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 】

• 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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• 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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• Timing of postmastectomy radiation therapy in two-stage expander/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 32 ( 6 ) 1159 - 1168 2025.11

  ISSN  13406868

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  Background: In immediate expander/implant reconstruction, postmastectomy radiation therapy (PMRT) can be administered at two different time points: during tissue expander insertion or after exchange with an implant. The optimal timing for PMRT remains unclear. We conducted a systematic review and meta-analysis to evaluate the impact of PMRT timing on the outcomes of patients with breast cancer undergoing two-stage expander/implant breast reconstruction. Methods: A literature review of articles in English and Japanese up to March 2021 was performed using PubMed/MEDLINE, the Cochrane Library, and Ichushi-Web. Studies comparing the timing of PMRT in patients with breast cancer undergoing immediate two-stage expander/implant breast reconstructions and PMRT were included. The assessed outcomes included major complications, reconstruction failure, cosmesis, capsular contractures, and local recurrence. Results: Eleven studies encompassing 1,628 cases were identified. These included one prospective cohort study, one prospective case–control study, and nine retrospective cohort studies. No significant differences were observed in major complications between PMRT to expander and PMRT to implant (odds ratio [OR] 1.11, 95% confidence intervals [CI] 0.72–1.73, P = 0.64). Reconstruction failure was more prevalent in the expander group (OR 2.33, 95% CI 1.43–3.82, P = 0.0007), while severe capsular contractures occurred less frequently in the expander group (OR 0.33, 95% CI 0.12–0.92, P = 0.03). Conclusions: PMRT to expander was associated with higher reconstruction failure and lower severe capsular contracture rates, with no significant differences in major complications by timing. There is insufficient evidence to favor one approach over the other.

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• 【Radiation Therapy Today 2025　定位放射線治療の現状と未来】肝細胞がんに対する体幹部定位放射線治療

  佐貫 直子, 武田 篤也

  INNERVISION ((株)インナービジョン)  40 ( 11 ) 14 - 17 2025.10

  ISSN  0913-8919

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  肝細胞がん(hepatocellular carcinoma:HCC)は,世界的に主要ながん死因の一つであり,日本においても依然として死亡率の高い疾患である。特に,C型肝炎ウイルス(HCV)やB型肝炎ウイルス(HBV)などの感染に伴う肝硬変を背景として発症することが多いが,近年では飲酒や脂肪肝による慢性肝障害もがん化の原因として増加しており,高齢化とともに治療選択の幅の重要性は増加している。HCCの局所治療は,切除,局所療法[ラジオ波焼灼療法(RFA)やマイクロ波凝固療法(MWA)],肝動脈化学塞栓療法(TACE)など多岐にわたるが,これらが非適応の症例に対する治療として,放射線治療(radiotherapy),特に体幹部定位放射線治療(stereotactic body radiation therapy:SBRT)が注目されている。SBRTは,短期間で高線量を腫瘍に集中的に照射する技術であり,非侵襲性と高い制御率が特徴である。本稿では,HCCに対するSBRTの現状とエビデンス,および今後の展望について論じる。(著者抄録)

• Annual report of National Clinical Database-Breast Cancer Registry in 2021: characteristics categorized by body mass index and menopause status

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

  Breast Cancer 32 ( 4 ) 621 - 629 2025.07

  ISSN  13406868

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  The Japanese Breast Cancer Society initiated the breast cancer registry in 1975 and migrated the registry to the National Clinical Database-Breast Cancer Registry (NCD-BCR) in 2012. This annual report presents 2021 data on the NCD-BCR. We analyzed data from 98,540 breast cancer (BC) cases registered in 2021. In 2021, 99.4% of BC cases were females with a median age of 61. Most (57.5%) were diagnosed at early stages (Stage 0 or I). Breast-conserving surgery was performed in 42.8% of cases. Sentinel lymph node biopsy was performed in 67.8%, followed by radiotherapy in 71.0% of those post-conserving surgery. Regarding postoperative systemic therapy, 63.1% received endocrine therapy, 28.2% received chemotherapy, and 14.9% received molecular-targeted therapy. ER positivity was observed in 75.2%, HER2 in 13.6%, and Ki67 ≥30% in 29.1% of cases. The median age of premenopausal cases was 46 (interquartile range, 42–49) years and the median BMI was 21.5 (19.7–24.2) kg/m² whereas the median age of postmenopausal cases was 69 (61–76) years and the median BMI was 23.0 (20.6–25.9) kg/m². In premenopausal cases, cases with normal BMI were more likely to be found at checkups without subjective symptoms and in the early stage than those with high BMI. The tendency of ER, PgR, HER2, and Ki67 status on BMI differed by menopause status; premenopausal cases with a lower BMI showed higher proportions of ER- and PgR-positive cancer and lower proportions of cancer with high Ki67. These nationwide descriptive statistics would help clinical explanation and further research on breast cancer.

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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 】

• LECTURE SERIES, RADIOLOGY

  2025