Masuda, Kenta

写真a

Affiliation

School of Medicine, Department of Obstetrics and Gynecology (Gynecology) ( Shinanomachi )

Position

Assistant Professor/Senior Assistant Professor
 

Books 【 Display / hide 】

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Papers 【 Display / hide 】

  • Japanese society for cancer of the colon and rectum (JSCCR) guidelines 2024 for the clinical practice of hereditary colorectal cancer.

    Tanakaya K, Yamaguchi T, Hirata K, Yamada M, Kumamoto K, Akiyama Y, Ishimaru K, Okamoto K, Kawasaki Y, Komine K, Sakamoto A, Shigeyasu K, Shibata Y, Shimamoto Y, Shimodaira H, Sekine S, Takao A, Takao M, Takamizawa Y, Takeuchi Y, Tanabe N, Taniguchi F, Chino A, Cho H, Doi S, Nakajima T, Nakamori S, Nakayama Y, Nagasaki T, Hasumi H, Banno K, Hinoi T, Fujiyoshi K, Horimatsu T, Masuda K, Miguchi M, Mizuuchi Y, Miyakura Y, Mutoh M, Yoshioka T, Tanaka S, Sakamoto K, Sakamaki K, Itabashi M, Ishida H, Tomita N, Sugihara K, Ajioka Y, Japanese Society for Cancer of the Colon, Rectum

    International journal of clinical oncology  2025.11

    ISSN  1341-9625

    　View Summary

    Approximately 5% of all colorectal cancers have a strong genetic component and are classified as hereditary colorectal cancer (HCRC). Some of the unique features commonly seen in HCRC cases include early age of onset, synchronous/metachronous cancer occurrence, and multiple cancers in other organs. These characteristics require different management approaches, including diagnosis, treatment or surveillance, from those used in the management of sporadic colorectal cancer. Accurate diagnosis of HCRC is essential because it enables targeted surveillance and risk reduction strategies that improve patient outcomes. Recent genetic advances revealed several causative genes for polyposis and non-polyposis syndromes. The Japanese Society for Cancer of the Colon and Rectum (JSCCR) first published guidelines for the management of HCRC in 2012, with subsequent revisions every 4 years. The 2024 update to the JSCCR guidelines for HCRC was developed by meticulously reviewing evidence from systematic reviews and the consensus of the JSCCR HCRC Guidelines Committee, which includes representatives from patient advocacy groups for FAP and Lynch syndrome. These guidelines provide an up-to-date summary of HCRC, along with clinical recommendations for managing FAP and Lynch syndrome.

  • Current Situation and Future Directions of Risk-reducing Salpingo-oophorectomy.

    Kenta Masuda, Yusuke Kobayashi, Tomoko Seki, Tomoko Yoshihama, Kohei Nakamura, Yumiko Goto, Mamiko Yamada, Aiko Nagayama, Sayaka Uchida, Ikumi Ono, Kumiko Misu, Megumi Yokota, Wataru Yamagami

    The Keio journal of medicine 74 ( 3 ) 138 - 145 2025.09

    Lead author, Corresponding author, Accepted,  ISSN  0022-9717

    　View Summary

    High-grade serous carcinoma (HGSC), the most aggressive subtype of epithelial ovarian cancer, is strongly associated with hereditary breast and ovarian cancer (HBOC) syndrome and is primarily linked to germline BRCA1/2 pathogenic variants (PVs). The cumulative risks of ovarian cancer by the age of 70 years are 40% and 18% for carriers of BRCA1 and BRCA2 PVs, respectively. Risk-reducing salpingo-oophorectomy (RRSO) is a recommended preventive strategy that reduces the risk of ovarian cancer by more than 80% and may improve overall survival. However, surgical menopause after RRSO poses several challenges, including infertility and hormonal deficiency. Although the use of hormone replacement therapy may alleviate symptoms, it requires careful consideration of breast cancer risk. Emerging strategies, such as prophylactic salpingectomy with delayed oophorectomy, are being investigated to balance cancer prevention and patient quality of life. Further research is required to refine personalized prevention and management approaches for HBOC-associated ovarian cancer.

  • The Keio HBOC Center: A Model of Hereditary Breast and Ovarian Cancer Management.

    Yusuke Kobayashi, Kenta Masuda, Tomoko Seki, Takeo Kosaka, Minoru Kitago, Ikumi Ono, Kumiko Misu, Arisa Ueki, Tomoko Yoshihama, Aiko Nagayama, Yota Yasumizu, Yumiko Goto, Kohei Nakamura, Mamiko Yamada, Megumi Yokota, Sayaka Uchida, Mari Takeuchi, Takeru Funakoshi, Wataru Yamagami

    The Keio journal of medicine 74 ( 3 ) 124 - 129 2025.09

    ISSN  0022-9717

    　View Summary

    The management of hereditary breast and ovarian cancer (HBOC) in Japan has changed drastically with the expansion of indications for poly ADP-ribose polymerase inhibitors, the increase in diagnostic opportunities with the spread of companion diagnoses, and partial insurance coverage of HBOC management. These circumstances require a response that is coordinated across the entire hospital rather than from individual departments. In April 2021, we established the HBOC Center, which is operated by nine departments: Obstetrics and Gynecology, Reproduction, Surgery (breast group, hepato-pancreato-biliary group), Urology, Dermatology, Neuropsychiatry, the Center for Medical Genetics, and the Cancer Center. In addition to discussions of individual cases, our monthly conferences have enabled us to establish indication criteria and appropriate items for surveillance, visualize the examination flow in the hospital, construct a patient database, and provide open lectures to educate the public. The future HBOC management system should not only fulfill the existing requirements for risk-reducing surgery and facility standards but also offer comprehensive and diversified attention based on the needs of patients and their family members.

