Annual Report 2024
Department of Radiation Oncology
Hiroshi Igaki, Kae Okuma, Tomoya Kaneda, Koichi Inaba, Kana Takahashi, Tairo Kashihara, Ayaka Nagao, Madoka Sakuramachi, Akane Yoshiba
Introduction
The role of our department is to provide state-of-the-art radiation therapy to all patients who need it, to educate and develop the expertise of radiation oncologists, radiation technologists, and medical physicists, and to lead new developments in radiation oncology in Japan and globally. All departmental activities are dedicated to cancer patients. A linear accelerator-based neutron irradiation system for boron neutron capture therapy (BNCT) has been installed in the hospital; an epithermal neutron beam was obtained and a clinical trial of BNCT for cutaneous angiosarcoma is ongoing.
The Team and What We Do
Our department treats the largest number of patients requiring radiation therapy in Japan. Four linear accelerators, a CyberKnife, a MR linear accelerator, a brachytherapy system, four XCT-simulators, and 19 treatment planning computers are working together in online networks to provide state-of-the-art high-precision external beam radiation therapy. In addition to the conventional X-ray and electron therapies, stereotactic irradiations of brain and body tumors and intensity-modulated radiation therapy (IMRT) are routinely performed. Stereotactic brain irradiation is performed with CyberKnife for metastatic and primary brain tumor treatment. Stereotactic body radiation therapies are performed for lung liver, kidney and pancreas tumors under respiratory gating in linear accelerators or CyberKnife. All linear accelerators have on-board kilovoltage cone-beam CT imagers, which assist in precisely aligning patient and tumor coordinates. These image-guided radiation therapy (IGRT) machines enable the precise delivery of IMRT in head and neck cancers, brain tumors, prostate cancers, postoperative cervical cancers, and other cancers. Brachytherapy is also performed to improve local control, with the following modalities: an Ir-192 high dose rate (HDR) remote after-loading system, including a dedicated CT simulator and fluoroscopy, and other low dose rate (LDR) brachytherapy systems using Au-198 grains and Ru-106 eye plaques. HDR interstitial irradiation is performed mainly in gynecological, genitourinary, and head and neck tumors. Additionally, there are two beds in the shielded ward on Floor 13B. Ru-106 mold therapy is performed in collaboration with ophthalmologists to treat retinoblastomas and choroidal melanomas. LDR interstitial implants are conducted using Au-198 grains for the management of head and neck tumors and gynecological malignancies. The number of patients treated in our department is shown in Table 1.
Research Activities
Clinical research is an essential component of the daily activities of our department. The primary interests of the research activities of the department are as follows: (1) clinical applications of accelerator-based boron neutron capture therapy for skin, chest, and other tumors; (2) on-line adaptive radiation therapy using an MR linear accelerator system; (3) image-guided brachytherapy for genitourinary, gynecologic, and head and neck cancers; (4) development of new medical devices for radiotherapy; (5) hypofractionated stereotactic irradiation of brain and body tumors; (6) an optimal fractionation regimen for pain palliation of bone metastasis.
Clinical Trials
Many clinical trials are ongoing, as shown below.
JCOG studies for lung cancers, head and neck cancers, brain tumors, gynecological cancer, esophageal cancers, and others.
International NRG studies for breast cancer, meningioma, and metastatic brain tumors.
Multi-institutional phase II clinical trial of on-line adaptive stereotactic body radiotherapy for prostate cancer using MR linear accelerators.
Phase II clinical trial of BNCT for skin angiosarcoma.
Phase I/II clinical trial of BNCT for basket type chest malignant tumors.
Many other multi- or single-institutional clinical trials are also ongoing or in preparation.
Education
Residents are trained in all fields of radiation oncology in our department. Seminars on biology, physics, and clinical radiation oncology are regularly held in the evening.
Future Prospects
With the expanding of radiation therapy indications, additional manpower will be required, and research perspectives will be considerably broadened. Radiation oncology is one of the most promising disciplines in oncology.
