(UroToday.com) The 2024 American Urological Association (AUA) Annual Meeting held in San Antonio, TX between May 3rd and 6th, 2024 was host to an advanced prostate cancer moderated poster session. Dr. Umar Ghaffar presented the results of a study evaluating PSMA-PET-guided metastasis-directed therapy for oligometastatic prostate cancer.
It is hypothesized that oligometastatic prostate cancer is an intermediary disease state existing along the prostate cancer continuum between localized and overt ‘poly’metastatic disease, although some have argued that oligometastatic disease is a biologically and phenotypically unique subtype, independent of other disease states.
With the emergence of an increased utilization of PSMA-PET, oligometastatic disease is increasingly being diagnosed in prostate cancer patients, particularly in the biochemically recurrent setting. The objective of this study was to assess the utility of PSMA-PET for improving therapeutics and diagnostics of oligometastatic prostate cancer.
The investigators reviewed 802 consecutively performed PSMA-PET/CT scans performed at The Mayo Clinic between April 2022 and November 2022. Oligometastatic disease was defined as ≤5 metastatic lesions. Treatment response was determined using pre- and post-treatment PSA levels. Clinicopathological, treatment, and follow-up data were collected. Cox regression modeling was used to identify factors predicting radiographic (RPFS) and biochemical progression-free survival (BPFS).
Dr. Ghaffar and colleagues identified 141 patients with oligometastatic disease. The mean age at diagnosis was 71.4 years. The median PSA at diagnosis was 8.7 ng/ml. The Initial definitive treatment for these patients included prostatectomy (67%) and radiotherapy (23%). 8.5% of patients had de novo oligometastatic disease. The mean number of oligometastatic sites was 2.14 lesions. The mean SUVmax of the metastatic lesions was 11, and the mean miPSMA score was 1.9. Sites of metastases included the following:
- Bone: 64%
- Nodes: 43%
- Viscera: 2.8%
Of the 141 patients, 28.6% had castrate-resistant disease at the time of diagnosis of oligometastatic disease.
Following diagnosis, patients underwent the following treatments:
- ADT: 57.4%
- Stereotactic ablative radiotherapy: 49.6%
- Intensity-modulated radiation therapy: 19%
- Cryoablation: 7%
- Chemotherapy: 5%
- Surgery: 2.1%
On serial follow-up imaging, 13.4% progressed to diffuse metastasis, 48.5% had a complete response, 32.4% had a partial response, and 10.6% had stable disease or disease progression. On multivariable logistic regression, patients who received metastasis-directed therapy + ADT had significantly decreased rates of radiographic and biochemical progression (HRs 0.32 and 0.25, respectively).
Presented by: Umar Ghaffar, MD, Research Fellow, Department of Urology, Cedars-Sinai Medical Center, Los Angeles, CA
Written by: Rashid Sayyid, MD, MSc - Society of Urologic Oncology (SUO) Clinical Fellow at The University of Toronto, @rksayyid on Twitter during the 2024 American Urological Association (AUA) Annual Meeting, San Antonio, TX, May 3rd - 6th, 2024