Imaging agent shows major impact on PCa management decisions

Findings from fluorine-18-labeled fluciclovine (¹⁸F-fluociclovine; Axumin) positron emission tomography/computed tomography (PET/CT) imaging had a major impact on management decisions for men with biochemical recurrence of prostate cancer, according to the results of a prospective, open-label, phase III clinical trial.

The study, known as FALCON (Fluciclovine [¹⁸F] PET/CT in biochemicAL reCurrence Of prostate cancer), was conducted at six centers across the United Kingdom and included 104 men who were being considered for curative-intent salvage therapy. It evaluated the impact of the scan on patient care by comparing the pre-scan intended management plan with the post-scan plan.

The whole body positivity rate for the ¹⁸-fluciclovine PET/CT scan was 56% (58/104 men), and considering the findings of the scan, the intended management plan was changed for 66 patients (64%). The majority of the changes (65%; 43/66) were classified as “major,” defined as a change of treatment class (eg, salvage radiotherapy to androgen deprivation therapy). The study results were consistent with those of a U.S. multicenter study (LOCATE) in which a change was made to the management plan for 59% of 213 men with recurrent prostate cancer based on the ¹⁸F-fluciclovine PET/CT imaging.

Speaking on behalf of the FALCON investigators, David Bottomley, MD, of St. James Institute of Oncology, Leeds, UK, presented the study’s findings at the American Society for Radiology Oncology annual meeting in Chicago. He told Urology Times¹⁸F-fluciclovine PET/CT gives clinicians greater confidence regarding accurate staging of recurrent prostate cancer because compared with conventional imaging,¹⁸F-fluciclovine PET/CT is more likely to detect existing metastatic disease. Therefore, it may facilitate optimal targeting of recurrence sites and potentially spare patients from futile localized salvage therapy.”

Dr. Bottomley continued, “Results from long-term follow-up are still needed to determine how management changes guided by ¹⁸F-fluociclovine PET/CT affect patient outcomes, and that will take some time. Nevertheless, the availability of better imaging techniques for evaluating patients with prostate cancer will lead to further studies of both men with localized recurrent prostate cancer and men with oligometastatic disease. Ultimately, this is likely to result in more tailored treatment for patients that would be expected to translate into better outcomes.”

FALCON enrolled patients between December 2015 and May 2017. Men were eligible if they had Eastern Cooperative Oncology Group performance status 0-2 and their biochemical recurrence was the first after previous radical treatment for prostate cancer. Men who had received androgen deprivation therapy or choline PET/CT within 3 months prior to screening or who had bilateral hip prostheses were excluded.

Almost two-thirds of the 104 men in the study had undergone prostatectomy as primary treatment. Median time to biochemical recurrence after initial diagnosis was 58 months.

Next: Prostate/prostate bed most common site identified as harboring recurrent disease by ¹⁸F-fluciclovine PET/CT imagingThe prostate/prostate bed was the most common site identified as harboring recurrent disease by the ¹⁸F-fluciclovine PET/CT imaging followed by the pelvic lymph nodes (18%). Possible recurrence was also detected in bone (8.7%), retroperitoneal lymph nodes (7.7%), other lymph nodes (3.8%), and soft tissue/parenchyma (2.9%).

The major changes to the treatment plan included a change from salvage treatment to watchful waiting for 16 men, a change from salvage therapy to non-curative systemic therapy in 16 men, and recommendations for alternative changes to the treatment modality in 11 men. Of the remaining 23 patients whose treatment plan was revised, the change involved modification of the intended plan for radiotherapy/brachytherapy.

Overall, 53 (80%) of the revisions were based on a positive scan result whereas the scan was negative in 33 (87%) of the cases in which the treatment plan was not revised.

No new safety concerns emerged with use of ¹⁸F-fluciclovine in the study.

Dr. Bottomley received travel support from Blue Earth Diagnostics Ltd., the company that markets ¹⁸F-fluciclovine.