Abstract
PurposeWith the availability of ultra-sensitive PSA assays, early biochemical relapse (eBCR) of prostate cancer is increasingly being detected at values much lower than the conventional threshold of 0.2 ng/ml. Accurate localisation of disease in this setting may allow treatment modification and improved outcomes, especially in patients with pelvis-confined or extra-pelvic oligometastasis (defined as up to three pelvic nodal or distant sites). We aimed to measure the detection rate of [68]Ga-PSMA-HBNED-CC (PSMA)-PET/CT and its influence on patient management in eBCR of prostate cancer following radical prostatectomy (RP).MethodsWe retrospectively identified 28 patients who underwent PSMA-PET/CT for post-RP eBCR (PSA < 0.5 ng/ml) at our tertiary care cancer centre. Two nuclear medicine physicians independently recorded the sites of PSMA-PET/CT positivity. Multidisciplinary meeting records were accessed to determine changes in management decisions following PSMA-PET/CT scans.ResultsThe mean age of patients was 65.6 years (range: 50–76.2 years); median PSA was 0.22 ng/ml (interquartile range: 0.15 ng/ml to 0.34 ng/ml). Thirteen patients (46.4%) had received radiotherapy in the past. PSMA-PET/CT was positive in 17 patients (60.7%). Only one patient had polymetastasis (> 3 sites); the remainder either had prostatectomy bed recurrence (n = 2), pelvic oligometastasis (n = 10), or extra-pelvic oligometastasis (n = 4). PSMA-PET/CT resulted in management change in 12 patients (42.8%), involving stereotactic body radiotherapy (n = 6), salvage radiotherapy (n = 4), and systemic treatment (n = 2).ConclusionsOur findings show that PSMA-PET/CT has a high detection rate in the eBCR setting following RP, with a large proportion of patients found to have fewer than three lesions. PSMA-PET/CT may be of value in patients with early PSA failure, and impact on the choice of potentially curative salvage treatments.
Highlights
Despite advances in surgical technique, post-prostatectomy biochemical relapse (BCR) remains a significant problem, with 20% to 30% patients experiencing prostate-specific antigen (PSA) failure following radical prostatectomy (RP)
Numerous studies have shown the advantage of early intervention in BCR when disease burden is low, and it has been shown that there is a loss of 2.6% biochemical control per 0.1 ng/ml rise in PSA [3]
The primary objective of our study was to evaluate the proportion of patients with post-RP early BCR (eBCR) who were diagnosed with oligometastatic recurrence outside the prostatectomy bed following Ga-68-PSMA-11 PET/CT; the secondary objective was to document changes in patient management as a result of Ga-68 PSMA-11 PET/CT examinations
Summary
Despite advances in surgical technique, post-prostatectomy biochemical relapse (BCR) remains a significant problem, with 20% to 30% patients experiencing prostate-specific antigen (PSA) failure following radical prostatectomy (RP). A proportion of these patients harbour a low disease burden within the pelvis or extrapelvic oligometastases, especially during the early stages of BCR [1, 2]. Numerous studies have shown the advantage of early intervention in BCR when disease burden is low, and it has been shown that there is a loss of 2.6% biochemical control per 0.1 ng/ml rise in PSA [3]. Following empirical SRT for BCR, a proportion of patients still relapse due to occult oligometastatic disease outside the prostate bed [6, 7]. More sensitive detection methods to localise individual disease sites could allow personalised treatment in early BCR (eBCR), defined here as PSA < 0.5 ng/ml
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