Study of Oligorecurrent Prostate Cancer Finds Winning Combination | MedPage Today

Radiosa trial results give hope for Oligorecurrent PC

Breakthrough in Treating Oligorecurrent Prostate Cancer

Adding Short-Term Hormone Therapy to Targeted Radiation Cuts Disease Progression Risk in Half

A groundbreaking study from Italy has demonstrated significant benefits from combining targeted radiation with a brief course of hormone therapy for men with oligorecurrent prostate cancer. This important development could change treatment approaches for many patients in this specific situation.

What is Oligorecurrent Prostate Cancer?

Oligorecurrent prostate cancer refers to a state where the cancer has returned after initial treatment with a limited number of metastases (typically 1-3 spots) detected on advanced imaging scans. This pattern of recurrence represents an opportunity for targeted treatment that may delay the need for long-term systemic therapy.

The RADIOSA Trial: A Game-Changing Study

The phase II RADIOSA trial conducted at the European Institute of Oncology in Milan enrolled 105 men with oligorecurrent prostate cancer. Patients were randomly assigned to receive either:

• SBRT alone: Stereotactic body radiotherapy targeting just the visible metastatic lesions
• SBRT plus ADT: The same targeted radiation plus 6 months of androgen deprivation therapy (hormone treatment)

Impressive Results

The results were striking:

• Disease control doubled: Median clinical progression-free survival improved from 15.1 months with radiation alone to 32.2 months when short-term hormone therapy was added
• PSA control improved: Biochemical progression-free survival (measured by PSA levels) increased from 12.6 months to 26.8 months with the combination
• More localized recurrences: The radiation-only group experienced more widespread (polymetastatic) relapses (15 patients) compared to the combination group (6 patients)
• Hormone recovery: Almost all patients who received the combination treatment regained normal testosterone levels within 1 year

Dr. Barbara Alicja Jereczek-Fossa, who led the research team, noted: "To the best of our knowledge, our study represents the first randomized effort to report the superiority of SBRT and a short course of ADT compared with SBRT alone in metachronous oligorecurrent hormone-sensitive prostate cancer."

Treatment Was Well-Tolerated

Side effects from the treatments were minimal. In the combined therapy group, the most common hormone-related side effect was hot flashes, reported by all patients who experienced any side effects. Other mild side effects included fatigue (16%), insomnia (8%), and muscle pain (4%). All side effects had resolved by the end of follow-up.

Who Might Not Need Added Hormone Therapy?

Importantly, the researchers identified specific patient groups who might do just as well with radiation alone, without the added hormone therapy:

• Men with PSA levels between 0-2 ng/mL
• Those whose PSA takes longer than 3 months to double
• Patients with non-regional lymph node metastases (M1a disease)
• Cases where recurrence occurred more than 43 months after initial treatment

What This Means for Patients

This research provides valuable guidance for men facing oligorecurrent prostate cancer. The combination approach may offer significantly better outcomes while still allowing hormone function to recover within a year.

Dr. Amar Kishan and Dr. Luca Valle of UCLA, who commented on the study, noted: "The decision to add short-course ADT to metastasis-directed therapy should still involve a detailed discussion of risks and benefits between patients and physicians."

Looking Ahead

The RADIOSA trial will continue analyzing patients' quality of life data and molecular signatures that might help identify which patients benefit most from each treatment approach. This could further refine treatment selection and personalize therapy for each patient's specific situation.

The findings were published in the March 2025 issue of Lancet Oncology.

For more information about this treatment approach or to discuss whether it might be appropriate for your situation, speak with your medical team at your next appointment.

RADIOSA Trial Summary

The RADIOSA trial was a randomized phase II clinical study that compared two treatment approaches for oligorecurrent hormone-sensitive prostate cancer (where the cancer has returned with a limited number of metastases after initial treatment).

Key Facts:

• Study location: European Institute of Oncology in Milan, Italy
• Participants: 105 men with 1-3 metastatic lesions detected on advanced imaging
• Study design: Patients were randomly assigned to receive either SBRT alone (stereotactic body radiotherapy) or SBRT plus 6 months of ADT (androgen deprivation therapy/hormone therapy)

Primary Results:

• Clinical progression-free survival: 15.1 months with SBRT alone vs. 32.2 months with SBRT+ADT
• Biochemical progression-free survival (based on PSA): 12.6 months vs. 26.8 months
• Risk reduction: Adding ADT reduced the risk of progression or death by more than half (HR 0.43)
• Pattern of relapse: More patients in the SBRT-alone group developed widespread disease (15 vs. 6)

Side Effects:

• Minimal treatment-related toxicity in both groups
• Grade 1 ADT-related side effects (primarily hot flashes) were reported
• Almost all patients in the combination group achieved testosterone recovery within 1 year

Significance:

The study represents the first randomized trial to demonstrate superior outcomes with the combination approach. However, certain patient subgroups (those with PSA 0-2 ng/mL, PSA doubling time >3 months, M1a disease, or >43 months from initial treatment) may derive similar benefits from SBRT alone.

The findings support a short-term combined treatment approach for oligorecurrent prostate cancer while highlighting the importance of patient selection for optimal treatment decisions.

 

Study of Oligorecurrent Prostate Cancer Finds Winning Combination | MedPage Today

— Adding a short course of androgen deprivation to SBRT cut risk of disease progression in half

by Mike Bassett, Staff Writer, MedPage Today March 5, 2025 medpagetoday.com

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Oncology/Hematology > Prostate Cancer

• Addition of 6 months of androgen deprivation therapy to stereotactic body radiotherapy more than doubled PFS in hormone-sensitive oligorecurrent prostate cancer.
• Nearly all patients treated with the combination achieved testosterone recovery at 1 year.
• Certain subgroups may still derive similar benefit from stereotactic body radiotherapy alone.

