title: Influence of zonal dosimetry on prostate brachytherapy outcomes.
abstract: OBJECTIVE
  To examine the influence of zone-specific dosimetry on outcomes during permanent prostate implantation (PI), where the peripheral zone (PZ) and transitional zone (TZ) may receive varying radiation doses.
  
  
  METHODS
  Four hundred and sixteen patients treated with I-125 PI (target dose: 144 Gy) between 1996 and 2003 were included in this Institutional Review Board (IRB) approved, retrospective analysis. Whole prostate (WP), TZ, and PZ were contoured, and zone-specific D90 and V100 were computed. Their influence on biochemical failure (BF) was evaluated using Cox proportional hazards analysis.
  
  
  RESULTS
  The median age and initial prostate-specific antigen (PSA) was 68 years and 6.1 ng/ml, respectively, and the median follow-up time was 8.8 years. There were 329 subjects with Gleason score (GS) 6 disease (79.1%), and 82 subjects had GS 7 disease (19.7%). Androgen deprivation therapy (ADT) was used in 20.4% of patients. Median D90 and V100% in the WP, PZ, and TZ were 141.2 Gy, 156.1 Gy, and 134.5 Gy; and 88.8%, 93.3%, and 84.2%, respectively. Ten-year rates for biochemical recurrence-free survival, distant metastasis-free survival, and prostate cancer-specific mortality were 82.4%, 92.4%, and 0.97% respectively. Only initial PSA, GS7+ disease, ADT, and PSA frequency were significant on multivariate analysis. Ten-year rates of grade 3 or higher GU and GI toxicity was 10.9% and 1.8%, respectively. TZ V200 and TZ V300 were significantly associated with late genitourinary toxicity.
  
  
  CONCLUSIONS
  The TZ received significantly lower doses of radiation compared to the PZ. On multivariate analysis, no dosimetric parameter was associated with efficacy. Higher TZ doses may be associated with higher late GU toxicity without improving efficacy.
authors.affiliation: Lerner College of Medicine, Cleveland Clinic, Cleveland, OH.
authors.forename: Cheng William
authors.initials: CW
authors.lastname: Hong
authors.affiliation: Department of Radiation Oncology, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH.
authors.forename: Chandana A
authors.initials: CA
authors.lastname: Reddy
authors.affiliation: Department of Radiation Oncology, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH.
authors.forename: D Allan
authors.initials: DA
authors.lastname: Wilkinson
authors.affiliation: Department of Urology, Glickman Urological and Kidney Institute, Cleveland Clinic, Cleveland, OH, USA.
authors.forename: Eric A
authors.initials: EA
authors.lastname: Klein
authors.affiliation: Department of Radiation Oncology, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH.
authors.forename: Jay P
authors.initials: JP
authors.lastname: Ciezki
keywords: prostate cancer; toxicity; zonal dosimetry
references.citation: Cancer. 2002 Nov 15;95(10):2126-35
references.pmid: 12412166
references.citation: Urology. 2003 Jan;61(1):152-5
references.pmid: 12559287
references.citation: Int J Radiat Oncol Biol Phys. 1999 Jul 1;44(4):789-99
references.pmid: 10386635
references.citation: Int J Radiat Oncol Biol Phys. 2004 Dec 1;60(5):1347-50
references.pmid: 15590163
references.citation: Radiother Oncol. 2009 May;91(2):237-42
references.pmid: 19167121
references.citation: Brachytherapy. 2011 Mar-Apr;10 (2):107-16
references.pmid: 20724223
references.citation: Int J Radiat Oncol Biol Phys. 2011 Sep 1;81(1):1-7
references.pmid: 21470793
references.citation: Int J Radiat Oncol Biol Phys. 2000 Jan 1;46(1):83-8
references.pmid: 10656377
references.citation: J Contemp Brachytherapy. 2013 Mar;5(1):33-41
references.pmid: 23634153
references.citation: Radiother Oncol. 2006 Jan;78(1):41-6
references.pmid: 16271785
references.citation: J Urol. 2009 Apr;181(4):1665-71; discussion 1671
references.pmid: 19233394
references.citation: Cancer. 2007 Apr 15;109(8):1506-12
references.pmid: 17340591
references.citation: J Urol. 2008 May;179(5 Suppl):S20-4
references.pmid: 18405743
references.citation: J Contemp Brachytherapy. 2013 Jun;5(2):63-9
references.pmid: 23878549
references.citation: Brachytherapy. 2006 Oct-Dec;5(4):239-43
references.pmid: 17118317
references.citation: Brachytherapy. 2014 Jul-Aug;13(4):369-74
references.pmid: 24559795
references.citation: J Clin Oncol. 1996 Feb;14(2):449-53
references.pmid: 8636756
references.citation: Am J Surg Pathol. 1988 Dec;12(12):897-906
references.pmid: 3202246
references.citation: Prostate. 1981;2(1):35-49
references.pmid: 7279811
references.citation: Int J Radiat Oncol Biol Phys. 2005 Oct 1;63(2):472-8
references.pmid: 16168839
references.citation: Brachytherapy. 2011 Mar-Apr;10(2):87-97
references.pmid: 20691643
references.citation: Int J Radiat Oncol Biol Phys. 2006 Jul 15;65(4):965-74
references.pmid: 16798415
references.citation: Int J Radiat Oncol Biol Phys. 2002 Oct 1;54(2):457-61
references.pmid: 12243822
references.citation: Int J Radiat Oncol Biol Phys. 2005 Oct 1;63(2):479-91
references.pmid: 16168840
references.citation: Int J Radiat Oncol Biol Phys. 2000 Nov 1;48(4):1241-4
references.pmid: 11072184
references.citation: Int J Radiat Oncol Biol Phys. 2007 Feb 1;67(2):327-33
references.pmid: 17084558
references.citation: Brachytherapy. 2009 Jan-Mar;8(1):45-51
references.pmid: 19038584
references.citation: Int J Radiat Oncol Biol Phys. 2004 Apr 1;58(5):1540-8
references.pmid: 15050335
references.citation: J Contemp Brachytherapy. 2013 Jun;5(2):89-92
references.pmid: 23878553