Session Item

To assess the effect of radiation therapy on biochemical progression-free survival (bPFS) for patients with synchronous, oligometastatic prostate cancer (PC).

From May 2011 to May 2021, 43 patients presenting to a single center were treated for synchronous, oligometastatic PC with radiotherapy. Demographic/oncologic characteristics, treatment, and bPFS were retrospectively assessed via electronic medical record review. All patients were treated with definitive-range dosing to primary and all sites of metastatic disease will elective nodal irradation. Patients were subgrouped into those with lymph node metastases only (N1) or bone metastasis (M1). bPFS was assessed via Kaplan-Meier analysis for both groups.

Overall, the mean±SD age and pre-treatment PSA was 66.7±8.6 years and 53.3±75.9 ng/ml, respectively. 10 (23.3%) and 33 (76.7%) patients had M1 and N1 only disease, respectively. Table 1 depicts a comparison of clinicodemographics between the three groups; patients with M1 disease were significantly older compared to patients with N1 disease. 

The mean±SD duration of androgen deprivation therapy (ADT) use was 2.13±0.62 years and all patients had completed ADT by time of analysis. At a mean±SD time to follow-up of 4.67±3.02 years, 2/10 (20%) patients with M1 disease and 5/33 (15.2%) patients with N1 only disease experienced biochemical failure. bPFS were not significantly different between the two groups (Mantel-Cox p=0.552, Figure 1). Kaplan-Meier estimate (SE) for survival time was 10.6 (0.810) years.

Radiation therapy for the treatment of oligometastatic prostate cancer yielded bPFS rates of 80% and 84.8% for patients with M1 and N1 only disease.

Table 1. Clinicodemographics of all patients undergoing radiation therapy for M1 and N1 only disease.

Figure 1. Kaplan-Meier of bPFS for patients with M1 and N1M0 disease.