Predictive factors of long-term rectal toxicity following permanent iodine-125 prostate brachytherapy with or without supplemental external beam radiation therapy in 2216 patients

Tomoaki Tanaka, Atsunori Yorozu, Shinya Sutani, Yasuto Yagi, Toru Nishiyama, Yutaka Shiraishi, Toshio Ohashi, Takashi Hanada, Shiro Saito, Kazuhito Toya, Naoyuki Shigematsu

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Abstract

Purpose: We analyzed factors associated with rectal toxicity after iodine-125 prostate brachytherapy (BT) with or without external beam radiation therapy (EBRT). Methods and Materials: In total, 2216 prostate cancer patients underwent iodine-125 BT with or without EBRT between 2003 and 2013. The median followup was 6.9 years. Cox proportional hazards modeling was used for univariate and multivariate analyses to assess clinical and dosimetric factors associated with rectal toxicity. Dosimetric parameters from 1 day after implantation (Day 1) and 1 month after implantation (Day 30) were included in the analyses. Results: The 7-year cumulative incidence of Grade 2 or higher rectal toxicity was 5.7% in all patients. The multivariate analysis revealed that antiplatelet or anticoagulant therapy, neoadjuvant androgen deprivation therapy, treatment modality, Day 1 rectal volume receiving 100% of the prescribed dose (RV100), and the Day 30 minimal percent of the prescribed dose delivered to 30% of the rectum (RD30) were associated with rectal toxicity. Day 1 RV100 was a common predictor in both BT-alone and the BT + EBRT groups. The 5-year cumulative incidence of Grade 2 or higher rectal toxicity was 12.6%, 5.9%, and 1.7% for BT + 3-dimensional conformal radiation therapy, BT + intensity-modulated radiation therapy, and the BT-alone groups, respectively (p < 0.001). Conclusions: Rectal dosimetric parameters in BT were associated with late rectal toxicity. Although the risk of rectal toxicity was higher when EBRT was combined with BT, with proper and achievable rectal dose constraints intensity-modulated radiation therapy yielded less toxicity than 3-dimensional conformal radiation therapy.

Original languageEnglish
JournalBrachytherapy
DOIs
Publication statusAccepted/In press - 2018 Jan 1

Fingerprint

Brachytherapy
Iodine
Prostate
Radiotherapy
Multivariate Analysis
Neoadjuvant Therapy
Incidence
Rectum
Anticoagulants
Androgens
Prostatic Neoplasms
Therapeutics

Keywords

  • Brachytherapy
  • External beam radiation therapy
  • Intensity modulated radiation therapy
  • Prostate cancer
  • Rectal toxicity

ASJC Scopus subject areas

  • Oncology
  • Radiology Nuclear Medicine and imaging

Cite this

@article{dd2aedc52be54fa6ac850e29625d4e05,
title = "Predictive factors of long-term rectal toxicity following permanent iodine-125 prostate brachytherapy with or without supplemental external beam radiation therapy in 2216 patients",
abstract = "Purpose: We analyzed factors associated with rectal toxicity after iodine-125 prostate brachytherapy (BT) with or without external beam radiation therapy (EBRT). Methods and Materials: In total, 2216 prostate cancer patients underwent iodine-125 BT with or without EBRT between 2003 and 2013. The median followup was 6.9 years. Cox proportional hazards modeling was used for univariate and multivariate analyses to assess clinical and dosimetric factors associated with rectal toxicity. Dosimetric parameters from 1 day after implantation (Day 1) and 1 month after implantation (Day 30) were included in the analyses. Results: The 7-year cumulative incidence of Grade 2 or higher rectal toxicity was 5.7{\%} in all patients. The multivariate analysis revealed that antiplatelet or anticoagulant therapy, neoadjuvant androgen deprivation therapy, treatment modality, Day 1 rectal volume receiving 100{\%} of the prescribed dose (RV100), and the Day 30 minimal percent of the prescribed dose delivered to 30{\%} of the rectum (RD30) were associated with rectal toxicity. Day 1 RV100 was a common predictor in both BT-alone and the BT + EBRT groups. The 5-year cumulative incidence of Grade 2 or higher rectal toxicity was 12.6{\%}, 5.9{\%}, and 1.7{\%} for BT + 3-dimensional conformal radiation therapy, BT + intensity-modulated radiation therapy, and the BT-alone groups, respectively (p < 0.001). Conclusions: Rectal dosimetric parameters in BT were associated with late rectal toxicity. Although the risk of rectal toxicity was higher when EBRT was combined with BT, with proper and achievable rectal dose constraints intensity-modulated radiation therapy yielded less toxicity than 3-dimensional conformal radiation therapy.",
keywords = "Brachytherapy, External beam radiation therapy, Intensity modulated radiation therapy, Prostate cancer, Rectal toxicity",
author = "Tomoaki Tanaka and Atsunori Yorozu and Shinya Sutani and Yasuto Yagi and Toru Nishiyama and Yutaka Shiraishi and Toshio Ohashi and Takashi Hanada and Shiro Saito and Kazuhito Toya and Naoyuki Shigematsu",
year = "2018",
month = "1",
day = "1",
doi = "10.1016/j.brachy.2018.05.008",
language = "English",
journal = "Brachytherapy",
issn = "1538-4721",
publisher = "Elsevier Inc.",

