Repeated stereotactic body radiotherapy for oligometastatic prostate cancer recurrence

Radiat Oncol. 2014 Jun 12;9:135. doi: 10.1186/1748-717X-9-135.

Abstract

Purpose: To assess the outcome of prostate cancer (PCa) patients diagnosed with oligometastatic disease at recurrence and treated with stereotactic body radiotherapy (SBRT).

Methods: Non-castrate patients with up to 3 synchronous metastases (bone and/or lymph nodes) diagnosed on positron emission tomography - computed tomography, following biochemical recurrence after local curative treatment, were treated with (repeated) SBRT to a dose of 50 Gy in 10 fractions or 30 Gy in 3 fractions. Androgen deprivation therapy-free survival (ADT-FS) defined as the time interval between the first day of SBRT and the initiation of ADT was the primary endpoint. ADT was initiated if more than 3 metastases were detected during follow-up even when patients were still asymptomatic. Secondary endpoints were local control, progression free survival (PFS) and toxicity. Toxicity was scored using the Common Terminology Criteria for Adverse Events.

Results: With a median follow-up from time of SBRT of 2 years, we treated 50 patients with 70 metastatic lesions with a local control rate of 100%. The primary involved metastatic sites were lymph nodes (54%), bone (44%), and viscera (2%). The median PFS was 19 mo (95% CI: 13-25 mo) with 75% of recurring patients having ≤3 metastases. A 2nd and 3rd course of SBRT was delivered in 19 and 6 patients respectively. This results in a median ADT-FS of 25 months (20-30 mo). On univariate analysis, only a short PSA doubling time was a significant predictor for both PFS (HR: 0.90, 95% CI: 0.82 - 0.99) and ADT-FS (HR: 0.83; 95% CI: 0.71 - 0.97). Ten patients (20%) developed toxicity following treatment, which was classified as grade I in 7 and grade II in 3 patients.

Conclusion: Repeated SBRT for oligometastatic prostate cancer postpones palliative androgen deprivation therapy with 2 years without grade III toxicity.

MeSH terms

  • Bone Neoplasms / mortality
  • Bone Neoplasms / secondary*
  • Bone Neoplasms / surgery*
  • Combined Modality Therapy
  • Female
  • Follow-Up Studies
  • Humans
  • Lymphatic Metastasis
  • Male
  • Middle Aged
  • Neoplasm Recurrence, Local / mortality
  • Neoplasm Recurrence, Local / pathology
  • Neoplasm Recurrence, Local / surgery*
  • Neoplasm Staging
  • Positron-Emission Tomography
  • Prognosis
  • Prospective Studies
  • Prostatic Neoplasms / mortality
  • Prostatic Neoplasms / pathology*
  • Prostatic Neoplasms / therapy
  • Radiosurgery*
  • Radiotherapy Dosage
  • Reoperation*
  • Survival Rate
  • Tomography, X-Ray Computed