Population outcomes of EBRT with LDR brachytherapy boost for intermediate, high-risk prostate cancer
PD-0670
Abstract
Population outcomes of EBRT with LDR brachytherapy boost for intermediate, high-risk prostate cancer
Authors: OH|, Justin(1)*[justin.oh@bccancer.bc.ca];Spadinger|, Ingrid(2);Lapointe|, Vincent(1);Morris|, James(1);
(1)BC Cancer, Radiation Oncology, Vancouver, Canada;(2)BC Cancer, Medical Physics, Vancouver, Canada;
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Purpose or Objective
To evaluate and compare the prognostic and treatment factors and oncologic outcomes of the high-intermediate (HIR) and high-risk (HR) prostate cancer patients treated with LDR-PB and EBRT with the results of Androgen Suppression Combined with Elective Nodal and Dose Escalated Radiation Therapy (ASCENDE-RT).
Material and Methods
HIR or HR prostate cancer patients were eligible for combined LDR-PB, EBRT, +/- androgen depravation therapy (ADT) treatment from 2010 – 2016 at British Columbia Cancer. All patients received prostate +/- pelvic irradiation to 46Gy followed by LDF-PB boost. ADT was given at the discretion of the treating oncologist. Disease and treatment characteristics and oncologic outcomes were prospectively collected and reviewed.
Results
568 patients received the combined modality treatment. Median age was 69 years. 69% (N=391) had NCCN HR disease, 291 (51%) had Gleason grade group (GGG) 4 or 5, and the median iPSA was 12ng/mL. 97 (17%) had clinical stage T3a or higher, and the median positive number of cores (PPC) was 57%. 243 (43%) had 2 or more high risk features (HRF). The median D90 for LDR-PB was 124.5Gy. 93% of HR and 55% of IR received ADT. 5-year relapse-free survival (RFS), metastasis-free survival (MFS), and overall survival (OS) was 85±4%, 90±3%, and 89±3%. On univariate analysis, GGG, HRF, PPC were associated with RFS. GGG and HRF were also associated with MFS. Patients who relapsed in 5 years had worse OS.
Conclusion
The combined modality treatment factors and outcomes are comparable to the results of ASCENDE-RT and remain an effective treatment option for IR and HR prostate cancer. Higher GGG, HRF, PPC are potentially associated with worse outcomes. People who had early relapse had worse OS as demonstrated by ASCENDE-RT.