SBRT improves PFS in addition to antiandrogen therapy. The question is, with oligomets, do we need systemic therapy in all patients? Or will SBRT be sufficient?
I encourage our FCS radiation oncologists to provide their input on this study, as well.
ARTO (ClinicalTrials.gov identifier: NCT03449719) is a multicenter, phase II randomized clinical trial testing the benefit of adding stereotactic body radiation therapy (SBRT) to abiraterone acetate and prednisone (AAP) in patients with oligometastatic castrate-resistant prostate cancer (CRPC).
All patients were affected by oligometastatic CRPC as defined as three or less nonvisceral metastatic lesions. Patients were randomly assigned 1:1 to receive either AAP alone (control arm) or AAP with concomitant SBRT to all the sites of disease (experimental arm). Primary end point was the rate of biochemical response (BR), defined as a prostate-specific antigen (PSA) decrease ≥50% from baseline measured at 6 months from treatment start. Complete BR (CBR), defined as PSA < 0.2 ng/mL at 6 months from treatment, and progression-free survival (PFS) were secondary end points.
One hundred and fifty-seven patients were enrolled between January 2019 and September 2022. BR was detected in 79.6% of patients (92% v 68.3% in the experimental v control arm, respectively), with an odds ratio (OR) of 5.34 (95% CI, 2.05 to 13.88; P = .001) in favor of the experimental arm. CBR was detected in 38.8% of patients (56% v 23.2% in the experimental v control arm, respectively), with an OR of 4.22 (95% CI, 2.12 to 8.38; P < .001). SBRT yielded a significant PFS improvement, with a hazard ratio for progression of 0.35 (95% CI, 0.21 to 0.57; P < .001) in the experimental versus control arm.
The trial reached its primary end point of biochemical control and PFS, suggesting a clinical advantage for SBRT in addition to first-line AAP treatment in patients with metastatic castration-resistant prostate cancer.
Less radiation is non-inferior, this is for low and intermediate-risk localized prostate cancer patients. Would like input from our radiation oncologists as to whether or not this adoptable?
Protons vs IMRT for localized prostate cancer showed no difference in outcome or quality of life. There will be longer f/u and other endpoints studied but the take-home message is that protons are not significantly better than photons.
Will we be replaced by AI? It seems that for radiologists, an AI system was better than the human counterpart in this study looking at prostate cancer diagnostic imaging. I doubt many of us would accept a solely computer-generated report, but this study highlights how AI may help as a supportive tool in the primary diagnostic setting. Of course, prospective validation will be needed.
10-year metastasis-free survival was 71.9% in the short-course ADT group (6 months) and 78% in the long-course ADT group (24 months). So, it seems the longer the duration, the better the outcome. 93% had a Gleason score of 7 or higher.
We know that combination PARP and antiandrogen is better than antiandrogen alone. I have wondered if we need antiancrogen on those patients. This shows that, YES, we do. The combination also was better than PARP inhibitor monotherapy in those patients carrying HRRm.
FCS Hematology Oncology Review creates a platform for our physician network to observe the most recent articles and studies available in the oncology and hematology world. By sharing these articles we are building our wealth of knowledge of new observations and treatments as they come available.
