Abstract 1369P
Background
ARTO (NCT03449719) is a multicentre, randomized phase II trial, testing the outcomes of association between Abiraterone Acetate (AA) and stereotactic body radiotherapy (SBRT) in patients affected by oligometastatic castrate resistant prostate cancer (CRPC). Here we present early results about biochemical response after 6 months from treatment start.
Methods
Oligometastatic CRPC (≤ 3 non-visceral metastatic lesions ) were randomized 1:1 to receive either I line systemic treatment alone (abiraterone acetate, control arm) or association between systemic treatment and concomitant SBRT on all metastatic sites of disease (experimental arm). No previous therapies for metastatic CRPC were allowed. Both conventional staging and Methabolic imaging (e.g Choline or PSMA PET/CT ) were permitted. SBRT should be administered providing at least a BED3≥ 100. Complete biochemical response (CBR, defined as PSA ≤ 0.2 ng/ml at 6 months after treatment) and biochemical response at 6 months after treatment start are the endpoints of the current analysis.
Results
One hundred fourteen patients were enrolled in ARTO trial, and included in the current analysis. Overall, 38.6% had a CBR (27.6 vs 50 % in the control vs experimental arm, respectively). After adjustement for baseline PSA, OR for CBR was significantly higher for patients undergoing SBRT, with OR 2.58 (95%CI 1.16-5.76, p-value 0.021. Moreover, linear regression model showed that patients in the experimental arm had a significantly lower PSA at 6 months (p=0.004).
Conclusions
SBRT showed to significantly improve biochemical response if compared to systemic treatment alone with Abiraterone Acetate in I line metastatic CRPC patients.
Clinical trial identification
NCT03449719.
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.