Dr. Sood began highlighting that there are many roles for imaging in prostate cancer – risk stratification, diagnosis, establishing the extent of disease (staging), and assessing for recurrence. Magnetic resonance imaging (MRI) has established a clear role in the diagnosis of prostate cancer.
He highlighted recent data among men with elevated PSA (4 to 20 ng/mL) which suggested a higher sensitivity for clinically significant cancer with the use of GaPSMA-PET/CT (100%) compared to MRI (33%). However, there was also increased identification of clinically insignificant disease. A combined approach using both of these modalities demonstrated high diagnostic accuracy. Notably, SUVmax values were associated with underlying tumor histology and thus, intraprostatic accumulation could predict the presence of clinically significant cancer.
However, more common utilization of PSMA-PET/CT has focused on the “next step” in radiographic assessment – tumor staging. In this context, a number of studies have demonstrated the sensitivity of PSMA-PET/CT for detecting tumor recurrence following local therapy at even low PSA levels. Thus, this approach is more sensitive than bone scan and has the added advantage as a whole body test capable of detecting both bony and visceral disease.
Among patients with biochemical recurrence, Dr. Sood emphasized that the use of PSMA-PET/CT was associated with positive diagnostic characteristics which could translate into meaningful changes in treatment.
He emphasized that guidelines are now recommending the use of PSMA-PET/CT in patients with biochemical recurrence and PSA >1 after radical prostatectomy and among those who may be considered for curative salvage therapy following radiotherapy.
However, there are limitations to PSMA-PET/CT which he emphasized including false-positive rates, the detection of insignificant lesions, cost, and radiation exposure. The use of PET/MRI may help to address many of these issues in his opinion.
Presented by: Rajeev Sood, MBBS, MS, MCh, the Dean at Postgraduate Institute of Medical Education and Research (PGIMER)- Ram Manohar Lohia (RML) Hospital, New Delhi, India
Written by: Christopher J.D. Wallis, Urologic Oncology Fellow, Vanderbilt University Medical Center, Contact: @WallisCJD on Twitter at the 2020 Société Internationale d'Urologie Virtual Congress (#SIU2020), October 10th - October 11th, 2020