Researchers from UMC Utrecht, together with an international consortium of ten European centres, have developed and externally validated a clinical prediction model for men with limited recurrent prostate cancer. The results were published in The Lancet Oncology. The study shows that after stereotactic body radiotherapy (SBRT) to all visible metastases, 84% of patients remained free from hormone therapy (androgen deprivation therapy, ADT) at one year. Delaying ADT is clinically relevant, as this systemic treatment is often associated with side effects such as fatigue, hot flashes, sexual dysfunction, metabolic changes, and loss of muscle mass.
Who were the patients in this study?
The study focused on men whose prostate cancer had returned after earlier curative treatment, with up to five metastases detected using PSMA PET imaging. This modern imaging technique can detect small metastatic lesions at an early stage. All patients received stereotactic body radiotherapy (SBRT), a highly precise form of radiotherapy directed at all PSMA PET–positive lesions. Importantly, no systemic therapy was started at the same time. The aim of this strategy was to defer or avoid ADT. In total, 586 patients were included in the development cohort and 131 patients in an independent external validation cohort.
Four factors linked to earlier hormone therapy
Using clinical data from multiple European centres, the researchers identified four factors linked to starting hormone therapy earlier: PSA level before treatment, how quickly PSA rises over time, the number of metastases, and whether the cancer had spread beyond the lymph nodes.
From prediction model to clinical decision-making
Based on these factors, the model divides patients into low-, intermediate-, and high-risk groups. It does not predict exactly what will happen for an individual patient, but it helps estimate the likelihood of needing hormone therapy sooner and supports treatment decisions in multidisciplinary teams. Further research will determine how the model can best be integrated into daily clinical practice.
“In patients whose prostate cancer recurs with a limited number of metastases, the clinical course can vary considerably,” says Timo Soeterik, radiation oncology resident and researcher at UMC Utrecht and first author of the study. “With this model, we can better estimate who is most likely to benefit from metastasis-directed radiotherapy alone and who may benefit from more intensive combined treatment approaches.”
Questions and Answers
What does this new model predict in recurrent prostate cancer?
The model predicts the likelihood that men with recurrent prostate cancer will remain free from hormone therapy (androgen deprivation therapy, ADT) after metastasis-directed radiotherapy (stereotactic body radiotherapy or SBRT). It estimates the probability of remaining ADT-free at 1 and 2 years after treatment.
What is recurrent prostate cancer with limited metastases?
Recurrent prostate cancer means the disease has returned after earlier treatment with curative intent. In this study, patients had up to five metastases detected with PSMA PET imaging, a highly sensitive scan used to identify small sites of cancer spread.
How was hormone therapy delayed in these patients?
Patients received stereotactic body radiotherapy (SBRT) directed at all visible metastases, without concurrent systemic therapy. In the development cohort, 84% remained free from hormone therapy at one year.
Which factors influence the timing of hormone therapy in prostate cancer?
The study identified four independent factors associated with earlier initiation of hormone therapy: PSA level before metastasis-directed SBRT, PSA doubling time (how quickly PSA rises), the number of metastases, and whether the cancer had spread beyond the pelvic lymph nodes.
Is this prediction model already used in clinical practice?
The model has been developed and externally validated using international real-world data. Although it is not yet part of standard guidelines, it can already support multidisciplinary decision-making. Further prospective research will determine how it can best be integrated into routine clinical practice and future clinical trials.