  • Pancreatic Cancer in Hereditary Breast and Ovarian Cancer Syndrome: Is Early Detection Possible?

    Kodai Abe, Minoru Kitago, Yusuke Kobayashi, Kenta Masuda, Tomoko Seki, Mamiko Yamada, Yumiko Goto, Ikumi Ono, Kumiko Misu, Kohei Nakamura, Yuko Kitagawa

    The Keio journal of medicine 74 ( 3 ) 146 - 150 2025.09

    ISSN  0022-9717

    　View Summary

    A program of recruiting families with hereditary pancreatic cancer and hereditary breast and ovarian cancer (HBOC) syndrome as high-risk individuals for pancreatic cancer surveillance using magnetic resonance cholangiopancreatography (MRCP) and endoscopic ultrasound (EUS) has proven effective, resulting in the improvement of early detection rates and life expectancy. Given this, recent guidelines recommend pancreatic surveillance for patients with familial pancreatic cancer and pathological variants of ten genes, including BRCA1/2. In April 2021, our hospital established the HBOC Center, which is operated by nine departments, including obstetrics and gynecology, breast surgery, pancreatology, urology, medical genetics, dermatology, psychiatry and neurology, and oncology. Currently, MRCP or EUS is performed once or twice a year in 63 cases with pathogenic variants in 54 families. Although 4 cases (6.3%) revealed pancreatic microcysts or branched intraductal papillary mucinous neoplasms, no sign of pancreatic cancer was detected. Since January 2021, the germline BRCA1/2 test for companion diagnosis of pancreatic cancer has been covered by insurance, improving the accessibility of genetic testing among patients with pancreatic cancer. However, the BRCA1/2 positivity rate remains low at 1.3%, and its indication for use is very limited. The implementation of genetic testing, including BRCA1/2 analysis, is necessary for the prevention and early detection of pancreatic cancer in high-risk families.

  • Exploring Breast Cancer Risk Management in HBOC Patients: Image Surveillance Versus Risk-reducing Surgery.

    Tomoko Seki, Yusuke Kobayashi, Kenta Masuda, Kohei Nakamura, Mamiko Yamada, Yumiko Goto, Kumiko Misu, Ikumi Ono, Aiko Nagayama, Tetsu Hayashida, Yuko Kitagawa

    The Keio journal of medicine 74 ( 3 ) 130 - 137 2025.09

    ISSN  0022-9717

    　View Summary

    In Japan, the rising incidence of hereditary breast and ovarian cancer syndrome (HBOC) follows partial insurance coverage introduced in 2020. Compared with the general population (~11% lifetime risk), individuals with HBOC face a significantly higher lifetime risk of breast cancer (48%-76%), often presenting at younger ages. BRCA1 mutations are linked to triple-negative breast cancer, whereas BRCA2 mutations typically result in luminal-type disease. Key risk management strategies include surveillance and prophylactic surgery. Annual magnetic resonance imaging and mammography are recommended at younger ages than in the general population, despite concerns regarding contrast agents, radiation exposure, and examination-related burdens. Although risk-reducing mastectomy lowers breast cancer risk by over 90%, it remains underutilized because of cosmetic and psychological considerations. Nipple-sparing or skin-sparing mastectomy combined with immediate or delayed reconstruction offers a balance between risk reduction and postoperative outcomes, although safety and procedure details still warrant careful evaluation. Managing the high breast cancer risk associated with HBOC requires ongoing efforts to refine current strategies while minimizing patient burden.

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Papers, etc., Registered in KOARA 【 Display / hide 】

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Reviews, Commentaries, etc. 【 Display / hide 】

  • 【前立腺癌診療における診療連携】遺伝子診療部との連携　遺伝医療における連携

    増田 健太

    Prostate Journal (医学図書出版(株))  11 ( 1 ) 96 - 101 2024.04

    ISSN  2188-4978

    　View Summary

    BRCA遺伝子検査やがんゲノムプロファイル検査などの遺伝子検査は,現在のがん治療において不可欠である。コンパニオン診断として行われる場合,がん治療を担当する主治医が検査に対応するが,その結果としてHBOCが診断される可能性がある。遺伝情報の取り扱いや家系員へのアプローチは主治医も把握すべき重要なポイントであり,適切な遺伝医療を提供するためには遺伝診療部との緊密な連携が不可欠である。(著者抄録)

