Imaging , Diagnosis , Prognosis Prognostic Value of Baseline [ 18 F ] Fluorodeoxyglucose Positron Emission Tomography and 99 mTc-MDP Bone Scan in Progressing Metastatic Prostate Cancer

Purpose: To compare the diagnostic and prognostic value of [F] 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 1⁄4 36) or at least 5 years (n 1⁄4 7). Imaging findings were correlated with survival. Results: Osseous lesions were detected in 39 patients on BS and 32 on FDG-PET (P 1⁄4 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 1⁄4 0.002) and BSI (14.7 versus 28.2 months if BSI > 1.27 versus < 1.27; P 1⁄4 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. Clin Cancer Res; 16(24); 6093–99. 2010 AACR. The prognosis of patients with prostate cancer varies widely at all points in the disease. Even in the setting of progressive castration resistance, which represents the lethal variant of the disease, the survival of an individual patient can vary from months to years (1). To better define risk, several studies have focused on clinical or biological parameters, patterns of spread, and/or disease extent. Few of these analyses include quantitative measures of disease burden. PSA doubling time has been proposed as a potential surrogate of disease activity. However, a method that provides a direct measure of disease activity is clearly needed. For prostate cancer, this requires developing more reliable methods to assess disease in bone, the most common site of metastasis. Several prognostic models have been reported on the basis of the number lesions on Tc-MDP bone scan (BS) or pattern of spread (axial or appendicular; refs. 2, 3). In previous work, we used standard man bone weights, and a semiquantitative estimation technique to develop a new parameter, the bone scan index (BSI), which provides a quantitative measure of the percentage of the adult skeleton involved by tumor (4). Using BSI, survival times vary inversely with disease extent. We also showed that the early spread of prostate cancer to bone is highly confined to regions of the skeleton that normally contain active red marrow in the adult male (5). More recently, we have explored the use of [F] fluorodeoxyglucose positron emission tomography (FDG-PET), which has the potential to provide amore direct measure of disease activity. In a pilot study of patients with progressive castrate resistant disease, we showed that at least 1 FDGpositive lesions was present in all the 14 patients with positive BS, and that the individual FDG-positive lesion was clinically relevant (6). Here, we expand on these findings in a larger group of patients studied under a prospective protocol, and investigate the utility of standardized uptake value (SUVmax), a measure of FDG accumulation in metastatic lesions, as a potential biomarker in progressive prostate cancer. Authors' Affiliations: Nuclear Medicine Service, Department of Radiology, Biostatistics Service, Department of Epidemiology and Biostatistics, Department of Medical Physics, and Genitourinary Oncology Service, Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, New York Note: G.S. P. Meirelles and H. Sch€ oder contributed equally to this study. Corresponding Author: Steven M. Larson, Nuclear Medicine Service, Department of Radiology, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021. Phone: 212-639-7379; Fax 212-7173263; E-mail: larsons@mskcc.org doi: 10.1158/1078-0432.CCR-10-1357 2010 American Association for Cancer Research. Clinical Cancer Research www.aacrjournals. org 6093 on April 19, 2017. © 2010 American Association for Cancer Research. clincancerres.aacrjournals. org Downloaded from Published OnlineFirst October 25, 2010; DOI: 10.1158/1078-0432.CCR-10-1357