Mayanagi, Shuhei



School of Medicine, Department of Surgery (General and Gastroenterological Surgery) (Shinanomachi)



Academic Background 【 Display / hide

  • 2006

    慶應義塾, 医学部


Academic Degrees 【 Display / hide

  • 医学博士, 慶應義塾大学

Licenses and Qualifications 【 Display / hide

  • 日本消化器外科学会専門医

  • 日本外科学会専門医


Research Areas 【 Display / hide

  • Digestive surgery

Research Keywords 【 Display / hide

  • 胃癌

  • 食道癌


Papers 【 Display / hide

  • Perioperative risk calculator for distal gastrectomy predicts overall survival in patients with gastric cancer

    Takeuchi M., Kawakubo H., Mayanagi S., Suzuki Y., Okabayashi K., Yamashita T., Kamiya S., Irino T., Fukuda K., Nakamura R., Suda K., Wada N., Takeuchi H., Kitagawa Y.

    Gastric Cancer (Gastric Cancer)  22 ( 3 ) 624 - 631 2019.05

    ISSN  14363291

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    © 2018, The International Gastric Cancer Association and The Japanese Gastric Cancer Association. Background: Although some predictive factors of long-term survival after a distal gastrectomy for gastric cancer have been reported, only few studies have predicted long-term outcomes based on preoperative parameters. We aimed to evaluate the reliability of perioperative risk calculator for predicting overall survival (OS) after distal gastrectomy in patients with gastric cancer. Methods: Overall, 337 patients (225 males, 112 females) who had undergone a distal gastrectomy for gastric cancer at the Keio University Hospital, Tokyo, Japan, between January 2009 and December 2013 were enrolled in this study. We investigated the reliability of a risk calculator for the prediction of OS. Results: In multivariate analysis, the risk models for operative mortality and 30-day mortality were identified as predictors of death. Time-dependent receiver operating characteristics (ROC) curve analysis indicated that the estimated area under the curve (AUC) value of the risk model for operative mortality was > 0.870 during the first postoperative 3 years. We set optimal cutoff values of the risk model operative mortality for OS using the Cutoff Finder online tool. The cutoff values of 4.117% were significant risk factors of death. Similar results were observed in the external validation set. Conclusions: We elucidated the associations among risk calculator values and OS rates of patients with gastric cancer. Time-dependent ROC curve analysis suggested that the AUC value of the risk model for operative mortality was high, indicating that this risk calculator would be useful for not only short-term outcomes, but also long-term outcomes.

  • Potential for local resection with sentinel node basin dissection for early gastric cancer based on the distribution of primary sites

    Aoyama J., Kawakubo H., Goto O., Nakahara T., Mayanagi S., Fukuda K., Suda K., Nakamura R., Wada N., Takeuchi H., Kitagawa Y.

    Gastric Cancer (Gastric Cancer)  22 ( 2 ) 386 - 391 2019.03

    ISSN  14363291

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    © 2018, The International Gastric Cancer Association and The Japanese Gastric Cancer Association. Background: Based on the sentinel node (SN) concept, function-preserving surgery with SN basin dissection (SNBD) can be performed for SN-negative early gastric cancers. Particularly, a resection area can be minimized when the SN basin and primary site are closely localized. The aim of this study was to compare probabilities of being candidates for local resection with SNBD based on tumor location among patients with early gastric cancer. Methods: We retrospectively analyzed 358 patients who underwent surgery with SN mapping for gastric cancer in our institution from November 1999 to April 2014. The proportion of patients who had a localized single basin and the distributions of the SN basins and primary sites were investigated. Patients with single basin drainage excluding remote sentinel node basin were considered as candidates for local resection with SNBD. Results: Of the 358 patients, 191 (53%) patients were considered eligible for local resection with SNBD. Patients with tumors located in the upper third of the stomach were more likely candidates for local resection than those with tumors in other locations (upper third, 68%; middle third, 50%; and lower third, 51%), whereas patients with tumors located in the anterior wall were less likely candidates than those with tumors other locations (anterior wall, 31%; posterior wall, 58%; greater curvature, 55%; and lesser curvature, 57%). Conclusion: We found that > 50% of the patients indicated for SN navigation surgery, particularly those with tumors in the upper third of the stomach, potentially could undergo partial resection with SNBD.

  • Analysis of the Effect of Early Versus Conventional Nasogastric Tube Removal on Postoperative Complications After Transthoracic Esophagectomy: A Single-Center, Randomized Controlled Trial

    Hayashi M., Kawakubo H., Shoji Y., Mayanagi S., Nakamura R., Suda K., Wada N., Takeuchi H., Kitagawa Y.