  • Serous Tubal Intraepithelial Carcinoma (STIC) and Precancerous Lesions in Risk-Reducing Salpingo-oophorectomy (RRSO) Specimens

    Kenta Masuda, Daisuke Aoki

    Practical Guide to Hereditary Breast and Ovarian Cancer (Springer Nature Singapore)     33 - 45 2023.11

    Lead author, Corresponding author

    　View Summary

    Risk-reducing salpingo-oophorectomy (RRSO) is recommended for women with a BRCA1 or BRCA2 (BRCA1/2) pathogenic variant because there is no effective surveillance method for ovarian cancer. RRSO has been shown to not only reduce the risk of developing ovarian cancer but also to reduce cancer mortality. It is known that a certain percentage of occult cancer that could not be diagnosed preoperatively, an early cancer lesion called serous tubal intraepithelial carcinoma (STIC), or precancerous lesions called serous tubal intraepithelial lesion (STIL) and p53 signature are seen in fallopian tubes and ovaries. However, the clinical significance of STIC, STIL, and p53 signature is not well established. In this chapter, we summarize the reports about these lesions found in RRSO specimens with the aim of helping clinical management and future research.

  • 当科における悪性腫瘍治療後患者へのホルモン補充療法(HRT)の有用性に関する検討

    谷本 慧子, 横田 めぐみ, 椎名 美希, 大野 あゆみ, 黒田 由香, 吉浜 智子, 千代田 達幸, 増田 健太, 西尾 浩, 仲村 勝, 山上 亘, 弟子丸 亮太, 岩田 卓, 阪埜 浩司, 青木 大輔

    日本女性医学学会雑誌 ((一社)日本女性医学学会)  29 ( 1 ) 114 - 114 2021.10

    ISSN  2185-8861

  • がん遺伝子パネル検査を通した子宮体癌におけるBRCAバリアント頻度の検討

    今枝 慶蓉, 小林 佑介, 増田 健太, 中村 康平, 四十物 絵理子, 植木 有紗, 千代田 達幸, 山上 亘, 阪埜 浩司, 西原 広史, 田中 守, 青木 大輔

    関東連合産科婦人科学会誌 ((一社)関東連合産科婦人科学会)  58 ( 3 ) 407 - 407 2021.10

    ISSN  2186-0610

  • 人工知能を用いたCIN2の予後予測システムの開発のための予備的検討

    高橋 孝幸, 小林 佑介, 安康 真由香, 野上 侑哉, 辻 浩介, 増田 健太, 岩田 卓, 冨永 英一郎, 田宮 元, 阪埜 浩司, 田中 守, 青木 大輔

    日本産科婦人科学会雑誌 ((公社)日本産科婦人科学会)  73 ( 臨増 ) S - 391 2021.03

    ISSN  0300-9165

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

  • 卵管オルガノドを駆使した卵巣癌早期発見マーカー、癌予防薬の同定

    2023.09
    -
    2029.03

    国際共同研究加速基金（海外連携研究）, Principal investigator

  • 卵巣癌の微小残存病変における腫瘍免疫微小環境の解明

    2023.04
    -
    2026.03

    基盤研究(C), Principal investigator

  • 卵巣癌の微小残存病変に対する解析研究

    2020.04
    -
    2023.03

    MEXT,JSPS, Grant-in-Aid for Scientific Research, Grant-in-Aid for Early-Career Scientists , Principal investigator

    　View Summary

    卵巣癌、特に漿液性癌は、化学療法に対する寛解率が高いものの、その後高確率で再発に至る。その事実は、化学療法後に微小残存病変が存在し、卵巣癌再発の直接的な要因となっていることを示唆している。しかしながら卵巣癌微小残存病変に対する解析方法は確立されておらず、有効な治療法はない。
    本研究では、卵巣癌再発の直接的原因である微小残存病変を治療標的とした”真の精密医療”を実現するため、化学療法前後の臨床検体を用いた網羅的遺伝子発現解析を行い、さらに卵巣癌の微小残存病変を模倣したin vitroモデルを開発を試み、新たな治療戦略を立案するための基礎データを得る。

  • 卵巣癌微小残存病変に対する癌-微小環境の相互作用に着目した新規治療法の開発

    2020.04
    -
    2021.03

    慶應義塾大学, 学事振興資金(個人研究), Principal investigator

  • 卵巣癌微小残存病変に対するシングルセル解析技術を用いた新規治療戦略の開発

    2020.04
    -
    2021.03

    慶應義塾大学医学研究助成, 坂口光洋記念慶應義塾医学振興基金, Principal investigator

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Courses Taught 【 Display / hide 】

  • LECTURE SERIES, GYNECOLOGY

    2025

  • ESSENTIAL CLINICAL GENETICS AND GENOMICS IN NURSING

    2025

  • LECTURE SERIES, GYNECOLOGY

    2024

  • LECTURE SERIES, GYNECOLOGY

    2023

  • LECTURE SERIES, GYNECOLOGY

    2022

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