Metachronous Two Colonic Cancer Arising in Ascending and Sigmoid Colon without Performing Colostomy: A Case Report

Background: Metachronous colorectal cancer (CRC) is defined as the development of a second primary CRC at least 6 months after the treatment of the first CRC. The reported risk of metachronous CRC within 5 years after surgical resection of the colon and rectum ranges from 2 to 12%, and the risk factors include age, synchronous lesions, location and stage of the first CRC, and family history. Case presentation: We report a rare case of metachronous two colonic cancers arising in ascending and sigmoid colon, A 73-year-old female patient with a history of right hemicolectomy in 2010, developed a metachronous sigmoid cancer in 2023, treated with sigmoidectomy without performing total colectomy (only right hemicolectomy and sigmoidectomy in 13 years apart), followed by adjuvant chemotherapy and close follow-up. Conclusion: This case illustrates the occurrence of metachronous two colonic cancer arising in ascending and sigmoid adenocarcinoma, which is a rare and challenging scenario by avoiding colostomy and total colectomy.