Young Relatives of Late-Onset Colon Cancer Patients Also at Higher Risk
October 13th, 2016
SALT LAKE CITY, UT – Recommended screening of first-degree family members of patients with colorectal cancer might not be broad enough, according to a new study finding that the age of onset could be less important than current guidelines suggest.
The study, published online recently by Clinical Gastroenterology and Hepatology, finds that all relatives of colorectal cancer patients are at increased risk for the cancer, regardless of the index patient’s age at diagnosis.
University of Utah researchers suggest their discovery could affect future guidelines regarding colorectal cancer screening.
"Most surprising, we identified a more than two-fold increase in risk of colorectal cancer among young first-degree relatives (under 50 years of age) of individuals diagnosed with colorectal cancer at advanced ages (60 to 80 years)," explained lead study author N. Jewel Samadder, MSc, MD, from Huntsman Cancer Institute at the University of Utah.
"This risk is not currently appreciated,” Samadder said in an American Gastroenterological Association press release. “Increased awareness of this risk may serve as incentive to increase screening intensity for all patients with a first-degree family history of colorectal cancer.”
For the population-based case-control study, the researchers used the Utah Cancer Registry to identify 18,208 index patients diagnosed with colorectal cancer between 1980 and 2010; age- and sex-matched cancer-free individuals were selected to create the comparison group.
Increased risk was observed in all relatives regardless of age of the family member's cancer diagnosis, although the risk was greatest for young relatives (under 50 years) of individuals who were diagnosed with colorectal cancer before 40. Yet, results indicate, familial risk was increased in first-degree relatives even when the index case was diagnosed with cancer at an advanced age older than 80.
“All relatives of individuals with CRC are at increased risk for this cancer, regardless of the age of diagnosis of the index patient,” study authors conclude. “Although risk is greatest among young relatives of early-onset CRC cases, relatives of patients diagnosed at advanced ages also have an increased risk.”
The researchers suggest their findings support current guidelines, which call for more aggressive screening for first-degree relatives of persons with colorectal cancer at an age younger than 60. The point out, however, that, colorectal cancer diagnosis even in an older patient can be a predictor of higher risk of the cancer in their relatives, and that family members might benefit from knowing the moderate risk and avoid known modifiable risk factors.