Type of neoadjuvant treatment strategy is associated with differential pathologic responses in pancreatic ductal adenocarcinoma

Abstract

BackgroundTumor fibrosis after neoadjuvant treatment (NAT) for pancreatic ductal adenocarcinoma (PDAC) correlates with treatment response. Herein we assessed how different NAT strategies influence pathologic responses and survival. MethodsPatients with surgically resected PDAC who received NAT (1991–2020) were included. Descriptive statistics compared outcomes amongst fibrosis groups (none, minor <50 ​%, partial 51%–94 ​%, major ≥95 ​%) and NAT (chemotherapy alone, chemoradiation, or chemotherapy ​+ ​chemoradiation (total neoadjuvant therapy, TNT)). ResultsPatients with major fibrosis most often received TNT (65.8 ​%, p ​< ​0.001). Major fibrosis was associated with the greatest rate of downstaging (77.8 ​%, p ​< ​0.001), highest R0 margin rate (100 ​%, p ​< ​0.01), and lowest mean positive lymph node ratio (0.80, p ​< ​0.01). Amongst complete responders, 11/14 (78.6 ​%) received TNT. Median overall (66.3 months, p ​= ​0.003) and disease-free (54.7months, p ​= ​0.05) survival were highest with major fibrosis. ConclusionsMajor fibrosis and complete pathologic responses after NAT are most frequent with a TNT strategy and are associated with improved outcomes.