Effect of 18F-DCFPyL prostate-specific membrane antigen-positron emission tomography/computed tomography on the management of suspected limited residual/recurrent disease following radical prostatectomy: a prospective, multicenter registry trial in Ontario
Joseph L.K. Chin1, Ur Metser2, Katherine Zukotynski3, Victor Mak4, Deanna Langer4, Pamela MacCrostie4, Anil Kapoor5, Luke T. Lavallée6, Laurence Klotz7, Catherine Hildebrand1,8, Marlon Hagerty9, Antonio Finelli7, Glenn Bauman8.
1Surgery (Urology) , Western University , London, ON, Canada; 2Medical Imaging, University of Toronto, Toronto, ON, Canada; 3Radiology, McMaster University, Hamilton, ON, Canada; 4Cancer Care Ontario , Toronto, ON, Canada; 5Surgery (Urology), McMaster University, Hamilton, ON, Canada; 6Surgery (Urology) , University of Ottawa, Ottawa, ON, Canada; 7Surgery (Urology), University of Toronto, Toronto, ON, Canada; 8Oncology, Western University , London, ON, Canada; 9Radiation Oncology, Northwest Regional Cancer Care , Thunder Bay, ON, Canada
Cancer Care Ontario . Ontario Ministry of Health & Long-Term Care. NCT03718260.
Introduction: We aimed to assess disease detection rate of 18F-DCFPyL positron emission tomography/computed tomography (PET/CT) and management changes directed by PET results in patients with suspected limited residual or recurrent disease following radical prostatectomy (RP).
Methods: A total of 1289 patients from six Ontario cancer centers were enrolled, including 487 post-RP. Cohort 1 (C1) (n=72) were node-positive or had prostate-specific antigen (PSA) >0.1 ng/ml post-RP. Cohort 2 (C2) (n=415) had biochemical failure (BCF) post-RP, with 0–4 disease sites on CT and/or bone scan. Management intent (curative or palliative) was collected both pre- and post-prostate-specific membrane antigen (PSMA) PET/CT.
Results: PSMA-PET detected disease in 39/72(54.2%) in C1 and 188/415(45.3%) in C2. In C1 patients with node-positive disease post-RP and PSA <0.1, the detection rate was 16.7% (1/6). For C1 on PET, 22/72(30.6%) had locoregional failure, 11 (15.3%) were oligometastatic, and six (8.3%) had extensive disease. For C2, the respective data were 122/188 (29.4%), 51 (12.3%), and 15 (3.6%). Overall, management change was recorded in 212/487 (43.5%). In 91/474 men (19.2%), there was a management intent change (“intent” data unavailable in 13). In C1, 13% changed from curative to palliative intent and 10.1% from palliative to curative. For C2, 5.4% changed from curative to palliative and 13.1% from palliative to curative intent. The most common management changes for both cohorts were: 1) conversion from observation or systemic therapy to salvage radiation or surgery for locoregional disease (68/487,13.9%); and 2)addition of node-directed therapy (65/487, 13.3%).
Conclusions: Compared with standard imaging, PSMA-PET detected additional disease sites in approximately 50% of patients with BCF and suspected low-volume metastatic disease, often resulting in management change. Significantly, PSMA-PET led to therapeutic intent change in 20% of men. Long-term followup will determine if PSMA-PET will impact eventual disease outcome in patients with suspected limited residual/recurrent disease following RP.
