Therapy assessment of locally advanced pancreatic adenocarcinoma: Hopkins criteria and FDG-PET/CT quantitative parameters.

Objectives This study aims to evaluate the predictive value of Hopkins criteria and quantitative PET/CT parameters for therapy response assessment in patients with locally advanced pancreatic adenocarcinoma (LAPC).

Methods Forty-two patients (median age 66 years) with LAPC were retrospectively included. PET/CT performed at a median of 4.6 weeks following completion of chemotherapy ± radiotherapy to assess therapy response. PET was interpreted visually using a structured qualitative five-point scale (Hopkins criteria for therapy assessment) and was dichotomized to negative (score 1-3) and positive (score 4 and 5) result. Quantitative PET/CT parameters including SUVmax, SUVpeak, Tumor lesion glycolysis (TLG), and metabolic tumor volume (MTV) were also measured using gradient segmentation method. Univariate and multivariate Cox regression analysis was performed using death as an endpoint and Kaplan Meir curves were generated with median and optimum cut points.

Results All patients, except 7, were followed until death. The median survivals were 14.6 vs. 8.7 months in patients with negative vs. positive PET scan (p=0.04). Positive Hopkins criteria was associated with increased hazard of death within 1-year (HR=3.32, p=0.03). In quantitative analysis, SUVmax (cut point 3.62; HR=5, p=0.001), SUVpeak (cut point 2.69; HR=4.18, p=0.002), TLG (cut point 57.92g; HR=2.82, p=0.01), and MTV (cut point 37.41ml; HR=3.6, p=0.003) were significantly predict death within 1-year following the therapy assessment PET scan. In multivariate cox-regression analysis, the median SUVpeak 2.64 (HR=6.15, p=0.006), TLG 43.98g (HR=2.97, p=0.01), and MTV 24.69ml (HR=2.69, p=0.03) were significant predictors of overall survival even after adjustment for age, sex, race, and serum level of post-treatment CA19-9.

Conclusions PET-based structured qualitative therapy assessment (Hopkins Criteria) and volumetric parameters can predict survival outcomes of patients with LAPC.