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Dive into the research topics where Hiroki Mitani is active.

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Featured researches published by Hiroki Mitani.


Auris Nasus Larynx | 2010

Analysis of 59 cases with free flap thrombosis after reconstructive surgery for head and neck cancer

Seiichi Yoshimoto; Kazuyoshi Kawabata; Hiroki Mitani

OBJECTIVEnThere have been few reports addressing methods of dealing with free flap thrombosis after reconstructive surgery for head and neck cancer. The present study, through a detailed analysis of the subsequent course of patients who developed postoperative flap thrombosis, aims to clarify possible methods of salvage surgery in the event of vascular occlusion despite rigorous postoperative follow-up.nnnMETHODSnWe analyzed 59 cases of postoperative thrombosis in 1031 patients who underwent free flap transfer and considered the most appropriate salvage surgery in the event of total flap necrosis.nnnRESULTSnThe flap salvage rate through vascular reanastomosis was highest for radial forearm flaps, with salvage of jejunal flaps being problematic if postoperative thrombosis occurred. For cases of postoperative thrombosis among patients who underwent reconstruction using a jejunal flap, the period of hospitalization was significantly extended for those patients in whom a second jejunal flap grafting was impossible. For cases of postoperative thrombosis among patients who underwent reconstruction using a radial forearm flap (FA), rectus abdominis flap (RA), or anterior lateral thigh flap (ALT), no significant difference was observed between those undergoing re-grafting with a free flap and those with a pedicled flap.nnnCONCLUSIONnWe concluded that, among patients who undergo reconstruction using a jejunal flap, thrombosis should be discovered at an early stage to enable another jejunal flap re-grafting. For patients who undergo reconstruction using a FA, RA, or ALT, if thrombosis can be discovered at an early stage, there is a possibility of salvaging the flap by means of vascular reanastomosis. If it should prove impossible to salvage the flap, however, primary suture of the defect or reconstruction with a pedicled flap may also be considered.


Pediatric Surgery International | 2005

Acinic cell carcinoma of the parotid gland in a child

Takayuki Sato; Shin-etsu Kamata; Kazuyoshi Kawabata; Tomohiko Nigauri; Hiroki Mitani; Takeshi Beppu; Miki Sato

Acinic cell carcinoma of the parotid gland in children is an extremely rare occurrence. We present a 13-year-old girl with acinic cell carcinoma of the parotid gland. Removal of the superficial lobe of the parotid gland (superficial parotidectomy) was performed because the tumor was completely encapsulated by fibrous tissue and had not invaded the deep parotid gland. There is no clinical evidence of recurrence or metastasis 4xa0years after surgery. In our view, when tumors are completely encapsulated and do not adhere to the facial nerves, superficial parotidectomy is the best surgical treatment in children.


Auris Nasus Larynx | 2010

Factors involved in free flap thrombosis after reconstructive surgery for head and neck cancer.

Seiichi Yoshimoto; Kazuyoshi Kawabata; Hiroki Mitani

OBJECTIVEnReconstructive surgery in which a free flap is used following extended resection for head and neck cancer has been popular for more than a quarter of a century. However, postoperative total flap necrosis has not been completely resolved, and few studies have analyzed the specific risk factors for this complication.nnnMETHODSnOver a three-year period from 2005 to 2007, 388 flaps were used for reconstructive surgery on 384 patients at Department of Head and Neck of the Cancer Institute Hospital of Japanese Foundation for Cancer Research, and the results for 22 flaps with thrombosis were analyzed.nnnRESULTSnThe only statistically significant risk factor for free flap thrombosis was the history of radical concurrent chemoradiotherapy.nnnCONCLUSIONSnIt will be necessary to keep this observation in mind when performing salvage surgery following chemoradiotherapy, which is expected to be performed more often in the future.


Acta Oto-laryngologica | 2007

Treatment results for 84 patients with base of tongue cancer.

