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BACKGROUND: The relevance of next-generation hormone therapies and circulating tumor cells (CTCs) are not elucidated in biochemical recurrence after prostatectomy. OBJECTIVE: To evaluate the combination of abiraterone acetate plus prednisone (AAP), prostate bed radiotherapy (PBRT), and goserelin in biochemically relapsing men after prostatectomy, and to investigate the utility of CTCs. DESIGN, SETTING, AND PARTICIPANTS: In this single-arm multicenter phase 2 trial, 46 biochemically relapsing men were enrolled between December 2012 and January 2019. The median follow-up was 47 mo. INTERVENTION: All patients received AAP 1000 mg daily (but 750 mg during PBRT), salvage PBRT, and goserelin. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The primary outcome was 3-yr biochemical recurrence-free survival (bRFS) when prostate-specific antigen (PSA) levels were ≥0.2 ng/ml. The secondary outcomes included alternative bRFS (alt-bRFS) when PSA levels were ≥0.5 ng/ml and safety assessment. CTC count was assessed. RESULTS AND LIMITATIONS: The 3-yr bRFS and alt-bRFS were 81.5% (95% confidence interval or CI [66.4-90.3%]) and 95.6% (95% CI [83.5-98.9%]), respectively. The most common acute radiotherapy-related adverse effect (AE; all grades was pollakiuria (41.3%). The most common late AE (all grades) was urinary incontinence (15.2%). Grade 3-4 acute or late radiotherapy-related AEs were scarce. Most frequent AEs nonrelated to radiotherapy were hot flashes (76%), hypertension (63%), and hepatic cytolysis (50%, of which 20% were of grades 3-4). Of the patients, 11% had a CTC count of ≥5, which was correlated with poorer bRFS (p = 0.042) and alt-bRFS (p = 0.008). The association between CTC count and higher rates of relapse was independent of the baseline PSA level and PSA doubling time (p = 0.42 and p = 0.09, respectively). This study was nonrandomized with a limited number of patients, and few clinical events were reported. CONCLUSIONS: Adding AAP to salvage radiation therapy and goserelin resulted in high bRFS and alt-bRFS. AEs remained manageable, although a close liver surveillance is advised. CTC count appears as a promising biomarker for prognosis and predicting response to treatment. PATIENT SUMMARY: Our study was a phase 2 clinical trial that exhibited the efficacy and tolerance of a novel androgen-receptor targeting agent (abiraterone acetate plus prednisone) in patients with prostate cancer who experienced rising prostate-specific antigen after radical prostatectomy, in combination with prostate bed radiotherapy. The results also indicated the feasibility and potential value of circulating tumor cell detection, which constitutes a possible advance in managing prostate cancers.
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OBJECTIVE: This study aimed to evaluate the usefulness of combining fluorine-18 choline (F-FCH) and fluorine-18 fluorodeoxyglucose (F-FDG) PET/computed tomography (CT) in patients with rising prostate-specific antigen and known or suspected second malignancy. MATERIALS AND METHODS: F-FCH and F-FDG PET/CT were performed 15±9 days apart on the same PET/CT system and acquisition and reconstruction parameters. A mean standardized uptake value (SUVmean) was computed for every lesion that could be discriminated with both tracers. PET results were confirmed by histology (eight patients) and clinical and imaging follow-up (mean±SD: 15±9 months). RESULTS: Of 77 consecutive patients who underwent F-FCH PET/CT scans for suspected prostate cancer recurrence, 10 (13%) were suspected to have a second malignancy because of F-FCH PET pattern inconsistency with that of prostate cancer (n=6), because of a history of a second malignancy with similar metastatic patterns (n=2) or inconsistency between disease burden and prostate-specific antigen value (n=2). Seventy lesions were studied, with a final diagnosis of prostate cancer, other cancers and benign disease in 55, nine and six lesions, respectively. F-FCH SUVmean and F-FCH/F-FDG SUVmean ratios were significantly different between prostate cancer, nonprostate cancer and benign disease (P<0.0001 and P=0.04, respectively). Receiving operating characteristic analysis showed that the F-FCH/F-FDG ratios were not better than F-FCH SUVmean in discriminating prostate cancer from nonprostate cancer and benign diseases (sensitivity, specificity and area under the curve were 69%, 80%, 0.71 and 84%, 80% and 0.89, respectively). CONCLUSION: We found that F-FCH/F-FDG SUVmean ratios cannot differentiate prostate cancer recurrences from other cancer types when both diagnoses are suspected. Doubtful lesions should be biopsied.