Dual Presence of Adenomas and Serrated Polyps Increases Colorectal Cancer Risk Fivefold, Study Finds

New research from Flinders University finds that having both adenomas and serrated polyps increases cancer risk fivefold. Early colonoscopy detection is vital.

By: AXL Media

Published: Mar 13, 2026, 5:25 PM EDT

Source: Information for this report was sourced from Flinders University

The Compounding Risk of Synchronous Bowel Lesions

Medical researchers in South Australia have identified a critical correlation between the simultaneous presence of two distinct types of bowel polyps and an accelerated risk of malignancy. The study, conducted by experts at Flinders University and Flinders Medical Centre, indicates that patients harboring both adenomas and serrated polyps face a fivefold increase in the likelihood of developing advanced precancerous transformations. This specific combination, referred to as synchronous lesions, appears to create a cumulative threat level that far exceeds the risk profile of patients presenting with only a single variety of growth.

Large Scale Analysis of Colonoscopy Records

The findings are the result of an extensive review involving more than 8,400 colonoscopy records, making it one of the most comprehensive investigations into polyp interaction to date. According to Dr. Molla Wassie, the lead author from the FHMRI Bowel Health Service, the data suggests that this high risk combination is significantly more prevalent than the medical community previously estimated. The analysis revealed that nearly 50 percent of patients diagnosed with serrated polyps also carried adenomas, a discovery that carries profound implications for standard diagnostic procedures and patient risk stratification.

Parallel Pathways to Colorectal Malignancy

The research supports an emerging international consensus that adenomas and serrated polyps follow separate biological pathways toward cancer, yet can remain active within a patient at the same time. This dual pathway theory explains why the presence of both lesions so drastically increases the probability of serious disease. According to the study, published in the journal Clinical Gastroenterology and Hepatology, the interaction of these separate evolutionary tracks means that a patient's bowel environment can facilitate multiple routes to oncogenesis simultaneously, requiring a more nuanced approach to preventative care.