A short course of androgen deprivation therapy (ADT) added to stereotactic body radiotherapy (SBRT) halved the risk of disease progression or death in patients with metachronous oligometastatic hormone-sensitive prostate cancer, a phase II study showed.

Median clinical progression-free survival (PFS) doubled from 15.1 months with SBRT alone to 32.2 months with the addition of 6 months of ADT (HR 0.43, 95% CI 0.26-0.72, P=0.0010), reported Barbara Alicja Jereczek-Fossa, MD, PhD, of the European Institute of Oncology in Milan, and colleagues.

Meanwhile, median biochemical PFS improved from 12.6 months to 26.8 months, respectively (HR 0.40, 95% CI 0.24-0.66, P=0.0002), according to findings detailed in Lancet Oncologyopens in a new tab or window.

"To the best of our knowledge, our study represents the first randomized effort to report the superiority, in terms of clinical progression-free survival, of SBRT and a [short course of ADT] compared with SBRT alone in metachronous oligorecurrent hormone-sensitive prostate cancer," wrote Jereczek-Fossa and co-authors.

"Considering that almost all patients in the combined treatment group achieved testosterone recovery at 1 year, the results support that this short term (intermittent) combined approach is an optimal option in selected patients with metachronous oligorecurrent hormone-sensitive prostate cancer," the research team added.

They emphasized "the importance of patient selection in treatment decisions" as a significant PFS advantage with ADT was not observed in those with a prostate-specific membrane antigen (PSA) concentration of 0-2 ng/mL, a PSA doubling time of more than 3 months, and M1a disease stage at baseline, along with patients whose time from first curative treatment to SBRT was more than 43 months.

"These data demonstrate that, perhaps as expected, adding a short course of ADT to metastasis-directed therapy [MDT] improves clinical progression-free survival," wrote Amar Kishan, MD, and Luca Valle, MD, both of the University of California Los Angeles, in a commentary accompanying the studyopens in a new tab or window.

"The data also suggest that this effect might be mediated primarily by suppressing occult disease rather than by eradicating it. Although physician-scored toxicity might be modest, the known effect of ADT on quality of life (which was not reported) can be substantial," they added. "Thus, the decision to add short-course ADT to MDT should still involve a detailed discussion of risks and benefits between patients and physicians."

Medical News from Around the Web

The RADIOSA studyopens in a new tab or window from Jereczek-Fossa and colleagues was an open-label phase II trial conducted at the IRCCS European Institute of Oncology in Milan. The study randomized 105 adults to either SBRT alone (30 Gy in three fractions every other day or equivalent regimens depending on disease location) or in combination with 6 months of ADT.

Patients were eligible if they had an initial diagnosis of adenocarcinoma of the prostate, biochemical progression after radical local prostate treatment, nodal relapse in the pelvis, extra-regional nodal relapse, bone metastases at next-generation imaging with a maximum of three lesions, good performance status.

Participants had a median age of 70 years; race and ethnicity data were not collected. Most patients (64%) presented with one oligometastasis at enrollment, 26% with two, and 10% with three oligometastatic lesions.

The study's primary endpoint was clinical PFS, defined as the time from randomization until the presence of new local, regional, or distant metastatic lesions at staging examination, or death from any cause. Secondary endpoints included overall survival (OS) and biochemical PFS, among others.

OS was immature at the time of analysis, with post-hoc analysis showing 1- and 2-year rates of 100% and 95%, respectively, for the overall study population.

Regarding safety, one grade 3 adverse event (AE) occurred in one patient in the combination group, a left ureter stenosis. In addition, one patient in the SBRT alone group reported a gastrointestinal acute grade 1 toxicity. Both were resolved at the last follow-up.

For ADT-related toxicity, 43% in the combination group reported grade 1 AEs, the most common of which were hot flushes, reported in all of the patients reporting an AE. Other AEs reported in patients in the combination group related to ADT were asthenia in 16%, insomnia in 8%, and muscular pain in 4%.

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  Mike Bassett is a staff writer focusing on oncology and hematology. He is based in Massachusetts.

Disclosures

The study was funded by the Italian Association of Cancer Research.

Jereczek-Fossa disclosed relationships with Bayer, Accuray, Astellas, IBA, Ipsen, AstraZeneca, Tecnologie Avanzate, Recordati, Novartis, and Seagen. Co-authors reported relationships with Merck Sharp & Dohme, Merck, Novartis, AstraZeneca, Roche, Menarini, Daiichi Sankyo, GSK, Gilead, Sysmex, Veracyte, Sakura, Leica Biosystems, Lilly, Pfizer, Boston Scientific, Diffusion Pharmaceuticals, Vision RT, Bayer, Telix, Lantheus, and Molli Surgical.

Kishan reported relationships with Varian Medical Systems, Boston Scientific, Janssen, and Lantheus.

Primary Source

The Lancet Oncology

Source Reference: opens in a new tab or windowMarvaso G, et al "ADT with SBRT versus SBRT alone for hormone-sensitive oligorecurrent prostate cancer (RADIOSA): a randomised, open-label, phase 2 clinical trial" Lancet Oncol 2025; DOI: 10.1016/S1470-2045(24)00730-7.