Ten-year outcomes: the clinical utility of single photon emission computed tomography/computed tomography capromab pendetide (Prostascint) in a cohort diagnosed with localized prostate cancer.

Ten-year outcomes: the clinical utility of single photon emission computed tomography/computed tomography capromab pendetide (Prostascint) in a cohort diagnosed with localized prostate cancer.

Ellis RJ; Kaminsky DA; Zhou EH; Fu P; Chen WD; Brelin A; Faulhaber PF; Bodner D; Ellis Rodney J; Kaminsky Deborah A; Zhou Esther H; Fu Pingfu; Chen Wei-Dong; Brelin Alaina; Faulhaber Peter F; Bodner Donald

International Journal of Radiation Oncology, Biology, Physics

2011

2011-09

Purpose: To evaluate the clinical utility of capromab pendetide imaging with single photon emission computed tomography coregistration with computed tomography (SPECT/CT) in primary prostate cancer (CaP) for pretreatment prognostic staging and localization of biologic target volumes (BTV) for individualized image-guided radiotherapy dose escalation (IGRT-DE). Methods and Materials: Patients consecutively presenting for primary radiotherapy (February 1997 to December 2002), having a clinical diagnosis of localized CaP, were evaluated for tumor stage using conventional staging and SPECT/CT (N=239). Distant metastatic uptake (mets) were identified by SPECT/CT in 22 (9.2%). None of the suspected mets could be clinically confirmed. Thus, all subjects were followed without alteration in disease management. The SPECT/CT pelvic images defined BTV for IGRT-DE (+150% brachytherapy dose) without (n=150) or with (n=89) external radiation of 45 Gy. The National Comprehensive Cancer Network criteria defined risk groups (RG). The median survivor follow-up was 7 years. Biochemical disease-free survival (bDFS) was reported by clinical nadir +2 ng/mL (CN+2) criteria. Statistical analyses included Kaplan-Meier, multivariate analysis, and Concordance-index models. Results: At 10-year analyses, overall survival was 84.8% and bDFS was 84.6%. With stratification by RG, CN+2 bDFS was 93.5% for the low-RG (n=116), 78.7% for the intermediate-RG (n=94), and 68.8% for the high-RG (n=29), p=0.0002. With stratification by pretreatment SPECT/CT findings, bDFS was 65.5% in patients with suspected mets (n=22) vs. 86.6% in patients with only localized uptake (n=217), p=0.0014. CaP disease-specific survival (DSS) was 97.7% for the cohort. With stratification by SPECT/CT findings, DSS was 86.4% (with suspected mets) vs. 99.0% (localized only), p=0.0001. Using multivariate analysis, the DSS hazard ratio for SPECT/CT findings (mets vs. localized) was 3.58 (p=0.0026). Concordance-index tests, based on all data, by CN+2 bDFS criteria were 0.710 for RG alone and 0.773 for SPECT/CT + RG. Conclusions: Through long-term outcomes we demonstrate statistically significant bDFS and DSS predictive value for pretreatment capromab pendetide SPECT/CT imaging in primary CaP. Dual clinical utility is demonstrated, using SPECT/CT to define BTV for individualized IGRT-DE.

Male; Aged; Multivariate Analysis; Prognosis; Tomography; Antibodies; Human; Regression; Emission-Computed; Kaplan-Meier Estimator; X-Ray Computed – Methods; Prostate-Specific Antigen – Blood; Prostatic Neoplasms – Pathology; Brachytherapy – Methods; Monoclonal – Diagnostic Use; Prostate – Radiography; Prostatic Neoplasms – Blood; Prostatic Neoplasms – Radiography; Radioisotopes – Diagnostic Use; Single-Photon – Methods

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