Spotlight on National CRC Awareness Month

March is National Colorectal Cancer (CRC) Awareness Month, and recent studies reported trends in CRC incidence and mortality and compared time to diagnosis and treatment between younger and older adults.

In the first study, published on March 1 by CA: A Cancer Journal for Clinicians, the American Cancer Society provided updated statistics on CRC, the second most common cause of cancer death in the U.S., based on incidence from population-based cancer registries and mortality from the National Center for Health Statistics. The organization provides such an update every three years.

In 2023, about 153,020 individuals will be diagnosed with CRC and 52,550 will die of the disease, including 19,550 cases and 3,750 deaths in individuals younger than age 50 years, the researchers estimated. The decline in CRC incidence slowed from 3% to 4% each year during the 2000s to 1% annually during 2011 to 2019, driven partly by a 1% to 2% annual increase in individuals younger than age 55 years since the mid-1990s. The proportion of cases in this younger population increased from 11% in 1995 to 20% in 2019. There was a shift to later-stage diagnosis in recent years: 60% of all new cases were advanced in 2019 versus 52% in the mid-2000s and 57% in 1995, before widespread screening. There was also a shift to left-sided tumors. “Although overall CRC mortality continues to decline, this progress is tempered by a rapidly changing landscape of disease that foreshadows less favorable trends ahead,” including shifts to diagnosis at a younger age, at a more advanced stage, and in the left colon/rectum, the researchers concluded.

The second study found that while adults younger than age 50 years presented more often with stage IV CRC, they had overall similar times from presentation to treatment as screening-eligible older adults. Researchers conducted a population-based study of adults diagnosed with CRC in Ontario, Canada, from 2003 to 2018. They measured time between presentation and diagnosis (diagnostic interval), time between diagnosis and treatment start (treatment interval), and time from presentation to treatment (overall interval) and compared interval lengths between adults younger than age 50 years, ages 50 to 74 years, and ages 75 to 89 years. Results were published online on Feb. 23 by Gastroenterology.

The study included 90,225 patients with CRC, 6,853 (7.6%) who were younger than age 50 years. Compared to middle-aged patients, younger patients were more likely to be female, present emergently, have stage IV disease, and have rectal cancer. Factors associated with significantly longer overall intervals included female versus male sex (8.7 days; 95% CI, 6.6 to 10.9 days) and rectal cancer versus proximal colon cancer (9.8 days; 95% CI, 7.4 to 12.2 days). In adjusted analyses, younger adults had significantly longer diagnostic intervals (4.3 days; 95% CI, 1.3 to 7.3 days) and significantly shorter treatment intervals (−4.5 days; 95% CI, −5.3 to −3.7 days) compared with middle-aged patients; however, there was no significant difference in the overall interval (−0.6 day; 95% CI, −4.3 to 3.2 days). In stratified models, younger adults with stage IV disease who presented emergently and patients older than age 75 years had longer overall intervals. The study was limited by the possibility of misclassification and by the need to measure intervals that began with some degree of interaction with the health care system, the authors noted.