Distant Nodes Seen on PSMA PET-CT Staging Predicts Post-Treatment Progression in Men with Newly Diagnosed Prostate Cancer—A Prospective Cohort Study

SIMPLE SUMMARY: PSMA PET-CT is a new scan which has now been proven to be the most accurate in detecting prostate cancer outside the prostate gland. It is now recommended by international guidelines to be used before treatment is commenced for prostate cancer. However, we still do not know the true impact the information from these scans has on the treatment that we give the patients. In this study, we look at whether men who had a PSMA PET-CT scans before their treatment for prostate cancer needed any further treatment for their prostate cancer within the first 29 months of follow up. Our results found that 80% of men these men did not need any further treatment for their prostate cancer. We also found that if the prostate cancer was seen on PSMA PET-CT in lymph nodes outside of the pelvis, men were 5 times more likely to need another form of treatment within 29 months. ABSTRACT: PSMA PET-CT scans are now recommended in international urological guidelines for primary staging and re-staging of prostate cancer. However, there is little published literature on the clinical outcomes for patients after treatment decisions made using PSMA PET-CT results. This is a multisite, prospective cohort study investigating the clinical outcomes of men who received treatment plans based on PSMA PET-CT results for primary staging. Men with biopsy proven prostate cancer received a PSMA PET-CT scan for primary staging. Treatment plans were recommended by multidisciplinary teams (MDT). After treatment, these men were followed with 6 monthly PSA tests and imaging or biopsies if recommended by MDT. The primary outcome was treatment progression defined as the addition or change of any treatment modalities such as androgen deprivation therapy, radiation therapy or chemotherapy. In total, 80% of men did not have any treatment progression after enactment of treatment based on PSMA PET-CT primary staging results at 29 months of follow up. Men who had distant nodes seen on PSMA PET-CT had a 5 times increased risk of treatment progression. Larger studies with longer follow up are needed to validate our results and optimise the way clinicians use PSMA PET-CT results to guide management.