Understanding and Improving ¹⁸F-Fluciclovine PET/CT Reports: A Guide for Physicians Treating Patients with Biochemical Recurrence of Prostate Cancer

Abstract

The positron emission tomography (PET) tracer 18F-fluciclovine has seen increasing use to localize disease in men with biochemical recurrence of prostate cancer, i.e., elevated prostate-specific antigen (PSA) levels post-treatment. 18F-Fluciclovine PET/computed tomography (CT) imaging reports now play central roles in many physician-patient discussions. However, because no standardized grading system or templates yet exist for 18F-fluciclovine image assessment, reports vary in format, comprehensiveness, and terminology and may be challenging to fully understand. To better utilize these documents, referring physicians should be aware of six key features of 18F-fluciclovine PET/CT. First, 18F-fluciclovine is a radiolabeled synthetic amino acid targeting the amino acid transporters ASCT2 and LAT1, which are ubiquitous throughout the body, but overexpressed in prostate cancer. Second, 18F-fluciclovine image interpretation is predominantly visual/qualitative: radiotracer uptake in suspicious lesions is compared with uptake in bone marrow or blood pool. Location of 18F-fluciclovine-avid lesions relative to typical recurrence sites and findings elsewhere in the patient are considered when evaluating lesions’ probability of malignancy, as is visibility on maximum intensity projection images when assessing bone lesions. Third, 18F-fluciclovine PET/CT detection rates increase as PSA levels rise. Fourth, detection rates may differ among centers, possibly due to equipment and reader experience. Fifth, since no diagnostic test is 100% accurate, scan data should not be used in isolation. Lastly, 18F-fluciclovine PET/CT findings frequently induce changes in disease management plans. In the prospective multicenter LOCATE and FALCON studies, scans altered management plans in 59% (126/213) and 64% (66/104) of patients, respectively; 78% (98/126) and 65% (43/66) of changes, respectively, involved modality switches. Referring physicians and imagers should collaborate to improve scan reports. Referrers should clearly convey critical information, including prescan PSA levels, and open clinical questions. Imagers should produce reports that read like consultations, avoid leaving open questions, and if needed, provide thoughts on next diagnostic steps.

18F-Fluciclovine PET/CT performance in biochemical recurrence of prostate cancer: a systematic review

“…This is evidenced by only 9 out of 321 trials assessed being deemed suitable for inclusion. As previously reported, 18 F-fluciclovine detection rates may differ between centers, possibly due differences in acquisition protocols, scanner type, and/or readers' experience levels [21,22]. It may be that unfamiliarity with 18 Ffluciclovine reporting influenced results, but it has been shown that following limited specific training, naïve readers are able to read 18 F-fluciclovine images with good agreement [23].…”

Quantification of Equivocal Findings in F18-Fluciclovine PET/CT Scans for Biochemical Recurrence of Localized Prostate Cancer

“…Since the approval of the F18-fluciclovine radiotracer by the United States FDA in May of 2016, the F18-fluciclovine PET/CT has become an increasingly popular tool used by providers to assess for prostate cancer recurrence [8,16]. It has been shown that the inclusion of F18-fluciclovine PET/CT into postprostatectomy radiotherapy decision-making and planning significantly improved survival free from biochemical recurrence or persistence [9,10].…”