The Strain Ratio as Obtained by Endoscopic Ultrasonography Elastography Correlates With the Stroma Proportion and the Prognosis of Local Pancreatic Cancer

Objective: The aim of this study was to investigate the association of the strain ratio (SR) with clinicopathologic features and the prognostic value of the SR in local pancreatic cancer. Background: The SR as obtained by endoscopic ultrasonography elastography is useful in the differential diagnosis of pancreatic diseases. However, its role in the prognostic prediction of pancreatic cancer remains unknown. Methods: A total of 78 resected pancreatic cancer patients and 93 locally advanced pancreatic cancer (LAPC) patients were enrolled in this study according to the inclusion criteria. Masson trichrome staining was used to evaluate the stromal proportion. Survival rates were calculated according to the Kaplan-Meier method and were compared using the log rank test. Multivariate analysis was performed with a Cox regression model. Results: The SR was positively associated with the stromal proportion of resected pancreatic cancer (R = 0.768, P < 0.001). High SR was more likely in males (P = 0.039) and was related to perineural invasion (P = 0.022). High SR predicted unfavorable overall survival (OS) relative to low SR (15.4 vs. 25.8 mo, P = 0.017). SR was confirmed as an independent prognostic factor for resected pancreatic cancer based on multivariate analysis (hazard ratio = 1.939, P = 0.020). For LAPC patients who received nab-paclitaxel and gemcitabine, high SR was associated with improved prognosis (OS: 14.9 vs. 11.6 mo, P = 0.045), but this positive association was not observed in patients treated with other gemcitabine-based regimens (OS: 10.7 vs. 12.4 mo, P = 0.478). Conclusions: A high SR as obtained by endoscopic ultrasonography elastography was associated with poor prognosis of resected pancreatic cancer but predicted improved survival for LAPC patients treated with the nab-paclitaxel and gemcitabine regimen.