Seiichi Yoshimoto; Kazuyoshi Kawabata; Hiroki Mitani; Hiroyuki Yonekawa; Takeshi Beppu; Hirofumi Fukushima; Tohru Sasaki

Conclusions. For T2 tumors, surgery was indicated if functional preservation was possible. For T3/T4 tumors, the rate of primary disease control was not high and surgery frequently involved total laryngectomy. Points that surgeons must heed when performing such surgery were delineated. Objectives. Because tumors originating from the base of the tongue are rare, few large-scale studies of such tumors have been performed. We reviewed treatments and outcomes at our department to establish effective future therapeutic plans. Patients and methods. From 1971 to 2000, 84 patients with previously untreated and resectable squamous cell carcinoma of the base of the tongue were treated at the Head and Neck Department of the Cancer Institute Hospital, Tokyo. Treatment selection and results were investigated. Results. The main treatment options were radiotherapy for primary lesionsu200a≤u200aT2 and surgery for primary lesionsu200a≥u200aT3. Overall disease-specific 5-year cumulative survival rate was 59.8%, but there was no significant difference in survival rate at each stage between the two treatments. Among patients who died of the primary disease, the area that was most difficult to control was the superior margin of the lateral wall of the oropharynx (n=7). The incidence of contralateral or retropharyngeal lymph node metastasis was low if tumors neither crossed the midline nor infiltrated the lateral wall. While total laryngectomy was performed on 48 patients, the larynx was operatively preserved in 5 T3 patients and one T4 patient.


Radiation Medicine | 2008

Malignant mucosal melanoma of the eustachian tube

Hiroko Tanaka; Atsushi Kohno; Naoya Gomi; Kiyoshi Matsueda; Hiroki Mitani; Kazuyoshi Kawabata; Noriko Yamamoto

Malignant mucosal melanoma is a rare condition. Although the head and neck region is the most common site for mucosal melanoma, a melanoma arising in the eustachian tube is rare. Here we present a case of mucosal melanoma arising in the right eustachian tube.


Acta Oto-laryngologica | 2016

Combination chemotherapy of carboplatin and paclitaxel for advanced/metastatic salivary gland carcinoma patients: differences in responses by different pathological diagnoses

Kenji Nakano; Yukiko Sato; Tohru Sasaki; Wataru Shimbashi; Hirofumi Fukushima; Hiroyuki Yonekawa; Hiroki Mitani; Kazuyoshi Kawabata; Shunji Takahashi

Abstract Background: A standard chemotherapy for recurrent/metastatic salivary gland cancers has not been established. Combination chemotherapy of carboplatin and paclitaxel should be evaluated as a treatment option. Methods: This study retrospectively reviewed salivary gland cancer patients who received combination chemotherapy of carboplatin and paclitaxel. The differences in objective responses and in the prognoses according to the different pathological diagnoses were evaluated. Results: A total of 38 patients were enrolled in the study; of them, 18 had salivary duct carcinomas (SDCs), nine had adenoid cystic carcinomas (ACCs), and 11 had other pathological diagnoses. Objective responses were observed in 15 (39%) patients. The median progression-free survival (PFS) was 6.5 months, and the median overall survival (OS) was 26.5 months. ACC patients had relatively low response rates (9%), but there were no significant differences in PFS or OS compared to other sub-types. The treatment was well tolerated, with few adverse events. Conclusion: Salivary gland cancer patients showed a moderate clinical response to the combination chemotherapy of carboplatin and paclitaxel. The objective response rates differed according to the pathological diagnoses, but there were no significant differences in prognoses.


Otolaryngology-Head and Neck Surgery | 2015

A Clinical Study of Pharyngolaryngectomy with Total Esophagectomy: Postoperative Complications, Countermeasures, and Prognoses.

Ryosuke Kamiyama; Hiroki Mitani; Hiroyuki Yonekawa; Hirofumi Fukushima; Toru Sasaki; Wataru Shimbashi; Akira Seto; Yuh Koizumi; Aya Ebina; Kazuyoshi Kawabata

