Prognostic value of baseline [¹⁸F] fluorodeoxyglucose positron emission tomography and^99mTc-MDP bone scan in progressing metastatic prostate cancer

Purpose: To compare the diagnostic and prognostic value of [¹⁸F] fluorodeoxyglucose positron emission tomography (FDG-PET) and bone scans (BS) in the assessment of osseous lesions in patients with progressing prostate cancer. Experimental Design: In a prospective imaging trial, 43 patients underwent FDG-PET and BS prior to experimental therapies. Bone scan index (BSI) and standardized uptake value (SUV) on FDG-PET were recorded. Patients were followed until death (n = 36) or at least 5 years (n = 7). Imaging findings were correlated with survival. Results: Osseous lesions were detected in 39 patients on BS and 32 on FDG-PET (P = 0.01). Follow-up was available for 105 FDG-positive lesions, and 84 (80%) became positive on subsequent BS. Prognosis correlated inversely with SUV (median survival 14.4 versus 32.8 months if SUVmax > 6.10 versus ≤ 6.10; P = 0.002) and BSI (14.7 versus 28.2 months if BSI > 1.27 versus < 1.27; P = 0.004). Only SUV was an independent factor in multivariate analysis. Conclusion: This study of progressive prostate cancer confirms earlier work that BSI is a strong prognostic factor. Most FDG-only lesions at baseline become detectable on follow-up BS, suggesting their strong clinical relevance. FDG SUV is an independent prognostic factor and provides complementary prognostic information.