Background: Current guidelines recommend treatment of early-stage pancreatic cancer with surgical resection and chemotherapy. Undertreatment can occur after resection when patients fail to receive adjuvant chemotherapy. Final pathologic results have the potential to bias providers to omit adjuvant chemotherapy, however, the association of surgical pathology and adjuvant chemotherapy is unknown.
Methods: Data from the National Cancer Database identified patients who underwent surgery for stage I or II pancreatic cancer. Chi-square tests and logistic regression were used to determine differences between patients receiving surgery followed by chemotherapy and those who had resection alone. Survival analysis of subgroups with favorable pathology (node-negative disease, tumor size ≤ 2 cm, well-differentiated histology) was performed by the Kaplan-Meier method and the Cox proportional hazards model.
Results: Of the 22,131 patients included in this study, 28% were considered undertreated (surgery alone). Favorable pathologic traits of negative lymph nodes, tumor 2 cm in size or smaller, and well-differentiated histology were associated with a 15-35% lower probability that adjuvant chemotherapy would be given than less favorable pathologic results (p < 0.001). Multivariable survival analysis showed significantly lower odds of mortality for patients who received resection and chemotherapy than for those who were undertreated among two subgroups: patients with node-negative disease (hazard ratio [HR] 0.774) and those with a tumor 2 cm in size or smaller (HR 0.771).
Conclusion: The patients who had early-stage pancreatic cancer with favorable pathology after pancreatectomy were less likely than those with unfavorable pathology to receive adjuvant chemotherapy. This omission had significant survival consequences for subgroups with node-negative disease and tumors 2 cm in size or smaller. Recognition of patients with favorable pathology as an undertreated group is required for efforts to be directed toward encouraging guideline-concordant care and to combat undertreatment of pancreatic cancer.