A Japanese multi-institutional phase II study of moderate hypofractionated intensity-modulated radiotherapy with image-guided technique for prostate cancer

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发表日期：

2024年4月17日

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Katsumasa Nakamura,
Keiji Nihei,
Yoshihiro Saito,
Naoto Shikama,
Shin-ei Noda,
Ryusuke Hara,
Toshiyuki Imagumbai,
Takashi Mizowaki,
Takeshi Akiba,
Etsuo Kunieda,
Masanori Someya,
Saiji Ohga,
Jiro Kawamori,
Takuyo Kozuka,
Yosuke Ota,
Koji Inaba,
Takeshi Kodaira,
Yoshiyuki Itoh,
Kouta Funakoshi,
Yoshikazu Kagami

摘要

Background

The aim of this multi-institutional phase II study was to confirm the safety and the potential efficacy of moderately hypofractionated intensity-modulated radiotherapy (IMRT) with prostate-based image-guidance for Japanese patients.

Methods

Patients with low- or intermediate-risk localized prostate cancer were eligible. Patients with a part of high risk (having only one of the following factors, cT3a, 20 < PSA ≤ 30, or GS = 8 or 9) were also included. Hypofractionated IMRT using daily image-guided technique with prostate matching was performed with a total dose of 70 Gy in 28 fractions. Neoadjuvant hormonal therapy for 4–8 months was mandatory for patients with intermediate or high-risk prostate cancer.

Results

From 20 institutions, 134 patients enrolled. The median follow-up was 5.16 years (range, 1.43–6.47 years). The number of patients with low, intermediate, and high-risk prostate cancer was 20, 80, and 34, respectively. The 5-year overall, biochemical failure-free, and clinical failure-free survival was 94.5%, 96.0%, and 99.2%, respectively. The 5-year biochemical failure-free survival for patients with low-, intermediate-, and high-risk disease was 94.1%, 97.4%, and 93.9%, respectively. The incidences of grade 2 gastrointestinal (GI) and genitourinary (GU) late toxicities at 5 years were 5.3% and 5.3%, respectively. There are no acute or late toxicities ≥ grade 3. Of 124 patients who were followed for up to 5 years, the grade 2 late GU or GI toxicities were 10.5% (90% confidence intervals, 6.3–16.2%, p = 0.0958).

Conclusion

The safety and efficacy of moderately hypofractionated IMRT with prostate-based image-guidance was confirmed among Japanese patients with prostate cancer.