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TY - JOUR

T1 - Predictive factors of long-term rectal toxicity following permanent iodine-125 prostate brachytherapy with or without supplemental external beam radiation therapy in 2216 patients

AU - Tanaka, Tomoaki

AU - Yorozu, Atsunori

AU - Sutani, Shinya

AU - Yagi, Yasuto

AU - Nishiyama, Toru

AU - Shiraishi, Yutaka

AU - Ohashi, Toshio

AU - Hanada, Takashi

AU - Saito, Shiro

AU - Toya, Kazuhito

AU - Shigematsu, Naoyuki

PY - 2018/1/1

Y1 - 2018/1/1

N2 - Purpose: We analyzed factors associated with rectal toxicity after iodine-125 prostate brachytherapy (BT) with or without external beam radiation therapy (EBRT). Methods and Materials: In total, 2216 prostate cancer patients underwent iodine-125 BT with or without EBRT between 2003 and 2013. The median followup was 6.9 years. Cox proportional hazards modeling was used for univariate and multivariate analyses to assess clinical and dosimetric factors associated with rectal toxicity. Dosimetric parameters from 1 day after implantation (Day 1) and 1 month after implantation (Day 30) were included in the analyses. Results: The 7-year cumulative incidence of Grade 2 or higher rectal toxicity was 5.7% in all patients. The multivariate analysis revealed that antiplatelet or anticoagulant therapy, neoadjuvant androgen deprivation therapy, treatment modality, Day 1 rectal volume receiving 100% of the prescribed dose (RV100), and the Day 30 minimal percent of the prescribed dose delivered to 30% of the rectum (RD30) were associated with rectal toxicity. Day 1 RV100 was a common predictor in both BT-alone and the BT + EBRT groups. The 5-year cumulative incidence of Grade 2 or higher rectal toxicity was 12.6%, 5.9%, and 1.7% for BT + 3-dimensional conformal radiation therapy, BT + intensity-modulated radiation therapy, and the BT-alone groups, respectively (p < 0.001). Conclusions: Rectal dosimetric parameters in BT were associated with late rectal toxicity. Although the risk of rectal toxicity was higher when EBRT was combined with BT, with proper and achievable rectal dose constraints intensity-modulated radiation therapy yielded less toxicity than 3-dimensional conformal radiation therapy.

AB - Purpose: We analyzed factors associated with rectal toxicity after iodine-125 prostate brachytherapy (BT) with or without external beam radiation therapy (EBRT). Methods and Materials: In total, 2216 prostate cancer patients underwent iodine-125 BT with or without EBRT between 2003 and 2013. The median followup was 6.9 years. Cox proportional hazards modeling was used for univariate and multivariate analyses to assess clinical and dosimetric factors associated with rectal toxicity. Dosimetric parameters from 1 day after implantation (Day 1) and 1 month after implantation (Day 30) were included in the analyses. Results: The 7-year cumulative incidence of Grade 2 or higher rectal toxicity was 5.7% in all patients. The multivariate analysis revealed that antiplatelet or anticoagulant therapy, neoadjuvant androgen deprivation therapy, treatment modality, Day 1 rectal volume receiving 100% of the prescribed dose (RV100), and the Day 30 minimal percent of the prescribed dose delivered to 30% of the rectum (RD30) were associated with rectal toxicity. Day 1 RV100 was a common predictor in both BT-alone and the BT + EBRT groups. The 5-year cumulative incidence of Grade 2 or higher rectal toxicity was 12.6%, 5.9%, and 1.7% for BT + 3-dimensional conformal radiation therapy, BT + intensity-modulated radiation therapy, and the BT-alone groups, respectively (p < 0.001). Conclusions: Rectal dosimetric parameters in BT were associated with late rectal toxicity. Although the risk of rectal toxicity was higher when EBRT was combined with BT, with proper and achievable rectal dose constraints intensity-modulated radiation therapy yielded less toxicity than 3-dimensional conformal radiation therapy.

KW - Brachytherapy

KW - External beam radiation therapy

KW - Intensity modulated radiation therapy

KW - Prostate cancer

KW - Rectal toxicity

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U2 - 10.1016/j.brachy.2018.05.008

DO - 10.1016/j.brachy.2018.05.008

M3 - Article

JO - Brachytherapy

JF - Brachytherapy

SN - 1538-4721

ER -