KEIO RESEARCHERS INFORMATION SYSTEM

Research Areas 【 Display / hide 】

Research Areas 【 Display / hide 】

• Life Science / Tumor diagnostics and therapeutics (Radiation Oncology)

Books 【 Display / hide 】

Books 【 Display / hide 】

• Ablative Radiation Therapy for Early Hepatocellular Carcinoma

  Sanuki N., Takeda A., Tsurugai Y., Radiotherapy of Liver Cancer, 2021.01

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  Ablative radiation therapy, also known as stereotactic body radiation therapy (SBRT) or stereotactic ablative body radiotherapy (SABR), has an evolving role in the treatment of hepatocellular carcinoma (HCC), owing to recent advances in technology. SBRT is primarily used when other local therapies are not feasible. Although evidence is limited, SBRT has been demonstrated to be an effective treatment with excellent local control. In this chapter, we discuss the role of SBRT as a curative local therapy for patients with early HCC.

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Papers 【 Display / hide 】

Papers 【 Display / hide 】

• Phase II Study of Dose-Escalated and Convergent Stereotactic Body Radiotherapy for Liver and Pulmonary Oligometastases from Colorectal Cancer

  Nishimura S., Takeda A., Tsurugai Y., Sanuki N., Eriguchi T., Nemoto T.

  Cancers 18 ( 8 )  2026.04

  ISSN  2072-6694

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  Purpose: Surgical resection of liver or pulmonary oligometastases (LP-OMD) in colorectal cancer (CRC) has been shown to improve survival. Stereotactic body radiotherapy (SBRT) is a promising alternative for patients with primary lung cancer. However, the efficacy of SBRT for LP-OMD in CRC remains inconclusive, and local control (LC) rates are often unsatisfactory. This prospective study aimed to evaluate the treatment outcomes of dose-escalated and convergent SBRT for patients with LP-OMD from CRC, with the goal of demonstrating its effectiveness as a treatment option for these patients. Methods and materials: This study included 23 CRC patients with LP-OMD who received SBRT between 2017 and 2022. The inclusion criteria were histologically confirmed colorectal adenocarcinoma, one to three oligometastases, and a tumor diameter of 5 cm or less. Patients who were inoperable or declined surgery were included. SBRT was delivered with total doses of 50–60 Gy administered over five fractions, covering the planning target volume surface within the 60% isodose line of the maximum dose. The primary endpoint was the 2-year LC rate, while secondary endpoints included overall survival (OS), progression-free survival (PFS), and toxicity. Results: The median follow-up duration was 41.0 months (range: 11.5–77.2). At the time of analysis, five patients had died from CRC, six were alive with disease, and twelve were alive without disease. Only one patient experienced local recurrence of a pulmonary oligometastasis. The 2-year LC, PFS, and OS rates were 95.0% (95% CI: 69.5–99.3), 61.3% (95% CI: 40.0–77.0), and 88.1% (95% CI: 67.6–96.0), respectively. Toxicity was acceptable, with no grade ≥ 3 adverse events. Conclusions: High-central-dose SBRT for LP-OMD from CRC achieved favorable local control with minimal toxicity. These findings should be interpreted cautiously and require validation in larger, multi-institutional studies.

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• Feasibility of Tailored Axillary Surgery (TAS) in Patients with Clinically Node-Positive Breast Cancer in the Upfront Surgery Setting: Results of a Prospective, Single-Arm, Multicenter Phase II Trial

  Terata, K; Sagara, Y; Yamamoto, S; Sakai, T; Takayama, S; Kitagawa, D; Ogita, M; Sanuki, N; Yoshida, M; Ueno, T; Nakamura, R; Shigematsu, H; Watanabe, K; Bando, H; Yoshimura, A; Onishi, T; Tokunaga, E; Takahashi, M; Hayashi, T; Nishimura, S; Saimura, M; Matsumoto, H; Harao, M; Yoshiyama, T; Sangai, T; Ohtake, T; Tsuda, H; Hara, F; Fujisawa, T; Iwata, H; Shien, T

  CLINICAL CANCER RESEARCH 32 2026.02

  ISSN  1078-0432

• Postmastectomy radiation therapy for autologous breast reconstruction: a systematic review and meta-analysis for the 2022 Japanese Breast Cancer Society Clinical Practice Guideline

  Ogita M., Sawayanagi S., Jinnouchi H., Yoshimura M., Yamauchi C., Sanuki N., Hamamoto Y., Hirata K., Kawamura M., Yamamoto Y., Saji S., Toyama T.

