Vesico‐urethral anastomosis sampling: a forgotten tool for guiding salvage radiation after radical prostatectomy

Abstract

To review the utility of vesicourethral anastomosis (VUA)-directed biopsy in the setting of biochemical recurrence (BCR) after radical prostatectomy (RP) for prostate cancer (PCa) in patients who have undergone evaluation by gallium-68 prostate-specific membrane antigen positron emission tomography with computed tomography ( 68 Ga-PSMA PET/CT). MethodsWe completed a retrospective review of a prospectively maintained dataset from January 2015 to August 2020. Patient demographics were recorded for those who experienced BCR, as defined by a rise in prostate-specific antigen (PSA) level to above 0.2 ng/mL, who had a 68 Ga-PSMA PET/CT that did not demonstrate recurrence within the prostate bed, and who subsequently underwent a transperineal ultrasonography (TPUS)-guided biopsy directed at the VUA. Histological reporting of the biopsies was undertaken in order to determine whether the benefits of salvage radiation therapy (SRT) could be justified by the presence of cancer cells. ResultsEighteen patients who had a 68 Ga-PSMA PET/CT and underwent VUA-directed biopsy were identified as having BCR. 68 Ga-PSMA PET/CT scans demonstrated avidity at the VUA in none of the patients, although two out of 18 patients showed avidity in the seminal vesicles and two out of 18 patients showed avidity within regional lymph nodes. Histology from the TPUS-guided, VUA-directed biopsies demonstrated no prostatic tissue in six out of 18 and presence of prostatic tissue in 12 out of 18 of patients, respectively. In 7 out of 18 cases, there was histological evidence of recurrent PCa at the VUA in the absence of a positive 68 Ga-PSMA PET/CT scan. ConclusionThis study highlights the potential value of VUA-directed biopsy. We are reminded that a negative 68 Ga-PSMA PET/CT does not exclude local recurrence and that the addition of a VUA-directed biopsy may aid in the decision-making process for patients with BCR following RP, especially when 68 Ga-PSMA PET/CT is locally negative. When the result of both 68 Ga-PSMA PET/CT and VUA-directed biopsy are negative, it should encourage clinicians to share decision-making in regard to undertaking SRT vs continuing BCR surveillance. This may delay the possible side effects associated with SRT, despite its excellent PSA failure-free survival rate.

Re‐defining 18F‐DCFPyl prostate‐specific membrane antigen positron emission tomography detected local recurrence from radical prostatectomy histopathology

“…A total of 28 patients from the IMPPORT trial were identified as having local recurrences on their 18 F-DCFPyL PET scans. In all, 29.5% had nodal disease and 6.1% had bone metastasis [2].…”

“…Salvage RT improves prostate cancer‐specific survival and is offered to patients with high‐risk prostate cancer who have an elevated or rising PSA level after RP without evidence of metastatic disease [17]. Salvage RT is not without risk of side‐effects, both short term and long term, and requires stringent planning [18]. In planning salvage RT, the RT field must target the prostate bed and encompass areas of highest risk.…”

“…The focus of this study is the subset of patients from the IMPPORT trial (trial registration: Australian New Zealand Clinical Trials Registry [ANZCTR] Number: ACTRN12618001530213) who had a local recurrence detected on 18 F-DCFPyL PSMA PET [2]. The IMPPORT trial, is a prospective non-randomised study assessing the role of 18 F-DCFPyL PSMA PET in 100 men with PSA recurrence (PSA level 0.2-2.0 ng/mL) after RP being considered for salvage RT [2].…”

“…The overexpression of prostate-specific membrane antigen (PSMA) in prostate cancer cells allows for the early detection of prostate cancer recurrence after radical treatment, using positron emission tomography (PET). PSMA PET, using tracers such as 68 Ga-PSMA or 18 F-DCFPyL, is recommended for investigation of biochemical recurrence after radical prostatectomy (RP) when the PSA level is ≥0.2 ng/mL [1,2]. Since July 2022, the Australian Government has funded PSMA PET/CT for primary staging and biochemical recurrence through the Medical Benefits Scheme [3].…”

“…As this pelvic recurrence is distant from the anastomosis itself, Dundee et al[16] discussed the issue of targeting the visualised local recurrence only that would in turn reduce the morbidity of RT to the urethra and anastomosis. Although the detection of PSMA PET local recurrences will ensure coverage by RT volumes, Koschel et al[2] reported in just under 100 patients receiving18 F-DCFPyL PSMA PET for biochemical recurrence after RP, 48.4% of patients had a negative scan. Horsley et al[19] mapped the distribution of 140 local recurrences, validating consensus clinical target volume guidelines.…”