PSMA PET/CT prior to salvage radiotherapy may improve overall survival

Undergoing prostate-specific membrane antigen (PSMA) PET/CT prior to salvage radiotherapy was associated with improved overall survival (OS) and biochemical recurrence-free survival (BRFS) in patients with biochemically recurrent prostate cancer, according to data from a cohort study published in the Journal of Nuclear Medicine.¹

“PSMA PET/CT was introduced in Denmark in 2015; however not all regions adopted the imaging modality at once,” explained lead author Anna W. Mogensen, MSc, a PhD student at the Department of Nuclear Medicine at Aalborg University Hospital in Aalborg, Denmark, in a news release on the findings.² “Utilizing Denmark’s nationwide health registry, my colleagues and I compiled a large and comprehensive dataset to compare the overall survival between patients who underwent PSMA PET/CT before salvage radiotherapy and those who did not.”

In total, the investigators included real-world data from 844 patients who received salvage radiotherapy in Denmark from 2015 to 2023. Patients were included in the study only if they had a prostate-specific antigen level of 0.2 to 1.0 ng/mL. The primary end point was OS up to 5 years following salvage radiotherapy, with BRFS as a secondary end point.

Among the 844 patients enrolled, 308 (36.5%) patients underwent PSMA PET/CT and 536 (63.5%) patients did not. The median follow-up was shorter in the PSMA PET/CT arm at 30.0 months (IQR, 12.4 to 46.9), compared with 68.4 months (IQR, 39.7 to 87.6) in the non-PSMA PET/CT arm. Patients in the PSMA PET/CT arm also had greater pathologically confirmed lymph node involvement than patients in the non-PSMA PET/CT arm (12.3% vs 9.9%, respectively).

Overall, data showed that patients who underwent PSMA PET/CT prior to salvage radiotherapy demonstrated improved OS rates compared with patients who did not receive a scan (crude HR, 3.31; 95% CI, 1.01 to 10.88; P = .0486). Specifically, at 1 year, the OS rate was 100% (95% CI, 100 to 100) among patients who received PSMA PET/CT vs 99% (95% CI, 98.2 to 99.9) among those who did not. At 2- and 5 years, these rates were 99.5% (95% CI, 98.6 to 100) vs 97.8% (95% CI, 96.5 to 99.1) and 98.1% (95% CI, 96 to 100) vs 93.8% (95% CI, 91.5 to 96.2), respectively.

Further, the 1-year BRFS rate was 91.3% (95% CI, 88 to 94.6) in patients who underwent PSMA PET/CT vs 74.9% (95% CI, 68.5 to 81.3) in patients who did not. The 3-year BRFS rate was consistent with OS, with a rate of 74.9% (95% CI, 68.5 to 81.3) among patients who underwent PSMA PET/CT compared with a rate of 69.4% (95% CI, 65.2 to 73.7) among those who did not (adjusted HR, 1.53; 95% CI, 1.07 to 2.19; P = .0187).

According to the authors, “These BRFS rates corresponded to a relative risk reduction of 42% after 1 [year] of follow-up and 18% after 3 [years].”

Overall, the authors say that these findings support the value of PSMA PET/CT in determining which patients are likely to benefit from pre-salvage radiotherapy. However, they note several limitations of the current analysis, including the observational design of the study and the inability to control for certain confounding factors due to the limited number of events in the PSMA PET/CT group.

“Ideally, these findings should be confirmed in a randomized trial," they wrote.

“Our findings show that PSMA PET/CT scans can help clinicians select the patients most likely to experience success with salvage radiotherapy. This means fewer patients may receive unnecessary treatment, while more will be provided with the appropriate care,” Mogensen concluded in the news release.² “These findings support broader use of nuclear medicine techniques to guide therapy and suggest that integrating imaging early in treatment decisions could become a new standard in cancer care.”

REFERENCES

1. Mogensen AW, Torp-Pedersen C, Nørgaard M, et al. The use of PSMA PET/CT improves overall survival in men with biochemically recurrent prostate cancer treated with salvage radiotherapy: Real-world data from an entire country. J Nucl Med. 2025;66(8):1217-1222. doi:10.2967/jnumed.125.269996

2. PSMA PET/CT prior to salvage radiotherapy improves overall survival for prostate cancer patients: Real-world data from an entire country. News release. Society of Nuclear Medicine and Molecular Imaging. August 13, 2025. Accessed August 15, 2025. https://www.eurekalert.org/news-releases/1094622