18F-fluciclovine PET/CT Significantly Influences ADT Plans for Patients with Prostate Cancer

A secondary analysis of 2 treatment alterations studies demonstrated that 18F-fluciclovine PET/CT scans play a pivotal role in determining if androgen deprivation therapy is appropriate for patients with prostate cancer.

The majority of patients with prostate cancer adjusted their androgen deprivation therapy (ADT) post-scan management plan after receiving a 18F-fluciclovine PET/CT scan, according to findings presented at the 22nd Society of Urologic Oncology Annual Meeting.1

Moreover, after the scans identified lesions, plans were commonly amended to target salvage therapy and spare patients the morbidity associated with ADT, said investigators.

Specifically, a total of 93 out of 146 patients (64%) had a change in management plan following their scans. The scan results also caused 55 patients (59%) to no longer have ADT included in their care plan. Furthermore, only 25% of patients who initially had a plan to receive ADT as a monotherapy still had a plan for ADT monotherapy post 18F-fluciclovine PET/CT.

“The advent of highly sensitive molecular imaging has allowed the identification of men with oligometastatic disease to may be more optimally treated with metastasis directed therapy than with systemic treatments, such as androgen deprivation therapy,” explained Gerald L. Andriole, Jr., MD, Division of Urologic Surgery, Department of Surgery, and the Alvin J. Siteman Cancer Center, Washington University School of Medicine, in a presentation of the findings. “So, the goal of this particular study was to evaluate the impact of 18F-fluciclovine PET scans on plans to use androgen deprivation therapy in patients with biochemical recurrence.”

Investigators performed a secondary analysis of 2 treatment alteration studies: LOCATE (NCT02680041) and FALCON (NCT02680041). Out of the 317 patients with biochemical recurrence (BCR) enrolled in these studies, 146 had ADT, either as a monotherapy or in combination with another treatment modality, included in their post-scan plan.

PET/CT detection rates for prostate/prostate bed region; pelvic and extra-pelvic lymph nodes (LN); and soft tissues and bones, were determined at a per-patient level. The post hoc analysis compared post-scan treatment plans with pre-scan treatment plans and used imagining findings to stratify the data.

Sixty patients in the study were initially planned to receive ADT as a monotherapy, while 86 were initially going to receive ADT with another modality. Overall, lesions were detected in 85 patients (58%) who were planning to receive ADT. Lesions were detected in prostate/bed, pelvic LN, extra-pelvic LN, and soft tissue and bones, at rates of 30%, 25%, 13%, 2.1% and 13%, respectively.

Findings revealed that 25 patients (17%) had positivity that was limited to the prostate/prostate bed, 21 patients (14%) had 18F fluciclovine–positive pelvic nodes, and 39 patients (27%) had positive detection beyond the prostate/bed and pelvic nodes.

Notably, patients with the most disseminated disease (extra-pelvic involvement,12/30; 40%) were the patients who were likely to have a post-scan plan for ADT monotherapy. In contrast, patients with a negative scan were most likely to have a modified post-scan plan which aborted ADT (14/54; 26%). Among those whose post-scan plan aborted ADT, local disease was common.

“So, in summary, data from two prospective trials indicate that 18F-fluciclovine significantly influences the management plans for a majority of patients who had a pre-scan plan that included androgen deprivation therapy,” concluded Andriole. “Androgen deprivation therapy was aborted in about 40% of the patients originally intended to receive that and management plans were commonly amended to target salvage metastasis directed treatment to 18F-fluciclovine PET/CT abnormalities, and this spared the patients the morbidity associated with androgen deprivation therapy.”

Reference

1. Andriole GL, Scarsbrook AF, Davis P, Chaglassian A, et al. Impact of 18f-fluciclovine PET/CT on plans for ADT in patients with biochemical recurrence of prostate cancer; data analysis from 2 prospective clinical trials. Presented at: Society of Urologic Oncology 22nd Annual Meeting; November 30-December 3, 2021; Orlando, FL. Abstract 144.