Screening in Younger First-Degree Relatives of Patients with CRC

Rosemary Frei, MSc

November 2015, Vol 6, No 10 - Cancer Screening


A study from the Centers for Disease Control and Prevention documented an average 38% colorectal cancer (CRC) screening rate among people aged 40 to 49 years, and a 69.7% rate in those aged ?50 years with a first-degree relative with CRC (Tsai M-H, et al. Prev Chronic Dis. 2015;12:140533). An earlier analysis of National Health Interview Survey (NHIS) data from 2005 and 2010 showed that first-degree relatives of patients with CRC were 70% more likely to have a colonoscopy than their counterparts.

The American College of Gastroenterology guidelines call for CRC screening starting at age 40 years in all persons with a first-degree relative with CRC. However, the screening rates found in the new study are in line with the US Preventive Services Task Force recommendation of no screening before age 50 years in people at average risk, including those with first-degree relatives with sporadic CRC, except for those with first-degree relatives who had cancer at a younger age or those with >1 affected first-degree relative.

Sudha Xirasagar, PhD, MBBS, Associate Professor of Health Services Policy and Management, Arnold School of Public Health, University of South Carolina, Columbia, who led the study, noted that first-degree relatives are not average-risk individuals.

“They are a higher-than-average risk group, for whom prevention guidelines may be better assessed by the specialty groups that treat higher-risk subgroups,” Dr Xirasagar told Value-Based Cancer Care.

“The remedy to the contradiction is to pursue prospective studies of first-­degree relatives to finalize the optimum screening age, rather than remaining anchored to a position taken by an organization with a minimalist approach to preventive services that may serve the general population well but may endanger higher-risk subpopulations. In retrospect, our paper should have highlighted the contradiction,” Dr Xirasagar said.

Dr Xirasagar and her coinvestigators found 2470 individuals with a family history of CRC in the 2005 and 2010 NHIS data. In 2005, 25.2% of individuals with a family history of CRC underwent colonoscopy; this rate rose to 65.8% in 2010.

Among those aged 40 to 49 years with a family history, 12.7% had a colonoscopy in 2005 and 38.3% in 2010; the respective rates for those aged 50 to 64 years were 21.4% and 69.1%, and for those aged ?65 years, 32% and 70.3%.

The adjusted likelihood of colonoscopy was 1.7 in individuals with a family history of CRC compared with those without a family history. Furthermore, the adjusted likelihood of having a colonoscopy for individuals with private insurance was 3.3 and 3.4 for those with public insurance.