Hypoxic condition monitoring and treatment evaluation for non-small cell lung cancer before and after radiotherapy by 18F-FMISO PET/CT

Abstract

Objective To evaluate the changes of hypoxic conditions in non-small cell lung cancer (NSCLC) patients before and after radiotherapy and assess the value of 18F-fluoromisonidzaole (FMISO) PET/CT for radiotherapy efficacy evaluation. Methods A total of 21 NSCLC patients (15 males, 6 females, age 30-74 years) from January 2014 to October 2016 were prospectively enrolled. 18F-FMISO PET/CT was performed before and after radiotherapy, and all patients underwent 18F-fluorodeoxyglucose (FDG) PET/CT before radiotherapy. Routine chest CT was performed at the 3rd and 6th month after radiotherapy. The maximum standardized uptake value (SUVmax) of tumor and muscle, tumor volume and hypoxic volume (HV) were measured. Tumor-to-muscle (T/M) value of 18F-FMISO was calculated, and T/M ≥1.3 was considered as the hypoxia cut-off value. Data were analyzed using Pearson correlation, paired t test, signed rank sum test and Wilcoxon rank sum test. Results Totally 81.0%(17/21) of NSCLC patients had hypoxia. There were significant positive correlations between 18F-FMISO T/M value and tumor volume or 18F-FDG SUVmax (r: 0.72, 0.60, both P<0.05). The T/M value after radiotherapy was significantly lower than that before radiotherapy (1.42±1.12 vs 2.08±0.71; t=3.62, P<0.05), and median HV was also significantly lower than that before radiotherapy (6.53 vs 12.41 cm3;z=-3.83, P<0.05). The median T/M values of effective group (n=14) and ineffective group (n=7) before radiotherapy were significantly different (2.14 vs 2.87; z=-2.27, P<0.05), and the median HV of 2 groups before radiotherapy was also significantly different (6.43 vs 10.20 cm3;z=-2.14, P<0.05). Conclusions Most NSCLC patients have hypoxia before radiotherapy. The larger tumor volume, the higher degree of hypoxia. Radiotherapy can alleviate the hypoxia of tumors. 18F-FMISO PET/CT imaging before radiotherapy can be used to predict the efficacy of patients with NSCLC. Key words: Carcinoma, non-small lung; Radiotherapy; Cell hypoxia; Positron-emission tomography; Tomography, X-ray computed; Nitroimidazoles