Pattern of Progression after Stereotactic Body Radiotherapy for Oligometastatic Prostate Cancer Nodal Recurrences

Area of Science:

• Oncology
• Radiation Oncology
• Urologic Oncology

Background:

• Oligometastatic recurrence in prostate cancer (PCa) presents a unique clinical challenge.
• Stereotactic body radiotherapy (SBRT) is an emerging treatment modality for limited metastatic disease.

Purpose of the Study:

• To investigate the relapse patterns following SBRT in patients with oligorecurrent nodal prostate cancer.
• To assess the safety and efficacy of SBRT in this specific patient population.

Main Methods:

• Retrospective analysis of PCa patients with ≤3 lymph node metastases (N1/M1a) treated with SBRT.
• SBRT delivered at ≥5 Gy/fraction to a BED of ≥80 Gy to all metastatic sites.
• Evaluation of distant progression-free survival, local control, time to palliative androgen deprivation therapy, and toxicity (CTCAE v4.0).

Main Results:

• A total of 89 metastases in 72 patients were treated with SBRT.
• Median distant progression-free survival was 21 months; 88% of patients had ≤3 metastases at progression.
• Most relapses (68%) occurred in nodal regions, with subsequent relapses often remaining oligometastatic and nodal.

Conclusions:

• SBRT is a safe treatment option for oligometastatic nodal recurrences in prostate cancer.
• Subsequent disease progression after SBRT frequently involves nodal and oligometastatic patterns, similar to the initial recurrence.
• SBRT may help delay the need for systemic therapies like androgen deprivation therapy.