We have useful screening tools, but we can’t apply them to all people. We don’t know who to screen at a younger age, because we don’t yet understand which younger people are at increased risk.— Samir Gupta, MD
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Samir Gupta, MD, Associate Professor of Medicine at the University of California San Diego, who has led trials of colorectal cancer screening, commented on this study for The ASCO Post.
Although there are approximately 138,000 new colorectal cancer diagnoses a year in the United States, only about 15,000 are among persons younger than 50 years. Still, Dr. Gupta pointed out, this is not a small number. In fact, the number of new cases almost equals that of esophageal cases and exceeds that of cervical cancer, he added.
The results of the study are concerning, but they do not yet indicate a need to screen all individuals younger than 50, revealed Dr. Gupta. “We have useful screening tools, but we can’t apply them to all people. We don’t know who to screen at a younger age, because we don’t yet understand which younger people are at increased risk,” Dr. Gupta commented.
Risk Linked to Genetics?
It is likely that some of the risk is associated with genetics, but clearly not all, noted Dr. Gupta. At Digestive Disease Week 2016, a study by Stoffel et al found that approximately one in five persons developing colorectal cancer before age 50 had a pathogenic germ-line mutation in a cancer predisposition gene.1 “It’s a substantial population, but it’s still less than 30%,” Dr. Gupta noted.
Dr. Stoffel’s study also showed variability in phenotypes associated with hereditary cancer syndromes, suggesting that use of multigene panels can increase the yield of clinical genetic testing for this cancer, he added.
Even an understanding of genetic predisposition, however, does not “get at the prevention issue,” continued Dr. Gupta. “It only explains those who have cancer already.” Dr. Gupta added it is time to move from describing the trend in younger-age onset to determining how to tackle this problem. ■
Disclosure: Dr. Gupta reported no potential conflicts of interest.
Reference
1. Stoffel EM, Koeppe E, Williams L, et al: Outcomes of germline genetic testing in individuals with young onset colorectal cancer. 2016 Digestive Disease Week. Abstract 779. Presented May 23, 2016.