List of papers published in 2024
Journal
1. Sekino Y, Sonoda Y, Shibahara I, Mizusawa J, Sasaki K, Sekita T, Ichikawa M, Igaki H, Kinoshita M, Kumabe T, Shibahara J, Ichimura K, Arakawa Y, Fukuda H, Narita Y. Protocol digest of a phase III randomized trial of gross total resection versus possible resection of fluid-attenuated inversion recovery-hyperintense lesion on MRI for newly diagnosed supratentorial glioblastoma: JCOG2209 (FLAMINGO). Japanese journal of clinical oncology, 55:75-79, 2025
2. Takada M, Yagi N, Nakamura S, Shimada K, Itami J, Igaki H, Nakamura M, Nunomiya T, Endo S, Kajimoto T, Tanaka K, Aoyama K, Narita M, Nakamura T. Development of an online neutron beam monitoring system for accelerator-based boron neutron capture therapy in a hospital. Medical physics, 52:605-618, 2025
3. Kashihara T, Nakamura S, Yamazaki N, Takahashi A, Namikawa K, Ogata D, Nakano E, Okuma K, Kaneda T, Mori T, Ito K, Itami J, Shimada K, Nakagama H, Igaki H. Boron neutron capture therapy for cutaneous angiosarcoma and malignant melanoma: First in-human phase I clinical trial. Radiotherapy and oncology, 202:110607, 2025
4. Takahashi K, Kagami Y, Yoshimura R, Morota M, Murakami N, Nakamura S, Okamoto H, Nagao A, Sakuramachi M, Kashihara T, Kaneda T, Inaba K, Okuma K, Nakayama Y, Itami J, Igaki H. Prospective study of once-daily accelerated partial breast irradiation using 3-dimensional conformal external beam radiotherapy for Japanese women: 12-year outcomes, toxicity, and cosmesis. Breast cancer (Tokyo, Japan), 32:197-207, 2025
5. Ozeki Y, Honda-Kitahara M, Yanagisawa S, Takahashi M, Ohno M, Miyakita Y, Kikuchi M, Nakano T, Hosoya T, Sugino H, Satomi K, Yoshida A, Igaki H, Kubo Y, Ichimura K, Suzuki H, Masutomi K, Kondo A, Narita Y. Early progressive disease within 2 years in isocitrate dehydrogenase (IDH)-mutant astrocytoma may indicate radiation necrosis. Japanese journal of clinical oncology, 55:106-112, 2025
6. Imamichi S, Ito T, Tong Y, Gao Z, Arai Y, Fujimori H, Chen L, Sanada Y, Nakamura S, Murakami Y, Ishiai M, Suzuki M, Itami J, Igaki H, Masunaga S, Masutani M. Transcriptome analysis of human oral squamous cancer SAS cells as an early response after boron neutron capture therapy. Applied radiation and isotopes : including data, instrumentation and methods for use in agriculture, industry and medicine, 218:111648, 2025
7. Igaue S, Yamamoto S, Shiraishi K, Itoyama M, Imazeki H, Yokoyama K, Honma Y, Kashihara T, Kurita D, Ishiyama K, Oguma J, Daiko H, Kato K. Correlation Between Histopathological Response of Esophageal Squamous Cell Carcinoma to Neoadjuvant DCF Therapy and the Clinical Efficacy of Palliative Chemotherapy for Recurrence. Journal of gastrointestinal cancer, 56:60, 2025
8. Kobayashi Y, Nakamura S, Takemori M, Nakaichi T, Shuto Y, Ito K, Takahashi K, Kashihara T, Yonemura M, Endo H, Kunito K, Okamoto H, Chiba T, Nakayama H, Oshika R, Kishida H, Itami J, Kurihara H, Igaki H. Comparison of dose distribution with and without reflecting heterogeneous boron distribution using (18)F-BPA positron emission tomography in boron neutron capture therapy. Applied radiation and isotopes : including data, instrumentation and methods for use in agriculture, industry and medicine, 219:111720, 2025
9. Yoshimura RI, Toda K, Watanabe H, Miura M, Notake R, Murakami N, Igaki H, Nakamura S, Umezawa R, Kadoya N, Jingu K, Itami J. Efficacy and safety of diffusing alpha-emitter radiation therapy (DaRT) for head and neck cancer recurrence after radiotherapy. International journal of clinical oncology, 30:893-903, 2025
10. Kashihara T, Nakamura S, Igaki H. Response to 'Pioneering BNCT: Refining strategies for complex cutaneous malignancies. Radiotherapy and oncology, 206:110787, 2025
