Improvements in Colorectal Cancer Incidence Not Experienced by Nonmetropolitan Women: A Population-Based Study From Utah.

PURPOSE: Little is known about disparities in colorectal cancer (CRC) incidence and mortality by community-level factors such as metropolitan status.

METHODS: This analysis utilized data from the Surveillance, Epidemiology, and End Results (SEER) program from Utah. We included patients diagnosed with CRC from 1991 to 2010. To determine whether associations existed between metropolitan/nonmetropolitan county of residence and CRC incidence, Poisson regression models were used. CRC mortality was assessed using multivariable Cox regression models.

FINDINGS: CRC incidence rates did not differ between metropolitan and nonmetropolitan counties by gender (males: 46.2 per 100,000 vs 45.1 per 100,000, P = .87; females: 34.4 per 100,000 vs 36.1 per 100,000, P = .70). However, CRC incidence between the years of 2006 and 2010 in nonmetropolitan counties was significantly higher in females (metropolitan: 30.4 vs nonmetropolitan: 37.0 per 100,000, P = .002). As compared to metropolitan counties, the incidence of unstaged CRC in nonmetropolitan counties was significantly higher in both males (1.7 vs 2.8 per 100,000, P = .003) and females (1.4 vs 1.6 per 100,000, P = .002). Among patients who were diagnosed between 2006 and 2010, metropolitan counties were found to have significantly increased survival among males and females, but nonmetropolitan counties showed increased survival only for males.

CONCLUSIONS: While we observed a decreasing incidence of CRC among men and women in Utah, this effect was not seen in women in nonmetropolitan areas nor among those with unstaged disease. Further studies should evaluate factors that may account for these differences. This analysis can inform interventions with a focus on women in nonmetropolitan areas.