Delta HU is a potential marker to predict chemotherapy response for unresectable pancreatic ductal adenocarcinoma

Background: FOLFIRINOX and gemcitabine plus albumin-bound paclitaxel (AG) regimens are recommended as first-line therapy for both locally advanced and metastatic pancreatic cancer. However, there were no specific markers to conduct personalized regimen choice. The research is to assess delta Housfield unit (delta HU), which is the difference in CT attenuation value (in HU) between enhanced and nonenhanced phase of region of interest, as a marker for predicting chemotherapy response of unresectable pancreatic cancer.

Methods: A total of 179 unresectable pancreatic cancer patients were enrolled in the study. Kaplan-Meier analysis and COX regression analysis were performed for progression-free survival (PFS) and overall survival. The differences of clinical characteristics were analyzed by χ ²test. Microvessel density (MVD) was calculated by immunochemistry staining of CD34.

Results: Delta HU was an independent risk factor for unresectable pancreatic cancer (P = 0.017, HR 0.672, 95%CI 0.485-0.930). Patients with higher delta HU were associated with better PFS (P = 0.004). For modified FOLFIRINOX (mFOLFIRINOX) group, delta HU was an independent risk factor (P = 0.045, HR 0.571), but not for AG group (P = 0.473, HR 0.855). Delta HU was correlated with stroma MVD (P = 0.000, R = 0.483), not with parenchyma MVD (P = 0.074, R = 0.199).

Conclusions: Delta HU was a marker predicting chemotherapy response for unresectable pancreatic cancer. Higher delta HU was associated with better survival for patients receiving mFOLFIRINOX rather than AG. The delta HU was positively correlated with stroma MVD, explaining the relationship between delta HU and prognosis.