EP850 - Factors Associated with Long-Term Overall Survival in Surgically Treated Rectal Cancer

Purpose/Background: Rectal cancer accounts for one-third of colorectal cancer cases in the United States, and survival remains highly variable. This study aims to determine stage specific overall survival in surgically treated rectal cancer by analyzing demographic, socioeconomic, tumor, and treatment-related factors.

Methods/Interventions: We performed a retrospective analysis of patients surgically treated for rectal cancer using the National Cancer Database (2004-2020). AJCC stage information was standardized into stages I-IV. Survival was grouped as 0-2, 2-5, or >5 years from diagnosis to last contact or death, without censoring. Ordinal logistic regression estimated adjusted odds ratios (aORs), reflecting the likelihood of belonging to a higher survival category after accounting for demographic, socioeconomic, tumor, and treatment characteristics.

Results/Outcomes: Of 142,532 patients, 31.8% had stage I, 27.7% II, 32.0% III, and 8.5% IV. Across stages I–IV, older age consistently correlated with a lower likelihood of >5-year survival (aOR 0.97–0.98, 95% CI 0.96–0.98).

Medicaid coverage or lack of insurance was associated with decreased odds of long-term survival across stages. The non-Hispanic Black population demonstrated worse survival in Stage I (aOR 0.75, 95% CI 0.56–0.99) and III (aOR 0.86, 95% CI 0.75–0.99). Hispanic/Other race also had lower odds in Stage I (aOR 0.68, 95% CI 0.49–0.95) and III (aOR 0.80, 95% CI 0.68–0.94). Higher comorbidity burden predicted worse outcomes in Stage I (aOR 0.89, 95% CI 0.80–0.99), II (aOR 0.83, 95% CI 0.78–0.89), III (aOR 0.89, 95% CI 0.84–0.94), and IV (aOR 0.88, 95% CI 0.78–1.00).

Well or moderately differentiated histology was associated with improved >5-year survival in Stage II (aOR 1.49–1.62, 95% CI 1.02–2.30), III (aOR 1.51–1.57, 95% CI 1.19–2.09), and IV (aOR 2.55–2.62, 95% CI 1.40–4.45). Non-adenocarcinoma histology was associated with worse survival in Stage III (aOR 0.64, 95% CI 0.42–0.98) and IV (aOR 0.44, 95% CI 0.23–0.87). Lack of lymphovascular invasion was protective in Stage I (aOR 1.24, 95% CI 1.05–1.47), II (aOR 1.73, 95% CI 1.53–1.94), III (aOR 1.63, 95% CI 1.49–1.79), and IV (aOR 1.44, 95% CI 1.23–1.68).

Achieving negative surgical margins was among the strongest predictors of >5-year survival across all stages (Stage I aOR 3.64, 95% CI 1.02–13.0; II aOR 1.97, 95% CI 1.68–2.31; III aOR 3.33–4.77, 95% CI 1.90–11.17; IV aOR 2.17, 95% CI 1.17–4.02). Treatment at academic centers was associated with improved survival in Stage III (aOR 1.16, 95% CI 1.05–1.29). Postoperative chemoradiation also conferred a survival advantage in Stage I (aOR 1.40, 95% CI 1.06–1.86), III (aOR 1.31–1.33, 95% CI 1.07–1.58), and IV (aOR 1.27, 95% CI 1.06–1.51). Patients from rural areas demonstrated improved outcomes in Stage IV (aOR 1.75, 95% CI 1.04–2.94).

Conclusion/Discussion: Rectal cancer survival reflects the combined influence of treatment quality and socioeconomic factors, with persistent disparities by insurance status, race, and comorbidity burden. Although tumor markets and characteristics are strong prognostic markers, there are modifiable disparities we can target with timely treatment and achieving negative surgical margins to improve overall survival.