  Breast Cancer 33 ( 1 ) 1 - 9 2026.01

  ISSN  13406868

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  Background: The safety of postmastectomy radiation therapy (PMRT) after autologous breast reconstruction remains unclear. Therefore, we conducted a systematic review and meta-analysis to investigate the effects of PMRT on patients with breast cancer who underwent autologous breast reconstruction. Methods: A comprehensive literature search of English and Japanese articles until March 2021 was performed using PubMed/MEDLINE, the Cochrane Library, and Ichushi-Web. We included studies that compared the outcomes of patients with breast cancer who underwent immediate autologous breast reconstruction with and without PMRT. Outcomes including major complications, fat necrosis, and cosmetic results were assessed. Pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated using a random effects model. Results: Ten studies (two retrospective case-controlled and eight retrospective cohort studies) comprising 3,123 cases were included. The rate of major complications was slightly higher in the PMRT group compared to the no PMRT group, but the difference was not statistically significant (13.2% vs. 12.2%, OR 1.58, 95% CI 0.93–2.68, P = 0.09). In contrast, the rate of fat necrosis was significantly increased in the PMRT group (17.2% vs. 8.1%, OR 2.71, 95% CI 1.58–4.65, P = 0.0003). Data on cosmetic outcomes were limited and not pooled for the meta-analysis. Conclusions: PMRT following autologous breast reconstruction was associated with a higher risk of fat necrosis, but not with a significantly increased rate of major complications. With careful patient selection and monitoring, PMRT after autologous breast reconstruction can be considered a safe and acceptable treatment option.

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• Annual report of national clinical database-breast cancer registry in 2023: systemic therapy for small breast cancer

  Sasada S., Kumamaru H., Kinukawa N., Iwamoto T., Kawashima M., Konishi T., Saji S., Sanuki N., Tanakura K., Nagahashi M., Miyashita M., Yoshida M., Kinoshita T., Sagara Y., Niikura N., Ishida T., Taira N.

  Breast Cancer  2026

  ISSN  13406868

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  This annual report of the National Clinical Database-Breast Cancer Registry (NCD-BCR) by the Japanese Breast Cancer Society presents nationwide breast cancer statistics for patients registered in Japan in 2023. Among 107,372 patients with breast cancer at 1317 institutions, 99.3% were females with a median age of 62 years. The distribution of the clinical stages was as follows: stage 0 (15.5%); stage I (42.1%); stage II (31.1%); stage III (7.0%); and stage IV (2.1%). Estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 (HER2) positivity was observed in 78.9%, 70.0%, and 13.3% of patients, respectively. Among 102,717 patients without distant metastases, 41.2% underwent breast-conserving surgery, 76.5% underwent sentinel lymph node biopsy, and 6.0% underwent breast reconstruction. The distribution of radiotherapy was as follows: 75.2% received whole-breast irradiation, 15.7% chest-wall irradiation, and 20.7% regional irradiation. Among the 13,061 patients with pT1abN0M0 breast cancer, comprising 10,819 hormone receptor [HR]-positive/HER2-negative, 1479 HER2-positive and 763 HR-negative/HER2-negative individuals, 92.4% of HR-positive/HER2-negative patients received endocrine therapy, 46.9% of HER2-positive patients received chemotherapy and/or anti-HER2 therapy, and 31.2% of HR-negative/HER2-negative patients received chemotherapy. This annual report provides a nationwide overview of contemporary systemic therapy patterns in small breast cancer and highlights size‑dependent and subtype‑specific use of systemic therapy in Japan, reflecting a risk‑adapted treatment strategy.

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• Postmastectomy radiation therapy for implant-based breast reconstruction: a systematic review and meta-analysis for the 2022 Japanese Breast Cancer Society Clinical Practice Guideline

  Ogita M., Sawayanagi S., Jinnouchi H., Yoshimura M., Yamauchi C., Sanuki N., Hamamoto Y., Hirata K., Kawamura M., Yamamoto Y., Saji S., Toyama T.

