Tumor Seeding at Colonoscopy: A Cause of Metachronous Colorectal Cancer?

Seeding of colorectal cancer (CRC) cells due to manipulation of the primary tumor during colonoscopy may contribute to metachronous CRC after surgical resection, but this has not been well studied.

Researchers from the Netherlands identified 22 metachronous CRC cases that were diagnosed 6 to 42 months after surgical resection. In five cases, the likely cause was attributed to tumor seeding because biopsy or polypectomy occurred at the anatomic location of the subsequently detected metachronous CRC after endoscopic manipulation of the primary tumor. For three patients with available tissue, the molecular signatures of the primary and metachronous CRC were identical.

In a separate review of 2147 surgically resected CRC cases, the risk for tumor…