AUTHOR=Patel Priyanka H. , Tunariu Nina , Levine Daniel S. , de Bono Johann S. , Eeles Rosalind A. , Khoo Vincent , Murray Julia , Parker Christopher C. , Pathmanathan Angela , Reid Alison , van As Nicholas , Tree Alison C. 

TITLE=Oligoprogression in Metastatic, Castrate-Resistant Prostate Cancer—Prevalence and Current Clinical Practice

JOURNAL=Frontiers in Oncology

VOLUME=Volume 12 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2022.862995

DOI=10.3389/fonc.2022.862995

ISSN=2234-943X

ABSTRACT=Aims
Oligoprogression is poorly defined in current literature. Little is known about the natural history and significance of oligoprogression in patients with hormone resistant prostate cancer on abiraterone or enzalutamide treatment (termed androgen receptor targeted therapy, ARTT). The aim of this study was to determine the prevalence of oligoprogression, describe the characteristics of oligoprogression in a cohort of patients from a single centre and identify the number of patients potentially treatable with stereotactic body radiotherapy (SBRT).

Methods
Castrate resistant prostate cancer (CRPC) patients who radiologically progressed whilst on ARTT were included. Patients with oligoprogressive disease (OPD) (≤3 lesions) on any imaging were identified in a retrospective analysis of electronic patient records. Kaplan-Meier method and log rank test were used to calculate progression-free and overall survival.

Results
In total, 102 patients with metastatic CRPC on ARTT were included. Thirty (29%) patients presented with oligoprogression (46 lesions in total); 21 (21% of total) patients had lesions suitable for SBRT. The majority of lesions were in the bone 21 (46%) or lymph nodes 15 (33%). Patients with oligoprogression whilst on ARTT had a significantly better prostate specific antigen (PSA) response on commencing ARTT compared to patients who later developed polyprogression. However, PSA doubling time immediately prior to progression did not predict for OPD. Median progression free survival to oligoprogression versus polyprogression was 16.8 vs 11.7 months. Time to further progression after oligoprogression was 13.6 months for those treated with radiotherapy (RT) for oligoprogression vs 5.7 months in those treated with continuation of ARTT alone.

Conclusions
In this study nearly a third of patients on ARTT for CRPC were found to have OPD. OPD patients had a better PSA response on ART and a longer duration on ARTT before developing OPD compared to those developing Poly-PD. Majority of patients (70%) with OPD had lesions suitable for SBRT treatment. . Prospective randomised control trials are needed to establish if there is a survival benefit of SBRT in oligoprogressive prostate cancer and to determine predictive indicators.