  Breast Cancer Tokyo Japan 32 ( 6 ) 1169 - 1179 2025.11

  ISSN  1340-6868

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  BACKGROUND: Implant-based breast reconstruction is the most commonly performed reconstructive technique following mastectomy. With an increasing number of patients undergoing implant-based breast reconstruction, concerns have arisen regarding the safety of postmastectomy radiation therapy (PMRT) in reconstructed breasts. This study aimed to investigate the safety of PMRT in implant-based breast reconstruction. METHODS: A comprehensive literature search was conducted for articles published up to March 2021. Eligible studies included clinical trials and observational studies comparing outcomes between patients with breast cancer undergoing immediate implant-based breast reconstruction with PMRT and those without PMRT. The primary outcomes included major complications, reconstruction failure, capsular contracture, and cosmetic outcomes. Pooled odds ratio (OR) with 95% confidence interval (CI) were calculated using a random-effects model. RESULTS: A total of 23 studies were identified, comprising one case-control study, one prospective cohort study, and 21 retrospective cohort studies. PMRT was significantly associated with increased rates of major complications (OR 2.62, 95% CI 1.82-3.77, P < 0.00001), reconstruction failure (OR 2.53, 95% CI 2.00-3.20, P < 0.00001), and capsular contracture (OR 9.63, 95% CI 5.77-16.06, P < 0.00001). Furthermore, cosmetic outcomes were significantly poorer in patients undergoing PMRT compared with those not receiving PMRT (OR 3.55, 95% CI 1.80-6.98, P < 0.003). CONCLUSIONS: This meta-analysis demonstrated that PMRT in implant-based breast reconstruction is associated with a significantly increased risk of adverse outcomes. Given these risks, treatment decisions should involve through discussions with patients to ensure that they are fully informed of the potential benefits and complications.

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Reviews, Commentaries, etc. 【 Display / hide 】

Reviews, Commentaries, etc. 【 Display / hide 】

• Comment on the article titled “Brachial plexopathy following stereotactic body radiation therapy in apical lung malignancies: A dosimetric pooled analysis of individual patient data” by Hui Bai et al

  Sawada M., Takeda A., Sanuki N.

  Radiotherapy and Oncology 217   111197 2026.04

  ISSN  01678140

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• オリゴ転移の局所治療　エビデンスと最新治療戦略(診断)　どのような転移患者が局所治療による恩恵を受けるか?

  武田 篤也, 深田 淳一, 佐貫 直子

  日本医学放射線学会秋季臨床大会抄録集 ((公社)日本医学放射線学会)  61回   S360 - S360 2025.09

  ISSN  0048-0428

• オリゴ転移に対する局所療法　乳癌オリゴ転移に対する局所療法

  佐貫 直子, 根本 貴文, 武田 篤也

  日本乳癌学会総会プログラム抄録集 ((一社)日本乳癌学会)  33回   295 - 295 2025.07

• OPBCS併用乳房温存術後の長期的な全乳房体積の変化　体積に影響を与える因子の検討

  山下 雅子, 野呂 綾, 小島 玲那, 東 千尋, 平子 若菜, 恒川 和弘, 佐貫 直子

  日本乳癌学会総会プログラム抄録集 ((一社)日本乳癌学会)  33回   410 - 410 2025.07

• 高齢者に発症し,放射線治療が奏効した前額部脂腺癌の1例

  水野 彩加, 渡邊 清未, 津田 憲志郎, 小幡 康範, 佐貫 直子, 奈良 佳治

  日本皮膚科学会雑誌 ((公社)日本皮膚科学会)  135 ( 1 ) 128 - 128 2025.01

  ISSN  0021-499X

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Research Projects of Competitive Funds, etc. 【 Display / hide 】

Research Projects of Competitive Funds, etc. 【 Display / hide 】

• Development and application of treatment intensity optimization indicators for personalized radiation therapy for breast cancer in the AYA generation

  2025.07

  -

  2027.03

  研究活動スタート支援, Principal investigator

Courses Taught 【 Display / hide 】

Courses Taught 【 Display / hide 】

• CLINICAL CLERKSHIP IN RADIOLOGY

  2026

• LECTURE SERIES, RADIOLOGY

  2026

• CASE STUDY

  2026

• INTEGRATION OF BASIC SCIENCE AND CLINICAL MEDICINE

  2026

• LECTURE SERIES, RADIOLOGY

  2025