Colorectal cancer (CRC) is the second leading cause of cancer death worldwide, surpassed only by lung cancer. Several countries, including the UK and the US, recommend bowel cancer screening for adults starting in middle age in order to prevent CRC or detect it early. A study published in the British Medical Journal in early May found that having a parent or sibling with a history of colorectal polyps may increase one’s risk for CRC, particularly early-onset CRC. These results could inform future changes to screening recommendations.
Song and colleagues linked information from several nationwide Swedish registries to study family history of colorectal polyps and CRC risk in 68,060 CRC cases and 333,753 controls. The study authors found that, even after accounting for family history of CRC, the risk of CRC was 35% to 45% higher for those with a history of polyps in first-degree relatives (parents and siblings). Furthermore, the risk of early-onset CRC diagnosed before age 50 years was 3.3 (2.0–5.4) times higher for those with two or more first-degree relatives with polyps.
In the UK, CRC screening is recommended for adults ages 50 years and older. However, the British Society of Gastroenterology only considers the family history of CRC, not polyps, in their screening guidelines. GlobalData epidemiologists forecast that the diagnosed incident cases of CRC will increase in the UK, reaching nearly 50,000 cases in 2028 (as shown in Figure 1). If the results of the Swedish study prove replicable in other populations, screening guidelines in the UK could be expanded to include people who have a parent or sibling with polyps. An expansion of the CRC screening recommendations would likely lead to increased case identification and thus an increase in new CRC cases in the UK.
In October 2020, the US Preventive Services Task Force (USPSTF) recommended lowering the CRC screening age of adults from 50 years to 45 years. The results of the study from Song and colleagues could help inform a more risk-based approach for screening in younger adults for the prevention of early-onset CRC. GlobalData epidemiologists suggest that additional large, registry-based studies in other populations should be conducted to confirm the relationship between CRC risk and colorectal polyps in close relatives.