⁶⁸Ga-PSMA PET/CT Imaging Predicting Intraprostatic Tumor Extent, Extracapsular Extension and Seminal Vesicle Invasion Prior to Radical Prostatectomy in Patients with Prostate Cancer / 대한핵의학회잡지

PURPOSE: ⁶⁸Ga-labeled prostate-specific membrane antigen (PSMA) ligand positron emission tomography/computed tomography (PET/CT) has shown promising results in patients with biochemical recurrence after primary therapy for prostate cancer. In this study, we evaluated the usefulness of PSMA I&T (imaging and therapy) PET/CT prior to radical prostatectomy.METHODS: The study population consisted of 21 patients with prostate cancer who underwent ⁶⁸Ga-PSMA I&T PET/CT before either open or laparoscopic radical prostatectomy. Intraprostatic tumor extent, extracapsular extension (ECE) and seminal vesicle invasion (SVI) were assessed on the PET/CT scans. Tracer uptake was quantified in terms of standardized uptake values (SUVs). Imaging findings were correlated with final whole-gland histopathology.RESULTS: Of the 21 patients, two had T stage 2b disease, nine stage 2c, six stage 3a and four stage 3b. The median Gleason score was 7. The SUV(mean) of the primary tumors was 9.5 ± 8.8. SUV(mean) was higher in tumors with ECE than in organconfined tumors (13.8 ± 11.0 vs. 5.6 ± 3.2, p = 0.029). Peak tracer uptake was significantly positively correlated with Gleason score (r(s) = 0.49, p = 0.025). Sensitivity, specificity, positive predictive value and negative predictive value were, respectively, 94.7%, 75.0%, 97.3% and 60.0% for tumor infiltration of an individual prostate lobe, 75.0%, 100.0%, 100.0% and 97.4% for SVI, and 90.0%, 90.9%, 90.0% and 90.9% for ECE, using an angulated contour of the prostate as the criterion. Tumor volume derived from ⁶⁸Ga-PSMA I&T PET/CT was significantly correlated with preoperative prostate-specific antigen value (r(p) = 0.75, p < 0.001) and tumor volume on histopathology (r(p) = 0.45, p = 0.039).CONCLUSIONS: ⁶⁸Ga-PSMA I&T PET/CT prior to radical prostatectomy can contribute to presurgical local staging of prostate cancer. In this pilot study, ⁶⁸Ga-PSMA I&T PET/CT showed promising results for prediction of lobe infiltration, ECE and SVI.

Expression of survivin in squamous cell carcinoma and transitional cell carcinoma of the urinary bladder: A comparative immunohistochemical study

PURPOSE: To compare the expression of survivin and its association with clinicopathological criteria in major types of urinary bladder carcinoma, specifically, transitional cell carcinoma with and without squamous differentiation and squamous cell carcinoma. MATERIALS AND METHODS: Immunohistochemical staining for survivin and Ki67 was performed on paraffin-embedded sections of 104 carcinomas: 52 transitional cell carcinoma, 20 transitional cell carcinoma with squamous differentiation, and 32 squamous cell carcinoma. Expression of survivin in >10% of tumor cells was described as altered survivin status. Ki67 staining in >20% of tumor cells was described as a high proliferation index. RESULTS: Altered survivin expression was detected in 60/104 specimens (58%) and was significantly more frequent in transitional cell carcinoma (78%) than in squamous cell carcinoma (38%) or transitional cell carcinoma with squamous differentiation (40%) (p<0.0001). In transitional cell carcinoma but not in squamous cell carcinoma, altered survivin status was associated with higher tumor grade, higher proliferation index, and recurrence. In the whole specimens, altered survivin expression was significantly associated with advanced stage (p<0.001), recurrence (p=0.005), distant metastasis (p<0.001), and death (p=0.001). In the multivariate analysis, altered survivin was an independent poor prognostic factor for recurrence. CONCLUSIONS: Unlike in transitional cell carcinoma, alteration of survivin expression in squamous cell carcinoma occurs less frequently and is not associated with features of tumor aggression or patient outcome. These findings raise a question: are urinary bladder carcinoma patients with squamous cell carcinoma type suitable candidates for survivin vaccine? This is an important question to be answered before approving the vaccine in management.