Pretreatment 3T multiparametric MRI staging predicts for biochemical failure in high-risk prostate cancer treated with combination high-dose-rate brachytherapy and external beam radiotherapy

John V Hegde; D Jeffrey Demanes; Darlene Veruttipong; Jagdeep Raince; Sang-June Park; Steven S Raman; Nicholas G Nickols; Christopher R King; Amar U Kishan; Michael L Steinberg; Mitchell Kamrava

doi:10.1016/j.brachy.2017.07.008

Pretreatment 3T multiparametric MRI staging predicts for biochemical failure in high-risk prostate cancer treated with combination high-dose-rate brachytherapy and external beam radiotherapy

Brachytherapy. 2017 Nov-Dec;16(6):1106-1112. doi: 10.1016/j.brachy.2017.07.008. Epub 2017 Aug 12.

Affiliations

¹ Department of Radiation Oncology, University of California Los Angeles, David Geffen School of Medicine, Los Angeles, CA. Electronic address: jhegde@mednet.ucla.edu.
² Department of Radiation Oncology, University of California Los Angeles, David Geffen School of Medicine, Los Angeles, CA.
³ Departments of Radiology, Urology, and Surgery, University of California Los Angeles, David Geffen School of Medicine, Los Angeles, CA.
⁴ Department of Radiation Oncology, Samuel Oschin Cancer Center, Cedars-Sinai Medical Center, Los Angeles, CA.

PMID: 28807747
DOI: 10.1016/j.brachy.2017.07.008

Abstract

Purpose: To determine whether pretreatment 3T multiparametric MRI (mpMRI) staging impacts biochemical recurrence-free survival (BRFS) or distant metastasis-free survival (DMFS) for men with high-risk prostate cancer treated with combination high-dose-rate (HDR) brachytherapy and external beam radiation therapy (EBRT).

Materials and methods: This institutional review board-approved retrospective study included a cohort of 37 men with high-risk prostate cancer treated with HDR brachytherapy and EBRT after 3T mpMRI. Kaplan-Meier analysis was used to evaluate whether mpMRI evidence of extracapsular extension or seminal vesicle invasion (SVI) resulted in differences in BRFS or DMFS. Pretreatment and treatment-related variables were evaluated for association with biochemical failure (Phoenix definition) and distant metastatic failure using univariate Cox regression analysis.

Results: The median prostate-specific antigen at diagnosis was 9 ng/mL (range 2-100). Biopsy Gleason score (bGS) was ≤8 in 38% and nine in 62%. Clinical T-category was T1-T2 in 89%, T3a in 8%, and T3b in 3%. With a median followup of 30.6 months, actuarial 3-year BRFS and DMFS were 76% and 86%, respectively. Kaplan-Meier analysis revealed that mpMRI evidence of extracapsular extension or SVI resulted in significantly higher rates of both biochemical recurrence and distant failure. Using Cox regression analysis, only mpMRI evidence of SVI vs. no SVI predicted for biochemical failure (hazard ratio 13.98, p = 0.0055).

Conclusions: For high-risk prostate cancer treated with combination HDR brachytherapy and EBRT, mpMRI evidence of SVI predicted for biochemical failure, whereas traditional pretreatment variables did not. Therefore, pretreatment 3T mpMRI appears useful for identifying men who may benefit from treatment intensification.

Keywords: Biochemical recurrence; Distant metastasis; External beam radiotherapy; HDR brachytherapy; High-risk prostate cancer; Multiparametric MRI.

Publication types

Observational Study

MeSH terms

Aged
Aged, 80 and over
Brachytherapy / methods*
Humans
Kaplan-Meier Estimate
Magnetic Resonance Imaging / methods
Male
Middle Aged
Neoplasm Grading
Neoplasm Invasiveness
Neoplasm Staging / methods
Prognosis
Proportional Hazards Models
Prostate-Specific Antigen / blood
Prostatic Neoplasms / blood
Prostatic Neoplasms / diagnostic imaging
Prostatic Neoplasms / pathology
Prostatic Neoplasms / radiotherapy*
Radiotherapy Dosage
Retrospective Studies
Seminal Vesicles / diagnostic imaging
Seminal Vesicles / pathology
Treatment Failure

Substances

Prostate-Specific Antigen