Objective Patients with advanced hypopharyngeal or cervical esophageal cancer have a comparatively high risk of also developing thoracic esophageal cancer. Pharyngolaryngectomy with total esophagectomy is highly invasive, and few reports about it exist. We examined the postoperative complications and respective countermeasures and prognoses of patients who underwent pharyngolaryngectomy with total esophagectomy. Study Design Case series with chart review. Setting Department of Head and Neck Oncology, Cancer Institute Hospital of Japanese Foundation for Cancer Research, Japan. Subjects and Methods We examined the postoperative complications and respective countermeasures and prognoses of 40 patients who underwent pharyngolaryngectomy with total esophagectomy in our hospital. Results Postoperative complications were observed in 23 patients (57.5%) and consisted of 8 groups: tracheal region necrosis in 5 patients; neck abscess formation/wound infection in 5; fistula in 4; tracheostomy suture leakage in 2; ileus in 2; lymphorrhea in 2; pulmonary complications in 2; and other complications, including hemothorax, tracheoinnominate artery fistula, temporary cardiac arrest due to intraoperative mediastinum operation, methicillin-resistant Staphylococcus aureus enteritis, and sepsis, in 1 patient each. A lethal complication—brachiocephalic vein hemorrhage due to tracheostomy suture leakage and hemorrhagic shock due to tracheoinnominate artery fistula—occurred in 2 (5%) patients. The crude 5-year survival rate was 48.6%. Conclusions Serious postoperative complications were related to tracheostomaplasty. Although pharyngolaryngectomy with total esophagectomy is highly invasive, we believe that our outlined treatment method is the most appropriate for cases of advanced hypopharyngeal or cervical esophageal cancer that also requires concurrent surgery for esophageal cancer.


Auris Nasus Larynx | 1999

New classification of stage IV squamous cell carcinoma of the oropharynx

Kazuhiko Yokoshima; Tomohiko Nigauri; Shin-etsu Kamata; Kazuyoshi Kawabata; Katsuhumi Hoki; Hiroki Mitani; Seiichi Yoshimoto

OBJECTIVEnThe recent progress in reconstructive surgery for the treatment of head and neck carcinomas has made it possible to radically resect cancers. However. the choice of treatment for oropharyngeal carcinoma is rather difficult. Radical treatment sometimes results in severe complications, suggesting that some modes of treatment might reduce the quality of life. The 5-year survival rate of patients with stage IV oropharyngeal carcinoma is still very poor. It is necessary to re-classify stage IV squamous cell carcinoma of the oropharynx in relation to the prognosis. Foote et al. (Base of tongue carcinoma: patterns of failure and predictors of recurrence after surgery alone. Head Neck 1993:15:300-307) demonstrated the two subgroups of stage IV oropharyngeal squamous cell carcinoma, as favorable stage IV and unfavorable stage IV. In this study, we have re-examined the validity of these subsets and we have demonstrated the new subsets of stage IV squamous cell carcinoma of the oropharynx.nnnMETHODSnWe have examined 221 cases of oropharyngeal squamous cell carcinoma at the Cancer Institute Hospital in Tokyo between 1971 and 1994. A total of 107 cases of stage IV were included. We analyzed these cases retrospectively.nnnRESULTSnBased on the subsets demonstrated by Foote et al., there were no significant differences between the two groups in our cases, suggesting that these subsets were not useful for the choice of the treatment. In order to make a new classification in view of better choice of treatment, either radical treatment or palliative therapy, these cases were divided into two new groups of stage IV. one group with relatively good results (T1-3 N2 M0 and T4 NO-1 M0; new favorable stage IV), and the other with very poor results (any-T any-N M1 and any-T N3 M0 and T4 N2 M0; new unfavorable stage IV). Patients with the new favorable stage IV have a 5-year survival rate of 30.4%, and those with the new unfavorable stage IV had a survival rate of 0%.nnnCONCLUSIONnThese new subsets of stage IV can be directly related to the prognosis, and are therefore useful in the choice of treatment.


Nippon Jibiinkoka Gakkai Kaiho | 1996

PROGNOSTIC FACTORS OF LATERAL WALL OROPHARYNGEAL SQUAMOUS CELL CARCINOMA

Tomohiko Nigauri; Shin-etsu Kamata; Kazuyoshi Kawabata; Munenaga Nakamizo; Katsufumi Hoki; Hiroki Mitani; Tatsumi Nagahashi; Kazuhiko Yokoshima; Seiichi Yoshimoto