11. Kawauchi D, Ohno M, Sugino H, Ito K, Fuse K, Yoshida A, Kubo Y, Honda-Kitahara M, Yanagisawa S, Ohmura T, Aoki T, Kawanishi A, Sakuramachi M, Igaki H, Narita Y. Utility of [18F]fluciclovine PET/MRI for identifying the optimal biopsy target region, helping to avoid underdiagnosis in patients with glioblastoma: illustrative case. Journal of neurosurgery. Case lessons, 9:CASE24677, 2025
12. Kurokawa S, Okamoto H, Nakaichi T, Mikasa S, Nakamura S, Iijima K, Chiba T, Nakayama H, Kashihara T, Inaba K, Igaki H. Machine learning prediction for lung dose in locally advanced esophageal cancer using volumetric modulated arc therapy. Medical dosimetry, S0958-3947(25)00011-1, 2025
13. Maebayashi T, Mizowaki T, Ishikawa H, Nakamura K, Inaba K, Asakura H, Iwata H, Itasaka S, Wada H, Sakaguchi M, Jingu K, Akiba T, Tomita N, Nakamura K. Prostate dose escalation may positively impact survival in patients with clinically node-positive prostate cancer definitively treated by radiotherapy: surveillance study of the Japanese Radiation Oncology Study Group (JROSG). Journal of radiation research, 66:157-166, 2025
14. Ono T, Uto M, Mineharu Y, Arakawa Y, Nakamura M, Nishio T, Igaki H, Nihei K, Ishikura S, Narita Y, Mizowaki T. Dummy run study for outlining and plan quality of intensity-modulated radiotherapy in elderly patients with newly diagnosed glioblastoma: The Japan clinical oncology group study JCOG1910 (AgedGlio-PIII). Radiation oncology (London, England), 20:32, 2025
15. Murofushi KN, Tsujino K, Ito Y, Okamoto M, Doi H, Ogawa H, Onozawa M, Kawamoto T, Katoh N, Jingu K, Takeda A, Nihei K, Makishima H, Mayahara H, Yamazaki H, Igaki H. Contouring atlas and essential points for radiotherapy in rectal cancer. Journal of radiation research, 66:203-211, 2025
16. Cho H, Abe S, Nonaka S, Suzuki H, Yoshinaga S, Okuma K, Yamamoto S, Daiko H, Kato K, Sekine S, Boku N, Saito Y. Long-term outcomes after non-curative endoscopic resection for esophageal squamous cell carcinoma followed by additional chemoradiotherapy. Diseases of the esophagus, 37:doae004, 2024
17. Watanabe Y, Chen YW, Igaki H, Arakawa A, Tao K, Sugiyama M, Nakajima M, Shirakawa N, Yanagisawa S, Miyakita Y, Yoshida A, Isohashi K, Ono K, Narita Y, Ogawa C. Boron neutron capture therapy prolongs survival in a patient with a recurrent malignant peripheral nerve sheath tumor-A case report. Pediatric blood & cancer, 71:e31011, 2024
18. Nakamura K, Nihei K, Saito Y, Shikama N, Noda SE, Hara R, Imagumbai T, Mizowaki T, Akiba T, Kunieda E, Someya M, Ohga S, Kawamori J, Kozuka T, Ota Y, Inaba K, Kodaira T, Itoh Y, Funakoshi K, Kagami Y. A Japanese multi-institutional phase II study of moderate hypofractionated intensity-modulated radiotherapy with image-guided technique for prostate cancer. International journal of clinical oncology, 29:847-852, 2024
19. Kashihara T, Urago Y, Okamoto H, Takemori M, Nakayama H, Mikasa S, Nakaichi T, Iijima K, Chiba T, Kuwahara J, Nakamura S, Chang W, Matsui Y, Igaki H. A preliminary study on rectal dose reduction associated with hyaluronic acid implantation in brachytherapy for prostate cancer. Asian journal of urology, 11:286-293, 2024
20. Nakamura S, Takemori M, Nakaichi T, Shuto Y, Kashihara T, Iijima K, Chiba T, Nakayama H, Urago Y, Nishina S, Kobayashi Y, Kishida H, Imamichi S, Takahashi K, Masutani M, Okamoto H, Nishio T, Itami J, Igaki H. A method for delivering the required neutron fluence in an accelerator-based boron neutron capture therapy system employing a lithium target. Scientific reports, 14:11253, 2024
21. Nagao A, Murakami N, Sakuramachi M, Kashihara T, Takahashi K, Kaneda T, Inaba K, Okuma K, Okamoto H, Nakayama Y, Yonemori K, Igaki H. Role of the gel spacer in safely delivering whole pelvic radiation therapy without central shielding in computed tomography-based image-guided adaptive brachytherapy for uterine cervical cancer patients. Brachytherapy, 23:595-603, 2024
