An analysis of nearly 29,000 U.S. women with early-onset colorectal cancer (CRC) showed that physical inactivity and fertility correlated modestly with living in “hot spots,” or counties with high early-onset CRC mortality rates among women.
Approximately one-third of the variation in early-onset CRC survival among women was accounted for by differences in individual- or community-level features.
Andreana N. Holowatyj, PhD, of Vanderbilt University Medical Center in Nashville, Tenn., and colleagues reported these findings in Clinical and Translational Gastroenterology.
Dr. Holowatyj and colleagues noted that prior studies have linked health behaviors with an increased risk of early-onset CRC among women. However, the impact of health behaviors on outcomes of early-onset CRC is unknown.
The researchers hypothesized that biological-, individual-, and community-level factors may be contributing to known sex-specific differences in CRC outcomes and geographic variations in survival by sex.
Hot spot counties with high mortality
The researchers identified geographic hot spots using three geospatial autocorrelation approaches with Centers for Disease Control and Prevention national
mortality data. The team also analyzed data from the Surveillance, Epidemiology, and End Results program on 28,790 women (aged 15-49 years) diagnosed with CRC during 1999-2016.
Of the 3,108 counties in the contiguous United States, 191 were identified as hot spots. Among these, 101 (52.9%) were located in the South.
Earlier research had shown a predominance of hot spots for early-onset CRC mortality among both men and women in the South.
However, the current study of women showed that almost half of these counties were located in the Midwest and the Northeast as well as the South.
Also in the current analysis, about one in every seven women (13.7%) with early-onset CRC resided in hot spot counties.
Race/ethnicity, stage at diagnosis, histopathology, and receipt of first-course therapies also differed significantly (P ≤ .0001) between women residing in hot spot versus non–hot spot counties.
Non-Hispanic Black patients, for example, accounted for 23.7% of early-onset CRC cases in hot spot counties, as compared with 14.3% in non–hot spot counties (P < .0001). The county-level proportion of non-Hispanic Black patients also modestly correlated with hot spot residence (rs = .26; P < .0001).
Race and ethnicity accounted for less than 0.5% of the variation in early-onset CRC survival among women in non–hot spot counties. In hot spot counties, however, this factor explained 1.4% of the variation in early-onset CRC-specific survival among women.
Inactivity correlates with hot spot residence
Dr. Holowatyj and colleagues also identified physical inactivity and lower fertility as county-level factors modestly correlated with hot spot residence (rs = .21, rs = –.23: P < .01).
Nearly a quarter of adults living in hot spot counties reported no physical activity during their leisure time (24.1% vs. 21.7% in non–hot spot counties; P < .01).
The rate of live births in the last year among women aged 15-50 years was lower in hot spot counties than in non–hot spot counties (4.9% vs. 5.4%; P < .01).
Individual- and community-level features overall accounted for different proportions of variance in early-onset CRC survival among women residing in hot spot counties (33.8%) versus non–hot spot counties (34.1%).
In addition to race and ethnicity, age at diagnosis, tumor histology, county-level proportions of the non-Hispanic Black population, women with a live birth in the last year, and annual household income of less than $20,000 all explained greater variance in CRC survival in young women in hot spot counties versus non–hot spot counties.
Keep CRC in differential diagnosis
“These individual- and community-level feature differences between hot spot and non–hot spot counties illustrate the importance of understanding how these factors may be contributing to early-onset CRC mortality among women – particularly in hot spot counties,” Dr. Holowatyj said in an interview. “They may provide us with key clues for developing effective strategies to reduce the burden of CRC in young women across the United States.
“Every primary care physician and gastroenterologist, particularly in hot spot counties, should keep CRC in their differential diagnosis, particularly if a patient is presenting with typical signs and symptoms, even if they are not yet of screening age. Early-stage diagnosis increases survival odds because the cancer may be easier to treat.”
Health professionals can also encourage physical activity and a healthy lifestyle, she added.
The authors declared no competing interests. Their research was funded by grants from the federal government and foundations.
SOURCE: Holowatyj AN et al. Clin and Transl Gastroenterol. 2020;11:e00266.