Variability of treatment planning of seed implantation: A Japanese multicenter simulation study

This multicenter study was conducted to evaluate the current variability of treatment planning of seed implantation in Japanese centers and the feasibility of two virtual trials.

Two types of contour data were sent to 12 radiation oncologists with a request letter that asked them to make treatment plans on the data in the same manner as in their own practice. Five of the 12 radiation oncologists were asked to participate in the two virtual trials in which the D90 (dose to the hottest 90% of prostate volume) was 1) required to be set at just 180 Gy and 2) increased as much as possible without violating other limitations.

A relatively high dose with a small deviation was irradiated to the prostate in Japanese centers (mean D90 = 188 Gy; SD = 10 Gy). In the virtual trials, all five physicians could achieve 180 Gy for the D90 with a very small deviation, although the urethral dose showed relatively large deviations. Dose escalation without increase of urethral dose or V150 was difficult, although the rectum could be spared by most of the physicians.

Our study showed a relatively high dose with a small deviation was prescribed to the prostate in Japanese centers. Consolidated protocols such as D90 = 180 Gy could be available for future trials. Meanwhile, our study suggested that some cautions might be needed for urethral dose and the V150, even when a relatively low D90 was requested.

Brachytherapy. 2017 Jun 13 [Epub ahead of print]

Hiromichi Ishiyama, Masahiro Nakano, Kazuhito Toya, Ryuichi Kota, Koyo Kikuchi, Takahiro Yamaguchi, Naoaki Kono, Shogo Kawakami, Yuki Tsutsumi, Tomoki Tanaka, Takahisa Eriguchi, Saiji Ohga, Toshihiro Yamaguchi, Yoshiaki Takakawa, Masashi Morita, Norihisa Katayama, Toshio Ohashi, Manabu Aoki, Atsunori Yorozu, Siro Saito

Department of Radiology and Radiation Oncology, Kitasato University School of Medicine, Kanagawa, Japan. Electronic address: ., Department of Urology, Gifu University School of Medicine, Gifu, Japan., Department of Radiology, International University of Health and Welfare, Mita Hospital, Tokyo, Japan., Department of Radiation Oncology, Keio University School of Medicine, Tokyo, Japan., Department of Radiology, Iwate Medical School of Medicine, Iwate, Japan., Department of Radiology, Gifu University School of Medicine, Gifu, Japan., Department of Radiology, Shiga University of Medical Science, Shiga, Japan., Department of Radiology and Radiation Oncology, Kitasato University School of Medicine, Kanagawa, Japan., Department of Radiology, The Jikei University School of Medicine, Tokyo, Japan., Department of Radiology, Kyusyu University School of Medicine, Fukuoka, Japan., Department of Urology, Showa University Koto Toyosu Hospital, Tokyo, Japan., Department of Radiology, Okayama University School of Medicine, Okayama, Japan., Department of Radiology, National Hospital Organization Tokyo Medical Center, Meguro-ku, Tokyo, Japan., Department of Urology, National Hospital Organization Tokyo Medical Center, Meguro-ku, Tokyo, Japan.

E-Newsletters

Newsletter subscription

Free Daily and Weekly newsletters offered by content of interest

The fields of GU Oncology and Urology are rapidly advancing. Sign up today for articles, videos, conference highlights and abstracts from peer-review publications by disease and condition delivered to your inbox and read on the go.

Subscribe