22. Okamoto H, Sakuramachi M, Yatsuoka W, Ueno T, Katsura K, Murakami N, Nakamura S, Iijima K, Chiba T, Nakayama H, Shuto Y, Takano Y, Kobayashi Y, Kishida H, Urago Y, Nishitani M, Nishina S, Arai K, Igaki H. A novel method for determining dose distribution on panoramic reconstruction computed tomography images from radiotherapy computed tomography. Imaging science in dentistry, 54:129-137, 2024
23. Okamoto H, Nonaka M, Chiba T, Kaneda T, Kobayashi Y, Nakamura S, Nakayama H, Iijima K, Shuto Y, Yonemura M, Oshika R, Kishida H, Urago Y, Nishitani M, Nishina S, Sakamoto T, Shibata Y, Goka T, Igaki H. Dosimetric impact of the respiratory motion of the liver dome in stereotactic body radiotherapy for spine metastasis: A planning study. Journal of applied clinical medical physics, 25:e14403, 2024
24. Kawaguchi Y, Watanabe Y, Miyakita Y, Ohno M, Ogawa C, Takahashi M, Yanagisawa S, Mukai T, Igaki H, Sugino H, Yoshida A, Narita Y. Successful treatment of pediatric patients with high-grade gliomas featuring leptomeningeal metastases by targeting BRAF V600E mutations with dabrafenib plus trametinib: two illustrative cases. International cancer conference journal, 13:256-262, 2024
25. Uezono H, Onoe T, Shikama N, Ono Y, Hirata H, Ito Y, Yasuda K, Imano N, Kikuchi K, Kashihara T, Kawamoto T, Nakamura N. Uptake of ultra-hypofractionated radiation therapy following breast-conserving surgery among patients with early-stage breast cancer: a multi-institutional questionnaire survey. Breast cancer (Tokyo, Japan), 31:1071-1079, 2024
26. Murata S, Horinouchi H, Morishita M, Kaku S, Shinno Y, Okuma Y, Yoshida T, Goto Y, Yamamoto N, Kashihara T, Okuma K, Kusumoto M, Ohe Y. Impact of Durvalumab on the Duration and Complexity of Corticosteroid Therapy for Pneumonitis After Chemoradiotherapy. Clinical lung cancer, 25:e369-e378.e3, 2024
27. Ohno M, Takahashi M, Yanagisawa S, Osawa S, Tsuchiya T, Fujita S, Igaki H, Narita Y. Development of a scoring system to predict local recurrence in brain metastases following complete resection and observation. Journal of neuro-oncology, 170:297-305, 2024
28. Tsuchiya T, Ohno M, Watanabe Y, Fujita S, Miyazaki B, Sugino H, Igaki H, Yoshida A, Takahashi M, Yanagisawa S, Osawa S, Ogawa C, Narita Y. Pediatric atypical teratoid/rhabdoid tumor in the cauda equina with rapid tumor progression: illustrative case. Journal of neurosurgery. Case lessons, 8:CASE24219, 2024
29. Nakamura S, Tanaka H, Kato T, Akita K, Takemori M, Kasai Y, Kashihara T, Takai Y, Nihei K, Onishi H, Igaki H. A national survey of medical staffs' required capability and workload for accelerator-based boron neutron capture therapy. Journal of radiation research, 65:712-724, 2024
30. Zenda S, Kashihara T, Saito T, Okamoto H, Kadoya N, Chiba T, Noda SE, Kawaguchi T, Jingu K, Shibuya K, Uno T, Igaki H. Two-fractionated stereotactic magnetic resonance-guided adaptive radiation therapy for patients with prostate cancer (SMART PRO trial): protocol for a confirmatory clinical trial. BMJ open, 14:e082899, 2024
31. Iijima K, Nakayama H, Nakamura S, Chiba T, Shuto Y, Urago Y, Nishina S, Kishida H, Kobayashi Y, Takatsu J, Kuwahara J, Aikawa A, Goka T, Kaneda T, Murakami N, Igaki H, Okamoto H. Analysis of human errors in the operation of various treatment planning systems over a 10-year period. Journal of radiation research, 65:603-618, 2024
32. Ohno M, Takahashi M, Yanagisawa S, Osawa S, Tsuchiya T, Fujita S, Igaki H, Narita Y. Correction to: Development of a scoring system to predict local recurrence in brain metastases following complete resection and observation. Journal of neuro-oncology, 170:307, 2024
33. Nishitani M, Okamoto H, Nakamura S, Iijima K, Chiba T, Nakayama H, Nakaichi T, Takemori M, Urago Y, Chang W, Igaki H. A new approach to assess transit dose impact in gynecological and prostate brachytherapy with effective transit time. Journal of contemporary brachytherapy, 16:449-456, 2024