Strahlentherapie und Onkologie

, Volume 195, Issue 5, pp 412–419 | Cite as

Institutional patient accrual volume and the treatment quality of I‑125 prostate seed implantation in a Japanese nationwide prospective cohort study

  • Katsumasa NakamuraEmail author
  • Saiji Ohga
  • Atsunori Yorozu
  • Shiro Saito
  • Takashi Kikuchi
  • Takushi Dokiya
  • Masanori Fukushima
  • Hidetoshi Yamanaka
Original Article



It is unclear whether experience at high-volume institute improves the treatment quality of prostate seed implantation. The aim of this study was to evaluate the effect of institutional experience on postimplant dosimetric parameters in a nationwide prospective cohort study.


From July 2005 to June 2007, 2354 patients were registered in the Japanese Prostate Cancer Outcome Study of Permanent I‑125 Seed Implantation (J-POPS), and 1126 patients treated with seed implantation alone were evaluated. As a surrogate for institutional experience, we classified the J‑POPS institutions as high-volume (patient accrual volume was ≥120 patients per institution) or low-volume institutions (patient accrual volume was <120 patients per institution). To compare treatment quality between institutions, we evaluated the postimplant dosimetric parameters including D90, V100/150 (prostatic dose parameters), UD5/90, U200 (urethral dose parameters), and rectum R100/150 (rectal dose parameters).


In the 5 high-volume institutions (n = 601 patients), most of the patients were treated with >144 Gy of D90, whereas in the 20 low-volume institutions (n = 525) some of the patients were treated with <144 Gy. The V100 of most of the high-volume institution patients were >90%, whereas in the low-volume institutions a considerable percentage of patients showed lower V100. Although there was no correlation between D90 and rectal dose parameters, UD90 had a moderate positive correlation with D90 in both the high- and low-volume institutions. U200 varied more widely in the low-volume institutions.


Our findings indicate that the institutional patient accrual volume is associated with the treatment quality of I‑125 prostate seed implantation.


Prostate cancer Brachytherapy Institutional experience Treatment quality Dose-volume histogram 

Institutionelle Behandlungsvolumen und Therapiequalität der I‑125-Seed-Implantation beim Prostatakarzinom in einer japanweiten prospektiven Kohortenstudie



Es ist unklar, ob eine Therapie an spezialisierten Zentren mit hohem Behandlungsvolumen die Behandlungsqualität der Seed-Implantation beim Prostatakarzinom verbessert. Ziel war es, in einer landesweiten prospektiven Kohortenstudie den Einfluss der institutionellen Erfahrung auf dosimetrische Postimplantatparameter zu untersuchen.


Von Juli 2005 bis Juni 2007 wurden 2354 Patienten für die Japanese Prostate Cancer Outcome Study of Permanent I‑125 seed Implantation (J-POPS) registriert, wovon 1126 Patienten, die mit einer alleinigen Seed-Implantation behandelt wurden, evaluiert werden konnten. Als Surrogat für die Behandlungserfahrung klassifizierten wir die J‑POPS-Einrichtungen in erfahrene Zentren (>120 Patienten pro Zentrum, „high“) und Zentren mit geringem Eingriffsvolumen (<120 Patienten pro Zentrum, „low“). Um die Behandlungsqualität zwischen den Institutionen zu vergleichen, haben wir die dosimetrischen Postimplantatparameter einschließlich D90, V100/150 (Parameter der prostatischen Dosis), UD5/90, U200 (urethrale Dosisparameter) und Rektum R100/150 (Parameter der rektalen Dosis) ausgewertet.


In den fünf Einrichtungen mit großem Behandlungsaufkommen („high“, n = 601) wurden die meisten Patienten mit einer D90 von >140 Gy behandelt, wohingegen in den 25 Instituten mit geringerem Behandlungsaufkommen („low“, n = 525) eine bedeutende Anzahl an Patienten mit einer D90 von <140 Gy behandelt wurden. Die V100 der meisten Patienten an „High-Instituten“ war >90%, wohingegen ein erheblicher Anteil der Patienten an „Low-Instituten“ eine niedrigere V100 zeigte. Obwohl es keine Korrelation zwischen D90 und den rektalen Dosisparametern gab, zeigte sich eine moderat positive Korrelation zwischen UD90 und D90, sowohl in der „High-Gruppe“ als auch „Low-Gruppe“. U200 variierte stärker in der „Low-Gruppe“.


Unsere Ergebnisse zeigen, dass das institutionelle Behandlungsvolumen mit der Behandlungsqualität einer I‑125-Seed-Implantation beim Prostatakarzinom assoziiert ist.


Prostatakrebs Brachytherapie Institutionelle Erfahrung Behandlungsqualität Dosis-Volumen-Histogramm 



We want to thank Denise Bernhardt for German language editing. The financial support by a Health Labor Sciences Research Grant (H29-ICT-Ippan-002) from the Ministry of Health, Labor and Welfare of Japan is gratefully acknowledged.


This research was in part supported by a Health Labor Sciences Research Grant (H29-ICT-Ippan-002) from the Ministry of Health, Labor and Welfare of Japan. J‑POPS study was funded by Nihon Medi-Physics Co., Ltd.

Compliance with ethical guidelines

Conflict of interest

K. Nakamura, S. Ohga, A. Yorozu, S. Saito, T. Kikuchi, T. Dokiya, M. Fukushima and H. Yamanaka declare that they have no competing interests.

Ethical standards

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Department of Radiation OncologyHamamatsu University School of MedicineHamamatsuJapan
  2. 2.Department of Clinical Radiology, Graduate School of Medical SciencesKyushu UniversityFukuokaJapan
  3. 3.Department of RadiologyNational HospitalOrganization Tokyo Medical CenterTokyoJapan
  4. 4.Department of UrologyNational Hospital Organization Tokyo Medical CenterTokyoJapan
  5. 5.Translational Research Center for Medical InnovationHyogoJapan
  6. 6.Department of RadiologySasaki Foundation Kyoundo HospitalTokyoJapan
  7. 7.Japanese Foundation for Prostate ResearchTokyoJapan

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