Dr. Declan Murphy’s talk started with a brief outline of the history of PSMA, noting that interest has dated back to 2014 when we started seeing compelling case-reports of PSMA-imaging detecting otherwise occult sites of extraprostatic disease. He then spent the remainder of the time reviewing the recent results of the proPSMA trial, Prostate-specific membrane antigen PET-CT in patients with high-risk prostate cancer before curative-intent surgery or radiotherapy (proPSMA): a prospective, randomised, multicentre study.
The proPSMA trial was published this past spring in The Lancet 1 and is a multicentre, two arm, randomized study in Australia investigating the role of PSMA in the newly diagnosed high risk prostate cancer patient. The study was initially launched in 2017, with a schema as outlined below (figure 1). Patients with high risk biopsy proven prostate cancer were randomized to either conventional imaging or PSMA- PET. As long as less than 3 metastatic lesions were identified, participants crossed-over and were imaged using the other modality. At each point, diagnosis, first imaging and second imaging, the treatment plan was recorded.
Figure 1:
The primary outcome of the study was the accuracy of the first-line imaging with regards to either pelvic nodal or distant-metastatic disease at 6 months. Extraprostatic disease was defined by a predefined reference standard including histopathology, and or changes in imaging and biochemistry at follow up. In their cohort, 30% of patients had evidence of extraprostatic disease and within the patient population PSMA PET was 27% more accurate than conventional imaging (Figure2). Subgroup analysis found that this held true for both nodal and distant disease.
Figure 2:
Next, Dr. Murphy reviewed the numerous secondary outcomes (Figure 3). The PSMA had a stronger impact on changing the management plan in both the first and second-line setting. In particular, when conventional imaging followed PSMA, little additional information was gained. This was in direct opposition to when PSMA followed conventional imaging, where 27% of the time there was a change in the management plan. Additionally, PSMA reduced the number of equivocal studies, improved inter-reporter agreement, and reduced patient radiation exposure.
Concluding his talk, Dr. Murphy highlighted the promising role that he believes PSMA-PET CT will play in the future for patients diagnosed with prostate cancer, while acknowledging the need for long term oncologic outcome studies.
Presented by: Declan Murphy, MB, BCH, BaO, FRACS, FRCS, Urol, Professor, Consultant urological surgeon at Peter MacCallum Cancer Centre and the Royal Melbourne Hospital, Melbourne, Australia and Director of Outcomes Research at the Australian Prostate Cancer Research Centre.
Written by: Adrien Bernstein, MD, Society of Urologic Oncology Fellow, Fox Chase Cancer Center, Fox Chase Cancer Center, Philadelphia, PA, at the 21th Annual Meeting of the Society of Urologic Oncology (SUO), December 3-5, Virtual Conference
References:
Related Content:
PSMA PET/CT Imaging for Staging High-risk Prostate Cancer Prior to Curative-intent Surgery or Radiotherapy (proPSMA) - Michael Hofman and Declan Murphy
The Lancet Abstract: Prostate-Specific Membrane Antigen PET-CT in Patients with High-Risk Prostate Cancer Before Curative-Intent Surgery or Radiotherapy (proPSMA): A Prospective, Randomised, Multi-Centre Study