We reviewed 79 patients with squamous cell carcinoma of the lateral wall of the oropharynx who received treatment at the Cancer Institute Hospital. Tokyo, between 1971 and 1990. There were 67 men and 12 women, aged 31 to 81 years (average 59.2 years). The tumors could be staged by TNM classification (UICC 1987) as follows: Stage 10 Stage II 12, Stage III 27, Stage IV 40. It must be noted that more than 50% of the tumors were classified as stage IV. As the initial treatment, 50 patients underwent radical radiotherapy, and the remaining 29 were treated mainly by surgery after pre-operative radiation. Some patients underwent adjuvant chemotherapy, but the role of chemotherapy was not considered in this study. The purpose of the present study was to determine the prognostic factors and to determine the survival rate after each treatment modality. The results were as follows: i) Patients with either T4, over N2b or a stage IV tumor had a significantly poor prognosis. ii) Cox multivariate analysis revealed that age, local extension (base of tongue, anterior pillar, soft palate and mid-line), pathological findings (poorly, moderately or well differentiated), tumor type (exophytic or endophytic) were not useful prognostic factors. iii) Radiosensitivity was not reflected in the survival rate judging from the high recurrence rate (44%) after radical radiotherapy. On the other hand, local recurrence after radical resection was seen in 18% of the patients. iv) Analysis of the data supported the recommendation of surgery after preoperative radiation as the treatment for stage III patients. It seems difficult to find the best treatment modality for stage IV patients in order to improve the survival rate, and this is an issue that still remains to be resolved. v) From the study of the surgical specimens, we are unable to demonstrate a significant survival advantage of the patients with a high grade radiation effect, or patients with no vessel involvement.


Modern Pathology | 2018

MYB and MYBL1 in adenoid cystic carcinoma: diversity in the mode of genomic rearrangement and transcripts

Yuki Togashi; Akito Dobashi; Seiji Sakata; Yukiko Sato; Satoko Baba; Akira Seto; Hiroki Mitani; Kazuyoshi Kawabata; Kengo Takeuchi

MYB-NFIB and MYBL1-NFIB have been reported in ~60% of adenoid cystic carcinoma cases, but driver alterations in the remaining ~40% of adenoid cystic carcinoma remain unclear. We examined 100 adenoid cystic carcinoma cases for MYB and MYBL1 locus rearrangements by fluorescence in situ hybridization (FISH) with originally designed probe sets using formalin-fixed paraffin-embedded materials. Approximately one-third of samples were also analyzed by fusion transcript-specific RT-PCR and capture RNA sequencing. In the 27 cases with frozen materials, MYB-NFIB and MYBL1-NFIB fusion transcripts were detected in 9 (33%) and 6 cases (22%) by RT-PCR, respectively. Meanwhile, high expression of MYB (18 cases, 67%) or MYBL1 (9 cases, 33%) was detected in all 27 cases in a mutually exclusive manner, regardless of its form (full-length, truncation, or fusion transcript). Interestingly, genomic rearrangements around the corresponding highly-expressed gene were observed in all 27 cases by FISH, suggesting a causative relationship between genomic rearrangements and gene expression. Among the 100 cases, including additional 73 cases, 97 harbored genomic rearrangements in the MYB (73 cases) or MYBL1 locus (24 cases) including 10 cases with atypical FISH patterns undetectable through ordinary split FISH approaches: breakpoints far distant from MYB (5 cases) and a small NFIB locus insertion into the MYB (3 cases) or MYBL1 locus (2 cases). In clinicopathological analyses, histological grade, primary tumor size, and lymph node metastasis were identified as prognostic factors, whereas MYB/MYBL1 rearrangements were not, but were associated with histological grade. In the present study, MYB or MYBL1 locus rearrangement was detected in nearly all adenoid cystic carcinoma cases, and therefore it would be a good diagnostic marker for adenoid cystic carcinoma. However, fusion transcript-specific RT-PCR for MYB-NFIB and MYBL1-NFIB and ordinary split FISH assays for MYB and MYBL1 were less sensitive, and thus detection methods should be judiciously designed because of the diversity of rearrangement modes in adenoid cystic carcinoma.

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Kazuyoshi Kawabata

Japanese Foundation for Cancer Research

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Hiroyuki Yonekawa

Japanese Foundation for Cancer Research

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Hirofumi Fukushima

Japanese Foundation for Cancer Research

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Seiichi Yoshimoto

Japanese Foundation for Cancer Research

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Takeshi Beppu

Japanese Foundation for Cancer Research

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Tohru Sasaki

Japanese Foundation for Cancer Research

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Wataru Shimbashi

Japanese Foundation for Cancer Research

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Wataru Shinbashi

Japanese Foundation for Cancer Research

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