Is early-stage pancreatic adenocarcinoma truly early: stage migration on final pathology with surgery-first versus neoadjuvant therapy sequencing.

Background: Neoadjuvant therapy (NT) remains controversial in early-stage pancreatic ductal adenocarcinoma (PDAC), defined as clinical (c)Stage I-II. Our aim was to analyze rates of pathologic upstaging/downstaging for resectable PDAC treated with surgery-first (SF) vs. NT.

Methods: Utilizing the National Cancer Data Base (NCDB), patients with cStage I-II PDAC who underwent pancreatoduodenectomy in 2006-2013 were pathologically staged using the AJCC 8th edition and compared by treatment sequencing.

Results: Among 13,871 patients, 15.3% received NT. Despite higher pre-treatment T-stage (cT2: 71.9% vs. 56.3%, p < 0.001), NT patients had lower rates of pathologic nodal metastases (46.2% vs. 69.2% in SF, p < 0.001), suggesting higher rates of pathologic downstaging. In cStage II, 33.0% were upstaged to stage III after SF, vs. only 14.0% after NT. In cStage I, 65.5% were upstaged following SF, vs. 46.7% after NT (all p < 0.001). Patients with NT (HR-0.77, p < 0.001) or downstaging (HR-0.80, p < 0.001) had improved overall survival (OS).

Conclusion: NT is associated with reduction in unexpected upstaging, reduction in nodal positivity, and improved OS, compared to SF approach in putatively early-stage PDAC. Because clinical staging underestimates the underlying disease burden in resectable PDAC, patients with cStage I-II should be considered for NT.