Understaging of clinical stage I pancreatic cancer and the impact of multimodality therapy.

Background: Although current guidelines recommend multimodal therapy for all patients with pancreatic ductal adenocarcinoma, it is unclear the extent to which clinical stage I patients are accurately staged and how this may affect management.

Methods: In this retrospective cohort study of 4,404 patients aged 18-79 years with clinical stage 1 (ie, T1N0 or T2N0) pancreatic ductal adenocarcinoma treated with upfront resection in the National Cancer Database (2004-2014), understaging was ascertained by comparing pretreatment clinical stage with pathologic stage. The association between adjuvant treatment and overall risk of death among true stage I and understaged patients was evaluated using multivariable Cox regression.

Results: Upstaging was identified in 72.6% of patients (62.8% T3/4, 53.9% N1) of whom 69.7% received adjuvant therapy compared with 47.0% with true stage I disease. Overall survival at 5 years among those with true stage I disease was significantly higher than those who had been clinically understaged (42.9% vs 16.6%; log-rank, p < 0.001). For true stage I patients, adjuvant therapy was not associated with risk of death (hazard ratio: 1.07, 95% confidence interval: 0.89-1.29). For understaged patients, adjuvant therapy significantly decreased risk of death (hazard ratio: 0.64, 95% confidence interval: 0.55-0.74).

Conclusion: The majority of clinical stage I pancreatic ductal adenocarcinoma patients actually have higher-stage disease and benefit from multimodal therapy; however, one third of understaged patients do not receive any adjuvant treatment. Clinicians should discuss all potential treatment strategies with patients (in the context of the acknowledged risks and benefits), including the utilization of neoadjuvant approaches in those presenting with potentially resectable disease.