Link found between family history of colorectal polyps, risk for colorectal cancer
“In contrast with the established increased risk associated with a family history of CRC, it remains unclear whether those with a family history of colorectal polyps have an increased risk of CRC. As a result, available screening recommendations are discrepant for individuals with a family history of polyps,” Mingyang Song, MBBs, ScD, department of epidemiology and nutrition at the Harvard T.H. Chan School of Public Health, and colleagues wrote. “Given the higher prevalence of polyps than CRC associated with the increasing uptake of endoscopic screening, a better understanding about the influence of family history of polyps on CRC risk is critical to improve current screening recommendations.”
In a case control study, researchers analyzed 68,060 patients with CRC and 333,753 matched control patients to assess the risk for CRC in first-degree relatives of patients with precursor lesions (8.4% vs. 5.7%, respectively). According to study results, having a first-degree relative with a colorectal polyp correlated with a higher risk for CRC (OR = 1.4; 95% CI, 1.35-1.45). Further, there was a higher risk for CRC in patients with an increased number of first-degree relatives with colorectal polyps ( 2 relatives OR = 1.7; 95% CI, 1.52-1.9) as well as in patients with a decreased age at colorectal polyp diagnosis (< 50 years OR = 1.77; 95% CI, 1.57-1.99); researchers noted the strongest association between family history and CRC was early onset diagnoses before age 50 ( 2 relatives OR = 3.34; 95% CI, 2.05-5.43). Joint analysis yielded ORs of 1.79 (95% CI, 1.52-2.1), 1.7 (95% CI, 1.65-1.76) and 5 (95% CI, 3.77-6.63) for individuals with two or more first-degree relatives with colorectal polyps but no CRC, individuals with one first-degree relative with CRC but no colorectal polyps and individuals with two or more first-degree relatives with both, respectively.
“If additional studies reveal a link between a family history of polyps and the risk of colorectal cancer, it is something to take into account in the screening recommendations, especially for younger adults," Jonas F. Ludvigsson, MD, PhD, Orebro University Hospital and professor in the department of medical epidemiology and biostatistics at the Karolinska Institutet, said in a press release. "I really hope that this study can help doctors in Sweden and elsewhere identify patients at a higher risk of colorectal cancer."