EP466 - Does Guideline-Concordant Therapy Explain Disparities in Outcomes among Rural and Urban Patients with Stage III Rectal Adenocarcinoma? A Nationwide Analysis

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Purpose/Background: Colorectal cancer is the fourth leading cause of new cancer diagnoses and second leading cause of cancer deaths in the United States, with an increased incidence and mortality from colorectal cancer observed in patients under age 50. The vast majority of epidemiologic studies in the field combine colon and rectal cancer outcomes because of their pathophysiological similarities, yet the treatment paradigms in rectal cancer differ significantly from that of colon cancer. Rectal cancer is unique to colon cancer in that it requires a greater degree of multidisciplinary treatment which includes specialty surgical care. Patients living in rural areas are more likely to be older, have more co-morbidities, and to be uninsured or underinsured. These factors may make access to the complex care for rectal cancer more difficult for patients in rural areas than for their urban counterparts.

Methods/Interventions: Patients diagnosed with single-site stage III rectal adenocarcinoma who underwent rectal surgery were identified from the 2010-2020 National Cancer Database (NCDB). Patients were stratified by whether they resided in a rural or urban area (defined by Rural-Urban Continuum Codes). The primary outcome was overall survival; time-to-death and risk of death were evaluated via Kaplan-Meier survival estimates and Cox proportional hazards models. Secondary outcomes were rate of treatment at an academic facility, surgical approach, margin status, receipt of neoadjuvant therapy, 30-day readmissions, 30 and 90-day mortality, post-surgery length of stay, distance to treating facility, and time from diagnosis to treatment. Secondary outcomes were assessed via logistic regression or log-normal models. Adjusted models controlled for patient age, sex, insurance, and comorbidity burden.

Results/Outcomes: Overall survival was distinct between rural and urban patients; rural patients had 13% greater adjusted risk of death compared to urban patients (95% CI: 1.07-1.20, p< 0.001; Figure 1). Irrespective of receiving neoadjuvant therapy, rural patients had worse survival outcomes compared to urban patients; rural patients who received neoadjuvant therapy had 15% greater adjusted risk of death (95% CI: 1.08-1.22, p < 0.001) and rural patients who did not receive neoadjuvant therapy had 19% greater adjusted risk of death (95% CI: 1.00-1.41, p < 0.047). Notably, rural patients had 20% lower adjusted odds of receiving treatment at an academic or research facility (95% CI: 0.75-0.85, p< 0.001), 14% greater adjusted odds of 30-day unplanned readmission (95% CI: 1.01-1.30, p = 0.040), 9% longer stays following surgery (95% CI: 1.01-1.17, p=0.021), 4.32 times longer distance to travel to a facility (95% CI: 4.17-4.48, p< 0.001), and 7% longer time to initial treatment (95% CI: 1.01-1.13, p = 0.016). Results for secondary outcomes are presented in Table 1.

Conclusion/Discussion: Patients residing in rural areas who received surgical treatment of stage III rectal adenocarcinoma had worse adjusted overall survival than their urban counterparts. This trend persisted whether any neoadjuvant treatment was given and the type of treatment provided. While rural patients were less likely to receive care at an academic center and had to travel over 4 times further to receive treatment, they had similar time to initial treatment and surgery. Rurally based patients likewise received guideline concordant neoadjuvant therapy and underwent minimally invasive surgery with negative margins at the same rate as those in urban areas.