    World Journal of Surgery (World Journal of Surgery)  43 ( 2 ) 580 - 589 2019.02

    ISSN  03642313

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    © 2018, Société Internationale de Chirurgie. Background: Although esophagectomy is the only curative option for esophageal cancer, the associated invasiveness is high. Nasogastric (NG) tube use may prevent complications; however, its utility remains unclear, and the decompression period depends on the doctor. This study aimed to reveal the effect of conventional versus early NG tube removal on postoperative complications after esophagectomy. Methods: This single-center prospective randomized controlled clinical trial enrolled patients aged 20–80 years with histologically proven primary esophageal squamous cell carcinoma. Eighty patients admitted for transthoracic first-stage esophagectomy reconstructed with gastric conduit were randomly assigned (1:1) to the conventional and early NG tube removal groups. In the conventional NG tube removal group, the tube was removed on postoperative day (POD) 7; in the other, it was removed on POD 1. The occurrence rate of major complications, length of postoperative hospital stay, and NG tube reinsertion rate were compared between the groups. Results: The incidence of postoperative major complications such as pneumonia, anastomotic leakage, recurrent nerve palsy and gastrointestinal bleeding, and the NG tube reinsertion rate was not different between the groups. However, recurrent nerve palsy was more commonly observed in the conventional removal group; this difference was not significant. In terms of postoperative pneumonia, tumor location and field of lymph node dissection were significant risk factors. Conclusion: Although early NG tube removal did not reduce the rate of postoperative pneumonia, it could be performed safely. Hence, the NG tube can be removed earlier than conventional methods.

  • Risk of lymph node metastasis in undifferentiated-type mucosal gastric carcinoma

    Nakamura R., Omori T., Mayanagi S., Irino T., Wada N., Kawakubo H., Kameyama K., Kitagawa Y.

    World Journal of Surgical Oncology (World Journal of Surgical Oncology)  17 ( 1 )  2019.02

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    © 2019 The Author(s). Background: Endoscopic resection (ER) has come to be recognized as a standard treatment for early gastric cancer (EGC). While its adoption is expanding, ER remains restricted to cases of EGC without lymph node metastasis for the treatment of local resection. On the other hand, histopathological analyses of surgically resected specimens of EGC have revealed the presence of lymph node (LN) metastasis in some cases of mucosal gastric cancer (MGC) and undifferentiated MGC (UD-MGC) is considered to have higher risk of nodal metastases than differentiated MGC (D-MGC). To evaluate the risk factors for LN metastasis in MGC, we investigated the characteristics of UD-MGC associated with LN metastasis. Methods: Among all UD-MGC patients who underwent surgery as initial treatment, between January 2000 and March 2016, we reviewed the clinicopathological data, including the preoperative endoscopic findings and histopathological findings in the resected specimens, of the 11 UD-MGC patients who were identified as having lymph node metastasis. Furthermore, in comparison with cases without lymph node metastasis, we examined the possibility of expansion of the indication for local treatment. Results: In most of the cases of UD-MGC with LN metastasis, the lesions were relatively large (> 20 mm in diameter) and of the clearly depressed type with faded color and apparent border, and histopathology revealed a high percentage of cases with lymphatic invasion and a predominance of signet ring cell carcinomas. No cases with LN metastasis without depressed macroscopic type nor signet ring cell carcinoma component existed. A degree of invasion of lamina propria (LP) or muscularis mucosae (MM) had same relation to the risk of LN metastasis. Conclusions: In this study, none of the cases of undifferentiated-type mucosal cancer (UD-MGC) with LN metastasis satisfied the current adoption criteria for ER. We suggested significant risk factors for LN metastasis in UD-MGC cases as depressed tumor type, presence of a signet ring cell carcinoma component, presence of lymphatic tumor invasion, and a large tumor size. More detailed analyses of the endoscopic and histopathological findings may allow further risk classification for LN metastasis in cases of UD-MGC.

  • Risk factors for lymph node metastasis in non-sentinel node basins in early gastric cancer: sentinel node concept

    Takeuchi M., Takeuchi H., Kawakubo H., Shimada A., Nakahara T., Mayanagi S., Niihara M., Fukuda K., Nakamura R., Suda K., Wada N., Kitagawa Y.

    Gastric Cancer (Gastric Cancer)  22 ( 1 ) 223 - 230 2019.01

    ISSN  14363291

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    © 2018, The International Gastric Cancer Association and The Japanese Gastric Cancer Association. Background: Sentinel node (SN) concept is being applied to early gastric cancer. However, when SNs are positive for metastasis, it is unclear how often LNs in other LN basins show metastasis. We aimed to investigate LN metastasis possibility in LN basins without SNs (non-SN basins). We determined risk factors for metastasis in non-SN basins and identified a prediction model for non-SN basin metastasis using classification and regression tree (CART) analysis. Methods: We enrolled 550 patients who were diagnosed with cT1N0M0 or cT2N0M0 gastric cancer with a single lesion and underwent SN mapping. We adopted a dual-tracer method using a radioactive colloid and blue dye to detect SNs. Results: Of all, 45 (8.2%) patients had SN metastasis; we divided them into two groups: LN metastasis positive and LN metastasis negative in non-SN basins. Univariate analysis showed that the groups differed significantly regarding lymphatic invasion (p = 0.007), number of identified SNs (p = 0.032), and macrometastasis in SN basins (p = 0.005). The CART decision tree for predicting LN metastasis in non-SN basins had area under the curve value of 0.86. Moreover, there were significantly differences in cancer-specific survival (CSS) between the two groups (p = 0.028). Conclusions: Macrometastasis in SN basins, lymphatic invasion, and number of identified SNs ≥ 5 are risk factors for LN metastasis in non-SN basins among gastric cancer patients. We identified a prediction model with CART analysis; patients with macrometastasis in SN basins and lymphatic invasion were considered to be at the highest risk for LN metastasis.

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

  • 食道がん術後サルコペニア予防の為の栄養・運動療法による介入臨床試験


    MEXT,JSPS, Grant-in-Aid for Scientific Research, 真柳 修平, Grant-in-Aid for Early-Career Scientists , Principal Investigator