Abstract A049: Differences in treatment discontinuation among colorectal cancer patients by rural and urban status and age of onset
Authors: Ilozumba Mmadili N. , Byrd Doratha A. , Lin Tengda , Gigic Biljana , Warby Christy A. , Li Christopher I. , Siegel Erin Erin , Toriola Adetunji Adetunji , Figueiredo Jane C. , Shibata David , Cohen Stacey A. , Onega Tracy , Ose Jennifer , Hardikar Sheetal , Ulrich Cornelia M 
Published: September 2024

Abstract
Purpose of the study: Disparities in colorectal cancer (CRC) mortality are evident in rural and younger populations. While rurality-associated disparities in cancer care and outcomes may be exacerbated by limited access to high-quality cancer care, early-onset CRC patients undergo more aggressive treatment regimens, experiencing more gastrointestinal and less hematologic toxicities compared to late onset CRC patients, which may lead to treatment discontinuation. However, the impact of rural and urban residence and the age of CRC onset on adjuvant treatment discontinuation in CRC patients has not been established. Methods: Study participants included n= 192 patients with definitively treated stages I-IV CRC in the ColoCare Study recruited from the Huntsman Cancer Institute (HCI), Salt Lake City, Utah. Multivariable logistic regression models were used to assess the independent associations of rurality and early-onset CRC (&lt;50 years old), respectively with adjuvant treatment discontinuation in CRC patients. All analyses were adjusted for sex, age, tumor stage and tumor site. Results: Our study participants comprised of 45% rural residents and 55% urban residents, 51% males and 49% females. Amongst rural residents, 28% had early-onset CRC while 72% had late-onset CRC; 20% attended high school while 6% had an advanced degree. Early vs late-onset CRC and rurality were not associated with adjuvant treatment discontinuation (OR = 0.66, 95% CI =0.35, 1.24, p- value = 0.20 and OR= 1.14, 95% CI =0.62, 2.08, p-value = 0.68, respectively). Conclusions: We observed that 34% of younger patients are less likely to discontinue treatment despite receiving more aggressive treatment, although this finding was not statistically significant. Additionally, rural patients successfully achieve their treatment goals at HCI with fewer patients having to discontinue their treatment. By implementing patient navigation and reducing travel times for rural patients, we found no differences in treatment completion rates between rural and urban patients at HCI. These results provide valuable insights into addressing rural-urban disparities in CRC treatment. Future studies with larger sample sizes are required to confirm these findings.
Citation Format: Mmadili N. Ilozumba, Doratha A. Byrd, Tengda Lin, Biljana Gigic, Christy A. Warby, Christopher I. Li, Erin Erin Siegel, Adetunji Adetunji Toriola, Jane C. Figueiredo, David Shibata, Stacey A. Cohen, Tracy Onega, Jennifer Ose, Sheetal Hardikar, Cornelia M Ulrich. Differences in treatment discontinuation among colorectal cancer patients by rural and urban status and age of onset [abstract]. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr A049.