The recent upswing in rates of young-onset colorectal cancer has mostly been due to an increase in rectal cancer, particularly among white patients, according to research published in Gastroenterology.
Caitlin C. Murphy, PhD, MPH, of the division of epidemiology at the University of Texas Southwestern Medical Center, and colleagues wrote that there has been plenty of research on increasing rates of young-onset CRC, but it has revealed little insight about racial disparities for the disease.
“Rates of colorectal cancer have increased in younger adults, but we know little about reasons for this increase,” she told Healio Gastroenterology and Liver Disease.
Investigators compared CRC incidence and relative survival among younger patients (younger than 50 years) using data from the Surveillance, Epidemiology, and End Results program of cancer registries. They assessed rates between 1992 and 2014, in two different periods (1992–1996 and 2010–2014) and races (white and black).
Researchers found that CRC incidence increased from 7.5 per 100,00 patients in 1992-1996 to 11 per 100,000 patients in white individuals, while the rate increased from 11.7 to 12.7 per 100,000 patients among black individuals. The increased rates of rectal cancer were larger among whites (2.7 to 4.5 per 100,00 patients) compared with black patients (3.4 per 100,000).
Regarding survival, researchers found that black patients had a smaller increase in relative survival with proximal colon cancer but larger increases in survival with rectal cancer (55.3% to 70.8%). Both groups had similar survival rates for rectal cancer.
Murphy said more answers are needed to get the full picture of the increase in CRC rates among younger adults.
“Our study shows increasing rates are driven by higher rates of rectal cancer among whites. By comparison, there were much smaller increases in colon cancer and among blacks,” Murphy said. “Understanding the different causes of rectal vs. colon cancer will help identify reasons why rates have increased in younger adults.” – by Alex Young
Disclosures: The authors report no relevant financial disclosures.