Screening based on family history boosts detection of early-onset colorectal cancer

Last Updated: 2020-04-21

By Will Boggs MD

NEW YORK (Reuters Health) - Family history is a key component of identifying individuals at risk for early-onset colorectal cancer (CRC), researchers report.

"Consistently taking and acting on family cancer histories has great potential to improve early detection and prevention of early-onset colorectal cancer," Dr. Samir Gupta of San Diego Veterans Affairs Healthcare System and the University of California, San Diego, told Reuters Health by email.

Several national organizations, including the American Cancer Society (ACS), recommend initiating CRC screening at age 40 years or 10 years prior to the age of the youngest first-degree relative diagnosed with CRC for individuals with at least one first-degree relative or at least two second-degree relatives with CRC. Data supporting the effectiveness of this approach are limited.

Dr. Gupta and colleagues used data from the multisite Colon Cancer Family Registry to assess the performance of family history-based practice guidelines for identifying individuals with early-onset CRC. Their study included 2,473 CRC cases and 772 controls aged 40 to 49 years.

Family history-based criteria used in the joint ACS/US Multi-Society Task Force on CRC/American College of Radiology recommendation demonstrated 25% sensitivity and 90% specificity for identifying individuals with CRC diagnosed between ages 40 and 49 years, the team reports in Cancer.

Among the 614 individuals with CRC who were diagnosed in this age group and who met early-screening criteria, 604 (98.4%) could have been recommended screening initiation at an age younger than the observed age of diagnosis if family history-based criteria had been fully implemented.

"I thought it was very interesting to note that 98% of individuals who met criteria for early initiation of screening could have had screening initiation before their age of actual cancer diagnosis," Dr. Gupta said. "This means that they may have had the potential to have their cancers detected earlier (or even prevented) if family history-based guidelines had been applied."

Overall, 149 individuals with CRC (24%) had a first-degree relative present with CRC at an age younger than their own age at diagnosis, suggesting that earlier screening could have been recommended based on family history.

The mean age that would have been recommended based on guidelines for screening among CRC cases was nine years younger than the observed age of diagnosis, and 62.2% of CRC cases (382/614) could have been recommended screening initiation even before age 40 years.

The observed age at CRC diagnosis was the same as that of the youngest affected first-degree relative for about 44% of cases.

"Prior research suggests that patients often do not know their cancer family histories and that providers often do not ask about family history," Dr. Gupta said. "Even when family history is recorded, prior research has suggested that details are often missing. Overall, there is a lack of awareness of the importance of collecting family cancer history and of family history-based guidelines for cancer screening and prevention."

His advice to patients: "Know your cancer family history. Tell your doctor; it could be lifesaving for you or one of your family members."

"More work needs to be done to identify additional, complimentary strategies for identification of individuals who could benefit from early initiation of colorectal cancer screening," Dr. Gupta said.

Dr. Philip Schoenfeld of John D. Dingell VA Medical Center, in Detroit, and the University of Michigan School of Medicine, in Ann Arbor, who recently reviewed the evidence for screening individuals with a family history of colorectal cancer, told Reuters Health by email, "Physicians must be diligent about obtaining a family history from their patients, especially in primary-care settings, and initiate screening at the appropriate age. If this is done, then the vast majority of early-onset CRC would be prevented."

"Virtually all of the benefit occurred in individuals whose first-degree relative developed CRC before age 60," added Dr. Schoenfeld, who was not involved in the new study. "If your first-degree relative developed CRC >60 years of age, then the benefit of starting screening at age 40 is virtually the same as individuals who do not have a family history of CRC."

SOURCE: https://bit.ly/2XR1fqI Cancer, online April 20, 2020.