Changes in US colorectal cancer mortality trends over the past 20 years.

e15543 Background: In the last two decades, colorectal cancer (CRC) mortality has been decreasing in the United States (US). However, the mortality trends for the different subtypes of CRC, including different sides of colon, rectosigmoid, and rectal cancer remain unclear. Methods: We analyzed death certificate data from CDC WONDER from 1999 to 2020. We calculated age-adjusted mortality rates (AAMR) per 100,000 individuals of CRC and its different subtypes and examined the trends over time by estimating the average annual percent change (AAPC) using the Joinpoint Regression Program. Results: From 1999 to 2020, 1,166,099 deaths were attributed to CRC, of which 957,182 deaths (82.08%) were due to colon cancer, 148,862 deaths (12.77%) from rectal cancer, and 60,055 deaths (5.15%) from rectosigmoid cancer. The overall CRC rates decreased significantly from 26.42 (95% CI, 26.20-26.64) to 15.98 (95% CI, 15.84-16.12) per 100,000 individuals, with AAPC of -2.41 (95% CI, -2.55, -2.27). However, the AAMR of rectosigmoid cancer increased significantly from 0.82 (95% CI, 0.78 -0.86) to 1.08 (95% CI, 1.04-1.11) per 100,000 individuals and the AAMR of right-sided colon cancer increased from 0.57 (95% CI, 0.54-0.60) to 0.70 (95% CI, 0.67-0.73) per 100,000 individuals, with AAPC of +1.10 (95%, 0.21-2.00) and +2.06 (95% CI, 0.85 - 3.27) respectively. Men had higher AAMR of CRC than women (23.90 95% CI, 23.84-23.96 vs. 17.03 95% CI, 16.99-17.08 per 100,000 individuals). African Americans had the highest AAMR of CRC (26.93 95% CI, 26.79-27.07), followed by Whites (19.60 95%, 19.56-19.64 per 100,000 individuals), American Indians (14.53 95%, 14.15-14.92 per 100,000 individuals), and Asians (13.04 95%, 12.89-13.19 per 100,000 individuals). The overall AAMR of CRC decreased for those aged ≥ 50 years but increased significantly from 1.02 to 1.58 per 100,000 individuals for those aged 15-49 years, with an AAPC of +0.75. The AAMR from CRC was the highest in the Midwest (21.04 95% CI, 20.96-21.12 per 100,000 individuals), followed by the South (20.51 95% CI, 20.44-20.57), the Northeast (20.30 95% CI, 20.22-20.38 per 100,000 individuals), and the West (18.03 95% CI, 17.95-18.10 per 100,000 individuals). Rural populations had higher AAMR than urban populations (22.40 95% CI, 22.30-22.49 vs. 19.60 95%, 19.56-19.64 per 100,000 individuals). Conclusions: Although overall CRC mortality declined, there were rising trends in young-onset CRC, rectosigmoid cancer, and right-sided colon cancer. Disparities persist in terms of sex, race, geographic region, and urbanization level, emphasizing the need for targeted public health measures.