Long-term outcome of magnetic resonance spectroscopic image-directed dose escalation for prostate brachytherapy Journal Article

Authors: King, M. T.; Nasser, N. J.; Mathur, N.; Cohen, G. N.; Kollmeier, M. A.; Yuen, J.; Vargas, H. A.; Pei, X.; Yamada, Y.; Zakian, K. L.; Zaider, M.; Zelefsky, M. J.
Article Title: Long-term outcome of magnetic resonance spectroscopic image-directed dose escalation for prostate brachytherapy
Abstract: PURPOSE: To report the long-term control and toxicity outcomes of patients with clinically localized prostate cancer, who underwent low-dose-rate prostate brachytherapy with magnetic resonance spectroscopic image (MRSI) directed dose escalation to intraprostatic regions. METHODS AND MATERIALS: Forty-seven consecutive patients between May 2000 and December 2003 were analyzed retrospectively. Each patient underwent a preprocedural MRSI, and MRS-positive voxels suspicious for malignancy were identified. Intraoperative planning was used to determine the optimal seed distribution to deliver a standard prescription dose to the entire prostate, while escalating the dose to MRS-positive voxels to 150% of prescription. Each patient underwent transperineal implantation of radioactive seeds followed by same-day CT for postimplant dosimetry. RESULTS: The median prostate D-90 (minimum dose received by 90% of the prostate) was 125.7% (interquartile range [IQR], 110.3-136.5%) of prescription. The median value for the MRS-positive mean dose was 229.9% (IQR, 200.0-251.9%). Median urethra D-30 and rectal D-30 values were 142.2% (137.5-168.2%) and 56.1% (40.1-63.4%), respectively. Median followup was 86.4 months (IQR, 49.8-117.6). The 10-year actuarial prostate-specific antigen relapse-free survival was 98% (95% confidence interval, 93-100%). Five patients (11%) experienced late Grade 3 urinary toxicity (e.g., urethral stricture), which improved after operative intervention. Four of these patients had dose-escalated voxels less than 1.0 cm from the urethra. CONCLUSIONS: Low-dose-rate brachytherapy with MRSI-directed dose escalation to suspicious intraprostatic regions exhibits excellent long-term biochemical control. Patients with dose-escalated voxels close to the urethra were at higher risk of late urinary stricture. (C) 2016 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.
Keywords: adenocarcinoma; radiotherapy; prostate; brachytherapy; boost; implantation; distant metastases; radiation-therapy; feasibility; tumor-control; mr spectroscopy; dose escalation; dominant intraprostatic lesions; cancer
Journal Title: Brachytherapy
Volume: 15
Issue: 3
ISSN: 1538-4721
Publisher: Elsevier Science, Inc.  
Date Published: 2016-05-01
Start Page: 266
End Page: 273
Language: English
ACCESSION: WOS:000377844200002
DOI: 10.1016/j.brachy.2016.02.003
PUBMED: 27009848
PMCID: PMC5546833
Notes: Article -- Source: Wos
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MSK Authors
  1. Michael J Zelefsky
    619 Zelefsky
  2. Yoshiya Yamada
    359 Yamada
  3. Gilad N Cohen
    132 Cohen
  4. Nitin K Mathur
    12 Mathur
  5. Marisa A Kollmeier
    144 Kollmeier
  6. Marco Zaider
    169 Zaider
  7. Kristen L Zakian
    74 Zakian
  8. Xin Pei
    98 Pei
  9. Nicola   Nasser
    7 Nasser
  10. Martin T King
    3 King