Selection of Patients Benefited From PET CT Whole Body Protocol

Abstract

Purpose/Objectives: The purpose of this study is to evaluate the predictive capabilities of diffusion-weighted MRI (DWI) and those of F-FDG PET/CT for tumor progressions and survival rates in patients with non-small cell lung carcinoma (NSCLC) treated with stereotactic body radiation therapy (SBRT). Materials/Methods: This study included 15 patients with histologically confirmed stage I NSCLC who underwent pretreatment MRI and FFDG PET/CT and were treated with SBRT in our hospital between January 2010 and December 2010. The median age was 80 years old (range, 70 to 86 years). Eleven patients were male and 4 were female. T stages were distributed as follows: T1a in 4, T1b in 6, and T2a in 5 patients. According to the classification with recursive partitioning analysis (RPA) proposed by Matsuo et al. (Int J Radiat Oncol Biol Phys 2011), 7 patients were classified into class I, which includes female or T1a patients, and 8 patients were into class II, including male and T1bT2a patients. The RPA class I was proved to have better prognosis than class II. The SBRT dose and fractions were 48Gy/4fr for T1a-T1b, 56Gy/4fr for T2a, and 60Gy/8fr for the tumors close to the mediastinum regardless of their size. Apparent diffusion coefficient (ADC) value and maximum standardized uptake value (SUVmax) were measured at the target lesion. The ADC value, SUVmax, and RPA class were evaluated for the correlation with Local progression (LP), disease progression (DP), and overall survival (OS). The Kaplan-Meier method, the log-rank test, and the Cox proportional hazards model were used to evaluate these factors. Results: With a median follow-up period of 19.3 months, OS at 12 and 24 months were 93% and 52%, respectively. Cumulative incidence rates of LP and DP were 8% and 33% at 12 months, and 18% and 63 % at 24 months, respectively. The median pretreatment ADC was 1.04 × 10–3 mm/s (range 0.831.29); that of the SUVmax was 9.9 (range 1.6-30). When dividing the patients into two groups by an ADC value of 1.04 x 10–3 mm/s, a significant difference was observed in DP (p = 0.023), while no significant difference was observed in LP and OS. The group with lower ADC value had poor prognosis, and RPA class distribution was well balanced between the two groups. On the contrast, there was no significant difference in the groups divided by SUVmax of 9.9 in LP, DP and OS. In the multivariate analysis, ADC remained a borderline significant factor for DP (p = 0.063). Conclusions: Our preliminary data suggest pretreatment DWI with low ADC value may be a poor prognostic factor in NSCLC patients after SBRT.