A National Evaluation of Adjuvant Chemotherapy in pT4N0M0 Colon Cancer from the National Cancer Database
Thais Reif de Paula, Deborah S Keller- Cancer Research
- Oncology
Abstract
Background
T stage is a prognostic biomarker for overall survival (OS) in colon cancer and pathologic T4 (pT4) disease is a high-risk characteristic. Adjuvant chemotherapy (AC) is recommended to improve OS in pT4N0M0, but compliance with guidelines is unknown. We aimed to evaluate AC use and impact on OS in pT4N0M0 colon cancer.
Methods
The NCDB was reviewed for pT4N0M0 colon adenocarcinomas undergoing curative surgical resection(2010–2017). Cases were stratified into no AC and AC cohorts. Moderated multiple regression assessed factors associated no. Kaplan Meier and Cox regression assessed OS in propensity-score matched cohorts. The main outcome measures were AC use, factors associated with AC and impact on OS.
Results
Of 11,847 cases, 62.4%(n = 7,391) received no AC. With private insurance, comorbidities or income do not affect AC use. Medicare CCI0 (OR 0.861[95%CI 0.760–0.975];p=0.019) and Medicare payors with high-income (OR 0.813[95%CI 0.690–0.959];p=0.014) were associated with AC. Medicaid CCI0 (OR 1.374[95%CI 1.125–1.679]; p = 0.002) and uninsured CCI0 (OR 1.351[95%CI 1.120–1.629]; p = 0.002] were associated with no AC. AC was associated with improved 5-year OS [71.7% versus 56.4%;p<0.001; adjusted HR 0.543[95%CI 0.499–0.590];p<0.001).
Conclusion
While AC is associated with improved OS, compliance is low. There is a complex relationship between payor, income, comorbidity, and AC receipt. Medicare patients with no comorbidities or higher income have better AC use. With private insurance, AC compliance is not affected by comorbidities or income, while Medicaid and uninsured patients with no comorbidities have poor compliance. Future work could target these disparities for equitable care.