Prognostic value of ADCtot for overall survival of patients with locally advanced pancreatic cancer receiving CyberKnife followed by sequential S-1 / 中华胰腺病杂志

ABSTRACT

Objective To explore the prognostic value of ADC tot of diffusion-weighted magnetic resonance imaging with multiple diffusion gradient factor ( b) values ( Mb DWI) in predicting overall survival (OS) of patients with locally advanced pancreatic cancer (LAPC) undergoing CyberKnife and sequential S-1. Methods Forty-one LAPC patients were enrolled (28 male and 13 female), who had routine pancreatic MRI and multiple b value DWI (Mb DWI, b value =0, 25, 50, 75, 100, 150, 200, 400, 600, 800 and 1000 s/mm2) scan (3.0 T) prior to radiotherapy.ADCtot value was calculated using single index model .Two independent radiologists on abdominal radiology manually drew the target area of interest and measured ADC tot at 1-month interval, and the interclass correlation coefficient (ICC) was calculated.The median ADCtot was used as a standard to divided the data into high value and low value .The survival was analyzed by Kaplan-Meier method and compared by log rank test .Cox proportional hazard model was employed to identify predictive factors for OS.Results The median ADCtot value by two independent radiologists was (1.54 ±0.27) ×10 -3 and(1.55 ±0.28) ×10 -3 mm2/s, respectively.The ICC was 0.994, and the consistency was good.Pre-treatment ADC tot value was the independent prognostic factor for the OS of patients who received CyberKnife and S-1 (HR 1.083, 95％CI 1.083-12.554,P=0.0368), indicating that the mortality increased by 1.083 times as ADCtot increased by 1 unit.Similarly, CyberKnife combined with S-1 was also the independent prognostic factor for the OS (HR0.329, 95％CI 0.142-0.765, P=0.0098), indicating that the mortality of patients treated by CyberKnife and S-1 was 0.329 times of that of patients who did not take S-1. Conclusions The pre-treatment ADC tot was an independent predictor for OS of LAPC patients treated by CyberKnife and sequential S-1, which had a certain prognostic value .