There is increasing worldwide interest in exploring stereotactic ablative body radiotherapy (SABR) for treating metastases in men with prostate cancer, including for the treatment of oligoprogressive metastases. The latter applies to a situation whereby patients with widespread metastases undergoing systemic therapy present with a solitary or a few metastatic tumors that progress, while all other metastases are stable or responding. The usual practice would be to change systemic therapy at this point, but another approach is to locally ablate the "rogue" metastases and continue the same systemic therapy. SABR used in this scenario may delay the need to switch to another line of systemic therapy and improve progression-free survival while patients stay on the same systemic therapy.
ECOG performance status 0-1.
Histologic confirmation of prostate adenocarcinoma.
Documentation of metastatic, castration-resistant prostate cancer.
Patient being treated with abiraterone.
Patients presenting with unequivocal clinical progression, defined as one of the following: (i) cancer pain requiring the initiation of opioid therapy; (ii) immediate need for cytotoxic chemotherapy as per treating physician's discretion; or (iii) deterioration of performance status to grade ≥ 3 according to ECOG.
Evidence of spinal cord compression.
Prior malignancy within the past 5 years, excluding non-melanoma skin cancer, and in-situ cancer.
Single group
Stereotactic Body Radiation Therapy (SABR)
RadiationSABR to oligoprogressive metastases while continuing abiraterone therapy
SABR-related toxicities
Incidence of acute and late toxicities (including radiation induced bone fractures) after comprehensive SABR to all progressing metastases seen on conventional imaging.
Progression-free survival
Time to clinical (i.e., radiological and/or symptomatic) progression following SABR.
Biochemical progression-free survival
Time to PSA progression
Time to changing systemic therapy
Time to starting subsequent line of systemic therapy
Radiographic local control rate of the SABR-treated areas
Monitoring lack of progression of oligoprogressive sites of disease
Radiographic distant progression-free survival
Time to metastatic progression outside of SABR-treated areas
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