Assessment of Incidence of Metachronous Neoplasms after Surgical Resection of Colorectal Cancer

Background: Colorectal cancer (CRC) is among the most common malignancies worldwide, with significant morbidity and mortality. Despite curative surgical resection, patients remain at risk of developing metachronous colorectal neoplasms. Aim: This study aims to determine the incidence and risk factors of metachronous CRC following curative surgery. Methods: In this retrospective cohort study, 100 patients who underwent curative CRC surgery and were followed for six months. Patients with total colectomy, metastatic CRC, or palliative surgeries were excluded. Surveillance included colonoscopy, CT imaging, and laboratory investigations. Patients were categorized into two groups: recurrence (Group 2, n = 10) and no recurrence (Group 1, n = 90). Results: The incidence of metachronous CRC was 10%, equally distributed as polyps (5%) and masses (5%). Recurrence occurred most frequently at the anastomotic site (40%). Adenocarcinoma was the most common histopathology (50%). No significant differences were found between groups regarding demographic or surgical variables. However, diabetes mellitus (DM) was significantly associated with recurrence (60% in Group 2 vs. 26.7% in Group 1, p = 0.048), and multivariate analysis confirmed DM as an independent predictor (OR = 10.619; 95% CI: 1.002–112.557; p = 0.049). Laboratory parameters showed significant postoperative changes, especially in liver and renal function tests, but these did not independently predict recurrence. Conclusion: Metachronous CRC occurred in 10% of patients within six months post-resection. Diabetes mellitus emerged as a significant independent predictor. Vigilant surveillance, especially in diabetic patients, is essential to detect early metachronous lesions.