A Single-Institution Prospective Study To Evaluate the Safety and Efficacy of Real- Time Image-Gated Spot-Scanning Proton Therapy (RGPT) for Prostate Cancer

Kentaro Nishioka, MD, PhD; Takayuki Hashimoto, MD, PhD; Takashi Mori, MD, PhD; Yusuke Uchinami, MD, PhD; Rumiko Kinoshita, MD, PhD; Norio Katoh, MD, PhD; Hiroshi Taguchi, MD, PhD; Koichi Yasuda, MD, PhD; Yoichi M. Ito, PhD; Seishin Takao, PhD; Masaya Tamura, PhD; Taeko Matsuura, PhD; Shinichi Shimizu, MD, PhD; Hiroki Shirato, MD, PhD; Hidefumi Aoyama, MD, PhD

Advances in Radiation Oncology (May 2024)

A Single-Institution Prospective Study To Evaluate the Safety and Efficacy of Real- Time Image-Gated Spot-Scanning Proton Therapy (RGPT) for Prostate Cancer

Kentaro Nishioka, MD, PhD,
Takayuki Hashimoto, MD, PhD,
Takashi Mori, MD, PhD,
Yusuke Uchinami, MD, PhD,
Rumiko Kinoshita, MD, PhD,
Norio Katoh, MD, PhD,
Hiroshi Taguchi, MD, PhD,
Koichi Yasuda, MD, PhD,
Yoichi M. Ito, PhD,
Seishin Takao, PhD,
Masaya Tamura, PhD,
Taeko Matsuura, PhD,
Shinichi Shimizu, MD, PhD,
Hiroki Shirato, MD, PhD,
Hidefumi Aoyama, MD, PhD

Affiliations

Kentaro Nishioka, MD, PhD: Radiation Oncology Division, Global Center for Biomedical Science and Engineering, Faculty of Medicine, Hokkaido University, Sapporo, Japan; Corresponding author: Kentaro Nishioka, MD, PhD
Takayuki Hashimoto, MD, PhD: Radiation Oncology Division, Global Center for Biomedical Science and Engineering, Faculty of Medicine, Hokkaido University, Sapporo, Japan
Takashi Mori, MD, PhD: Department of Radiation Oncology, Hokkaido University Hospital, Sapporo, Japan
Yusuke Uchinami, MD, PhD: Department of Radiation Oncology, Hokkaido University Hospital, Sapporo, Japan
Rumiko Kinoshita, MD, PhD: Department of Radiation Oncology, Hokkaido University Hospital, Sapporo, Japan
Norio Katoh, MD, PhD: Department of Radiation Oncology, Hokkaido University Faculty of Medicine, Sapporo, Japan
Hiroshi Taguchi, MD, PhD: Department of Radiation Oncology, Hokkaido University Hospital, Sapporo, Japan
Koichi Yasuda, MD, PhD: Department of Radiation Oncology, Hokkaido University Hospital, Sapporo, Japan
Yoichi M. Ito, PhD: Data Science Center, Promotion Unit, Institute of Health Science Innovation for Medical Care, Hokkaido University Hospital, Sapporo, Japan
Seishin Takao, PhD: Proton Beam Therapy Center, Hokkaido University Hospital, Sapporo, Japan
Masaya Tamura, PhD: Proton Beam Therapy Center, Hokkaido University Hospital, Sapporo, Japan
Taeko Matsuura, PhD: Proton Beam Therapy Center, Hokkaido University Hospital, Sapporo, Japan
Shinichi Shimizu, MD, PhD: Department of Carbon Ion Radiotherapy, Osaka University Graduate School of Medicine, Osaka, Japan
Hiroki Shirato, MD, PhD: Radiation Oncology Division, Global Center for Biomedical Science and Engineering, Faculty of Medicine, Hokkaido University, Sapporo, Japan
Hidefumi Aoyama, MD, PhD: Department of Radiation Oncology, Hokkaido University Faculty of Medicine, Sapporo, Japan

Journal volume & issue: Vol. 9, no. 5
p. 101464

Abstract

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Purpose: In real-time image-gated spot-scanning proton therapy (RGPT), the dose distribution is distorted by gold fiducial markers placed in the prostate. Distortion can be suppressed by using small markers and more than 2 fields, but additional fields may increase the dose to organs at risk. Therefore, we conducted a prospective study to evaluate the safety and short-term clinical outcome of RGPT for prostate cancer. Methods and Materials: Based on the previously reported frequency of early adverse events (AE) and the noninferiority margin of 10%, the required number of cases was calculated to be 43 using the one-sample binomial test by the Southwest Oncology Group statistical tools with the one-sided significance level of 2.5% and the power 80%. Patients with localized prostate cancer were enrolled and 3 to 4 pure gold fiducial markers of 1.5-mm diameter were inserted in the prostate. The prescribed dose was 70 Gy(relative biologic effectiveness) in 30 fractions, and treatment was performed with 3 fields from the left, right, and the back, or 4 fields from either side of slightly anterior and posterior oblique fields. The primary endpoint was the frequency of early AE (≥grade 2) and the secondary endpoint was the biochemical relapse-free survival rate and the frequency of late AE. Results: Forty-five cases were enrolled between 2015 and 2017, and all patients completed the treatment protocol. The median follow-up period was 63.0 months. The frequency of early AE (≥grade 2) was observed in 4 cases (8.9%), therefore the noninferiority was verified. The overall 5-year biochemical relapse-free survival rate was 88.9%. As late AE, grade 2 rectal bleeding was observed in 8 cases (17.8%). Conclusions: The RGPT for prostate cancer with 1.5-mm markers and 3- or 4- fields was as safe as conventional proton therapy in early AE, and its efficacy was comparable with previous studies.

Published in Advances in Radiation Oncology

ISSN: 2452-1094 (Online)
Publisher: Elsevier
Country of publisher: United States
LCC subjects: Medicine: Medicine (General): Medical physics. Medical radiology. Nuclear medicine; Medicine: Internal medicine: Neoplasms. Tumors. Oncology. Including cancer and carcinogens
Website: http://www.journals.elsevier.com/advances-in-radiation-oncology/

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