Early tumor shrinkage as a prognostic predictor in chemotherapy-naïve patients with locally advanced pancreatic cancer treated with modified FOLFIRINOX or gemcitabine plus nab-paclitaxel combination therapy: An exploratory analysis of JCOG1407.

ABSTRACT

BACKGROUND: Early tumor shrinkage (ETS) is a prognostic predictor for patients treated with chemotherapy in colorectal cancer, although scarce studies evaluated its potential in locally advanced pancreatic cancer (LAPC). In this exploratory analysis of JCOG1407, a randomized phase II study comparing modified 5-fluorouracil, levofolinate, irinotecan, and oxaliplatin (mFOLFIRINOX) and gemcitabine plus nab-paclitaxel (GnP), we evaluated whether ETS can predict prognosis of patients with LAPC. METHODS: Of the 126 patients enrolled in JCOG1407, 112 with measurable lesions were included in this study. ETS was defined as a ≥20 % reduction in tumor diameter compared with baseline at the initial imaging assessment 6-10 weeks after initiating chemotherapy. Patients were divided into the ETS (achieved ETS) and non-ETS (failed to achieve ETS) groups based on their ETS status. The impact of ETS on overall survival (OS) was compared using multivariable Cox regression analysis. RESULTS: Fourteen of 55 (25.5 %) and 24 of 57 (42.1 %) patients in the mFOLFIRINOX and GnP arms, respectively, achieved ETS. In the overall population, mFOLFIRINOX arm, and GnP arm, the median OS in the ETS and non-ETS groups was 27.1 and 20.4, 29.8 and 20.6, and 24.1 and 20.4, months, respectively. The adjusted hazard ratios of OS for the ETS group in the overall population, mFOLFIRINOX arm, and GnP arm were 0.451 (95 % confidence interval [CI] 0.270-0.754), 0.371 (95 % CI 0.149-0.926), and 0.508 (95 % CI 0.255-1.004), respectively. CONCLUSIONS: ETS may be a prognostic predictor in chemotherapy-naïve patients with LAPC treated with mFOLFIRINOX or GnP.