PSMA PET/CT scans predict progression-free survival and guide personalized treatment strategies for recurring prostate cancer.
New insights from researchers at the University of California, Los Angeles (UCLA) are refining how doctors approach treatment for men whose prostate cancer returns after initial surgery. A study published in the JNCCN highlights the growing role of prostate-specific membrane antigen (PSMA) PET/CT scans in tailoring therapy to the individual characteristics of each patient’s cancer.
The Challenge of Prostate Cancer Recurrence
Prostate cancer remains a significant health concern for men, ranking as the second most common cancer diagnosed. While many men are successfully treated with radical prostatectomy – surgical removal of the prostate – a substantial proportion, between 20% and 40%, experience a biochemical recurrence within 10 years. This recurrence is often first detected by a rising prostate-specific antigen (PSA) level in blood tests.
Standard treatment for this recurrence is salvage radiotherapy (sRT), focused on the area where the prostate was removed. However, accurately pinpointing the location of the recurrent cancer can be difficult, especially when PSA levels are low – below 1 ng/mL. Traditional imaging techniques like CT and MRI often lack the sensitivity to detect these small clusters of cancer, leading doctors to treat broader areas, potentially including nearby lymph nodes, or to initiate hormone therapy even when it may not be necessary.
PSMA PET/CT scans offer a significant improvement in detection capabilities. These scans utilize a radioactive tracer that binds to PSMA, a protein found on most prostate cancer cells. This allows for the identification of very small areas of cancer that would otherwise be invisible on standard scans, enabling more precise targeting of treatment.
Key Study Findings at UCLA
The UCLA study, which analyzed data from 113 patients treated between 2016 and 2021, demonstrated the impact of PSMA PET/CT scans on treatment decisions and outcomes. All patients underwent a PSMA PET/CT scan within three months of starting sRT and were followed for at least 24 months.
The results revealed a clear correlation between scan findings and progression-free survival (PFS). Patients with no visible evidence of cancer on the PSMA PET/CT scan (classified as T0N0M0) experienced the most favorable outcomes. In this group, whole-pelvis radiotherapy – which treats a larger area – did not offer a significant benefit compared to focusing radiation solely on the prostate bed. However, patients with locally visible disease (TrN0M0) showed a significant improvement in PFS when treated with whole-pelvis radiotherapy.
For patients with cancer that had spread to lymph nodes or distant sites (N1/M1), the addition of androgen deprivation therapy (ADT) – hormone therapy – was associated with improved PFS. Importantly, the study found that PSA levels alone were not strongly linked to long-term response to treatment, reinforcing the value of imaging-based decisions.
“PSMA PET/CT allows us to move beyond one-size-fits-all radiation therapy to treatment tailored to the anatomy and biology of each patient’s cancer,” explained John Nikitas, lead author of the study. “This approach not only improves outcomes but also reduces unnecessary side effects.”
Impact on Clinical Practice and Patient Outcomes
The five-year outcomes observed in the study are encouraging. Approximately 72.4% of patients were free from distant metastasis at five years, and overall survival was remarkably high at 97.1%. These findings suggest that PSMA PET/CT-guided sRT can significantly improve long-term control of recurrent prostate cancer.
However, the widespread adoption of PSMA PET/CT scans faces challenges. The scans are not yet universally available, and implementing them into routine clinical practice requires resources and expertise. Nikitas emphasized the importance of facilitating routine access to these scans for patients experiencing a biochemical recurrence after prostatectomy, stating, “The information from these scans is strongly associated with long-term outcomes and frequently changes treatment recommendations.”
Expert Commentary and Future Directions
An accompanying commentary published in JNCCN by Edward Christopher Dee and colleagues from Memorial Sloan Kettering Cancer Center further underscored the transformative potential of PSMA PET/CT. Dee noted, “This study shows that seeing where the cancer is, even at low PSA levels, may meaningfully shape treatment decisions and could potentially influence long-term outcomes.”
The findings highlight the potential of PSMA PET/CT to improve outcomes for patients with recurrent prostate cancer. However, ensuring equitable access to this technology remains a critical priority. Collaboration between healthcare providers, policymakers, and researchers will be essential to translate this clinical innovation into a sustainable standard of care, ultimately improving outcomes for men facing this challenging diagnosis.
Several prospective clinical trials – including PSMA-SRT, PEACE-V STORM, ADOPT, and PSICHE – are underway to further refine the use of PSMA PET/CT in guiding treatment decisions and optimizing outcomes for patients with recurrent prostate cancer.
