regard to family history of polyps or cancer. Colorectal cancer was found to be the initial presentation in three (21%) carriers and five (7%) non-carriers. Colonic surgeries were reported among 4 (28.6%) carriers and 13 (18.6%) non-carriers. No significant differences in the rates of colorectal cancer or death were observed between carriers and non-carriers. Conclusions: Only a small proportion of patients with oligopolyposis were found to be mutation carriers, with significant ethnic differences in mutation frequency but no notable differences in clinical features, colorectal cancer rates, or mortality.

Background/Objectives: Colorectal cancer (CRC) is the third most common cancer worldwide. Accordingly, we aimed to investigate the frequency, types, and timelines of other cancers in patients diagnosed with CRC. Methods: Patients diagnosed with CRC between 1999 and 2023 were retrospectively included. We collected data on the demographics and diagnosis of any additional cancer, either prior to or following the CRC diagnosis. Data were retrieved from the Clalit database using the MDClone platform. Results: A total of 65,774 CRC patients were identified between 1999 and 2023. A second primary malignancy (SPM) was diagnosed in 13,679 patients (21%). Being female, smoking, and having chronic obstructive pulmonary disease were more frequent among patients with a SPM. Breast, prostate, and lung cancers were the most prevalent SPMs. The risk of developing SPM was highest during the first three years after CRC diagnosis, especially with respect to lung cancer, whereas the majority of breast and prostate cancers were diagnosed during the three years before CRC; the cumulative standardized incidence ratio was calculated to be 4.1 for any cancer. Conclusions: CRC patients have an increased second primary cancer. Patients diagnosed with CRC should be encouraged to undergo screening for other cancers, and those with Lynch-related cancers should be investigated for the syndrome. Patients with a diagnosis of breast or prostate cancer should be considered for colonoscopy screening.