Prospective study evaluating Na18F PET/CT in predicting clinical outcomes and survival in advanced prostate cancer

Abstract

This prospective pilot study evaluated the ability of Na18F PET/CT to detect and monitor bone metastases over time and its correlation with clinical outcomes and survival in advanced prostate cancer. Methods: Sixty prostate cancer patients, including 30 with and 30 without known bone metastases by conventional imaging, underwent Na18F PET/CT at baseline, 6 mo, and 12 mo. Positive lesions were verified on follow-up scans. Changes in SUVs and lesion number were correlated with prostate-specific antigen change, clinical impression, and overall survival. Results: Significant associations included the following: SUV and prostate-specific antigen percentage change at 6 mo (P = 0.014) and 12 mo (P = 0.0005); SUV maximal percentage change from baseline and clinical impression at 6 mo (P = 0.0147) and 6-12 mo (P5 0.0053); SUV change at 6mo and overall survival (P = 0.018); number of lesions on Na18F PET/CT and clinical impression at baseline (P < 0.0001), 6 mo (P = 0.0078), and 12 mo (P = 0.0029); and number of lesions on Na18F PET/CT per patient at baseline and overall survival (P = 0.017). In an exploratory analysis, paired 99mTc-methylene diphosphonate bone scans (99mTc-BS) were available for 35 patients at baseline, 19 at 6 mo, and 14 at 12 mo (68 scans). Malignant lesions on Na18F PET/CT (n 5 57) were classified on 99mTc-BS as malignant 65% of the time, indeterminate 25% of the time, and negative 10% of the time. Additionally, 69% of paired scans showed more lesions on Na18F PET/CT than on 99mTc-BS. Conclusion: The baseline number of malignant lesions and changes in SUV on follow-up Na18F PET/CT significantly correlate with clinical impression and overall survival. Na18F PET/CT detects more bone metastases earlier than 99mTc-BS and enhances detection of new bone disease in high-risk patients.