While colorectal cancer incidence and mortality rates have seen significant reductions since 2000 in older people, these numbers seem to be increasing in adults younger than 50, according to the most recent update of the American Cancer Society on colorectal cancer incidence, survival, and mortality rates.
Results suggest that race and tumor site also play a role in how outcomes unfold.
The findings were published in the latest issue of Colorectal Cancer Statistics, titled “Colorectal cancer statistics, 2017,” accompanied by the “Colorectal Cancer Facts & Figures” three-year review by the American Cancer Society.
According to a press release, colorectal cancer is the third most frequently diagnosed cancer in men and women in the United States. This year alone, 95,520 new cases of colon cancer are estimated to be diagnosed as well as 39,910 new cases of rectal cancer.
While men and women are equally affected by colon cancer, numbers show that men will be more affected by rectal cancer than women (23,720 vs. 16,190 new cases, respectively).
Native Alaskans were found to have the highest incidence rates of colorectal cancer (91 per 100,000 people), compared to African Americans (49 per 100,000 people), and Asian Americans and Pacific Islanders, who had the lowest rates (32 per 100,000 people).
Age differences were also significant for colorectal cancer rates. For people age 50 and older, the incidence dropped by 32 percent since 2000, but among those under age 50, the incidence rates increased by 22 percent between 2000 and 2013.
The trend in older people could be explained by the increased investment in screening, which detects and lead to the removal of suspicious polyps before cancer develops. In comparison, unhealthy lifestyles and dietary patterns in younger generations could explain why the incidence for this cancer is on the rise.
Rectal tumor incidence rates declined slightly (by 9 percent) among men ages 50 to 64. But no decline was seen among women in the same age group. In people older than 65, however, the incidence of rectal tumors dropped by 38 percent in men and 41 percent in women.
Location also seems to play a role in colorectal cancer incidence. While a decline was observed among people older than 50 in all states, only seven states saw a decline above 5 percent annually from 2009 to 2013. Of note, the slowest rates of decline were observed in the five states with the highest incidence of colorectal cancer.
According to the National Health Interview Survey (NHIS), screening rates increased in people ages 50 and above from 2013 to 2015 and from 65 percent to 68 percent in people older than 65. If screening rates remained this high, an estimated 39,700 colorectal cancer cases would be prevented through 2030.
The authors highlight that reducing inequalities and accelerating progress could be attained by ensuring equitable treatment for all patients, and by increasing initiation of screening at age 50 for those with a family history of colorectal cancer or advanced adenomas.