Salvage Radiotherapy Management Decisions in Postprostatectomy Patients with Recurrent Prostate Cancer Based on ¹⁸F-Fluciclovine PET/CT Guidance

Abstract

Imaging with novel PET radiotracers has significantly influenced radiotherapy decision making and radiation planning in patients with recurrent prostate cancer (PCa). The purpose of this analysis was to report the final results for management decision changes based on 18 F-fluciclovine PET/CT findings and determine whether the decision change trend remained after completion of accrual. Methods: Patients with detectable prostate-specific antigen (PSA) after prostatectomy were randomized to undergo either conventional imaging (CI) only (arm A) or CI plus 18 F-fluciclovine PET/CT (arm B) before radiotherapy. In arm B, positivity rates on CI and 18 F-fluciclovine PET/CT for detection of recurrent PCa were determined. Final decisions on whether to offer radiotherapy and whether to include only the prostate bed or also the pelvis in the radiotherapy field were based on 18 F-fluciclovine PET/CT findings. Radiotherapy decisions before and after 18 F-fluciclovine PET/CT were compared. The statistical significance of decision changes was determined using the Clopper-Pearson (exact) binomial method. Prognostic factors were compared between patients with and without decision changes. Results: All 165 patients enrolled in the study had standard-of-care CI and were initially planned to receive radiotherapy. Sixty-three of 79 (79.7%) patients (median PSA, 0.33 ng/mL) who underwent 18 F-fluciclovine PET/CT (arm B) had positive findings. 18 F-Fluciclovine PET/CT had a significantly higher positivity rate than CI did for the whole body (79.7% vs. 13.9%; P , 0.001), prostate bed (69.6% vs. 5.1%; P , 0.001), and pelvic lymph nodes (38.0% vs. 10.1%; P , 0.001). Twenty-eight of 79 (35.4%) patients had the overall radiotherapy decision changed after 18 F-fluciclovine PET/CT; in 4 of 79 (5.1%), the decision to use radiotherapy was withdrawn because of extrapelvic disease detected on 18 F-fluciclovine PET/CT. In 24 of 75 (32.0%) patients with a final decision to undergo radiotherapy, the radiotherapy field was changed. Changes in overall radiotherapy decisions and radiotherapy fields were statistically significant (P , 0.001). Overall, the mean PSA at PET was significantly different between patients with and without radiotherapy decision changes (P 5 0.033). Conclusion: 18 F-Fluciclovine PET/CT significantly altered salvage radiotherapy decisions in patients with recurrent PCa after prostatectomy. Further analysis to determine the impact of 18 F-fluciclovine PET/CT guidance on clinical outcomes after radiotherapy is in progress.

Detection Rate and Clinical Impact of PET/CT with 18F-FACBC in Patients with Biochemical Recurrence of Prostate Cancer: A Retrospective Bicentric Study

“…A further consideration has to be made regarding 18 F-FACBC PET/CT’s impact on patients’ clinical management. Our results are substantially in line with those previously reported [ 19 , 20 ], indicating a significant contribution of PET/CT in patients’ therapeutic work-flow, particularly with respect to the use of PET-directed radiotherapeutic treatments that can be successfully applied, on the one hand, in order to prolong survival and, on the other hand, to positively influence subjects’ quality of life, delaying, in some cases, the use of ADT with the consequent effects on erectile function [ 14 ]. In our study, we enrolled patients with BCR as defined according to the Phoenix criteria [ 15 ], which are commonly applied in clinical practice.…”

“…Furthermore, 18 F-FACBC PET/CT has been reported to have a relevant impact on the clinical management of patients with PC BCR, both for the choice of the most appropriate therapeutic approach (e.g., Stereotactic Body Radiation Therapy/SBRT versus systemic therapy) and the delineation of RT fields [ 14 ].…”

Prostate Cancer Skeletal Metastasis: A Spontaneous Evolution from Osteolytic to Osteoblastic Morphology without Treatment

“…In August 2020, the patient agreed to participate in an ongoing phase 3 clinical trial investigating the diagnostic performance of 18F Radiohybrid prostate-specific membrane antigen ( 18 F-rhPSMA), a novel PET radiopharmaceutical targeting PSMA, for the detection of PCa recurrence. 18 F-rhPSMA PET/CT done at a PSA of 3.78 ng/mL also demonstrated the radiotracer-avid prostate bed recurrence. The osteolytic lesion in the left pubic ramus shows radiotracer avidity on the fused PET/CT images (straight arrow in ►Fig.…”

“…CT chest, abdomen, and pelvis of November 2018 and radionuclide bone scan plus CT abdomen, abdomen, and pelvis of January 2019 were also negative for the localization of the site of recurrent PCa (images not shown). In February 2020 and at a serum PSA of 4.14 ng/mL, a repeat 18 F-fluciclovine PET/CTwas obtained, which showed an intense area radiotracer uptake in the prostate bed consistent with prostate bed recurrence of PCa (curve arrows in ►Fig. 1B).…”

The Performance of FDA-Approved PET Imaging Agents in the Detection of Prostate Cancer

“…The diagnostic performance of [ 18 F]FACBC was widely assessed after the FDA’s approval. The reported overall detection rate for [ 18 F]FACBC ranged from 40% to 80%, depending on the size of patient cohorts, and like [ 11 C]choline, its detection rate positively correlated with patients’ PSA levels(see Table 2 [ 37 , 38 , 39 , 40 , 41 , 42 , 43 ]). In a study investigating BCR patients with very low PSA levels (≤0.3 ng/mL), the detection rates were 43.8% for patients with PSA level below 0.1 ng/mL, increasing up to 65.2% for patients with PSA between 0.2 and 0.3 ng/mL [ 44 ].…”