Metachronous Colorectal Tumors in Patients with Regular Colonoscopic Follow-examinations

Metachronous colorectal tumors are common colonoscopic finding. Metachronous colorectal adenomas are detected in 20-70.3% of patients, but metachronous colorectal carcinoma (CRC) in 0.5-9% patiens. In this prospective study, 120 patients (80 male, 40 female, mean age 57.9, range 31-77) were evaluated for metachronous tumors after colonoscopic polypectomy for benign single/multiple colorectal tumors or colorectal surgery for CRC. There were 34 (28.33%) patients in whom 58 metachronous tumors (benign and malignant) were detected 12-48 months after previous intervention, localised in different colorectal segments. Metachronous tumors were more frequent in patients with initial multiple tumors than in patients with initial single colorectal tumor. Most of the tumors were found within 24 months from colonoscopic polypectomy or colorectal surgery. It is supposed that initial advanced adenoma and malignant alterated adenoma could be adittional risk factors for development of metachronous adenoma. Metachronous CRC were detected in 6.47-7.69% metachronous tumors in patients originating from different initial groups. Regular colonoscopic follow-up examinations after colonoscopic polypectomy or colorectal surgery for CRC are required. Follow-up colonoscopies may detect colorectal adenomas with different degrees of dysplastic changes, but colonoscopic polypectomy may prevent transformation of adenoma to CRC (adenoma carcinoma sequence). In the same time follow-up colonoscopies may detect metachronous CRC in early stage, when prognosis after colorectal surgery is much better than after colorectal surgery for advanced metachronous CRC.