Abstract
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Purpose: A prospective, multicenter registry trial was conducted to assess disease detection rate and PET-directed change in the clinical management of men with suspected limited recurrent prostate cancer after primary therapy who subsequently had 18F-DCFPyL PET/CT (=PSMA PET) (NCT03718260).
Methods: The first 410 men enrolled in the study (December 2018-October 2019) formed the basis for this preliminary analysis. Eligibility included biochemical failure after primary therapy, either no or limited (≤4 sites) disease on conventional imaging (CT and bone scintigraphy) and one of the following predefined clinical cohorts: 1. Node positive or detectable serum PSA after radical prostatectomy (RP) 2. Post RP; 3. Post RP and pelvic radiotherapy; 4. Post RP or primary radiotherapy and androgen deprivation therapy; 5. Post radiotherapy for oligometastases; 6. Post primary radiotherapy. Results: 261/410 men (64%) had PET-detected lesions. PET detection rates among men with negative conventional imaging was 174/310 (56%). Among men with lesions on conventional imaging, new lesions were seen on PET in 63/100 (63%). Detection rate of any lesion by PSA level at enrollment were 54/139 (39%) for PSA <0.5; 49/78 (63%) 0.5-1.0 and 157/191 (82%) for PSA >1.0. On PSMA PET 49/410 men (12%) had local only disease, 95/410 (23%) had regional nodal without distant disease, and 117/410 (29%) had distant disease (non-regional nodal, bony or visceral); overall 144/410 (35%) had recurrent disease localized to the pelvis. The results for each cohort are presented in Table 1. Post PSMA PET planned management was recorded in 341/410 men. 66% (226/341) had a PET-directed change in management. The most common change was conversion from observation or systemic therapy to surgery or radiation for loco-regional (n=74) or oligometastatic disease (n=30) or alternatively the addition of nodal-directed therapy to salvage surgery or radiation (n=37). Conclusion: Preliminary data from this prospective multicenter trial suggests the high detection rate of additional disease by PSMA PET in men with suspected low volume metastatic disease results in frequent change in management. Long term follow-up is needed to determine whether this impacts disease control.
