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Featured researches published by Kotaro Shimizu.


Head and Neck-journal for The Sciences and Specialties of The Head and Neck | 2018

Prognostic role of neutrophil-to-lymphocyte ratio in head and neck cancer: A meta-analysis

Yukinori Takenaka; Ryohei Oya; Takahiro Kitamiura; Naoki Ashida; Kotaro Shimizu; Kazuya Takemura; Yoshifumi Yamamoto; Atsuhiko Uno

Neutrophils play substantial roles in cancer progression. Previous reports demonstrated the prognostic impact of the pretreatment neutrophil‐to‐lymphocyte ratio (NLR) in various types of solid cancers. The purpose of this study was to quantify the prognostic impact of NLR on head and neck squamous cell carcinoma (HNSCC).


PLOS ONE | 2016

Transaminase Activity Predicts Survival in Patients with Head and Neck Cancer.

Yukinori Takenaka; Norihiko Takemoto; Toshimichi Yasui; Yoshifumi Yamamoto; Atsuhiko Uno; Haruka Miyabe; Naoki Ashida; Kotaro Shimizu; Susumu Nakahara; Atshushi Hanamoto; Takahito Fukusumi; Takahiro Michiba; Hironori Cho; Masashi Yamamoto; Hidenori Inohara

Various serum biomarkers have been developed for predicting head and neck squamous cell carcinoma (HNSCC) prognosis. However, none of them have been proven to be clinically significant. A recent study reported that the ratio of aspartate aminotransaminase (AST) to alanine aminotransaminase (ALT) had a prognostic effect on non-metastatic cancers. This study aimed to examine the effect of the AST/ALT ratio on the survival of patients with HNSCC. Clinical data of 356 patients with locoregionally advanced HNSCC were collected. The effect of the AST/ALT ratio on overall survival was analyzed using a Cox proportional hazard model. Moreover, recursive partitioning analysis (RPA) was used to divide the patients into groups on the basis of the clinical stage and AST/ALT ratio. The prognostic ability of this grouping was validated using an independent data set (N = 167). The AST/ALT ratio ranged from 0.42 to 4.30 (median, 1.42) and was a prognostic factor for overall survival that was independent of age, primary sites, and tumor stage (hazard ratio: 1.36, confidence interval: 1.08−1.68, P = 0.010). RPA divided patients with stage IVA into the following two subgroups: high AST/ALT (≥2.3) and low AST/ALT (<2.3) subgroups. The 5-year survival rate for patients with stage III, stage IVA with a low AST/ALT ratio, stage IVA with a high AST/ALT ratio, and stage IVB were 64.8%, 49.2%, 28.6%, and 33.3%, respectively (p < 0.001). Compared with the low AST/ALT group, the adjusted hazard ratio for death was 2.17 for high AST/ALT group (confidence interval: 1.02–.22 P = 0.045). The AST/ALT ratio was demonstrated to be a prognostic factor of HNSCC. The ratio subdivided patients with stage IVA into low- and high-risk groups. Moreover, intensified treatment for the high-risk group may be considered.


Acta Oto-laryngologica | 2016

Risk factors associated with competing mortality among patients with head and neck cancer in Japan.

Yukinori Takenaka; Toshimichi Yasui; Keisuke Enomoto; Haruka Miyabe; Natsue Morizane; Naoki Ashida; Kotaro Shimizu; Masayuki Hirose; Yoshifumi Yamamoto; Atsuhiko Uno

Abstract Conclusions This study demonstrated a high incidence of competing mortality in patients with head and neck cancer (HNC). It identified age to be an independent prognostic factor for non-cancer mortality. These findings contribute to the appropriate treatment selection in clinical settings and study design in clinical trials. Objectives To investigate the incidences of second primary cancer (SPC) and non-cancer mortalities among patients with HNC and reveal the determinant factors for these mortalities. Methods This study reviewed the records of 334 patients with HNC between 2006–2012. The cumulative incidences of HNC, non-cancer, and SPC mortalities were estimated. A Fine and Gray regression model was used to investigate factors associated with cancer and non-cancer mortalities. Results The 5-year cumulative incidences of HNC, SPC, and non-cancer mortalities were 28.0%, 2.5%, and 6.5%, respectively. In univariate analysis, the factors associated with SPC mortality were tumor site and comorbidity, whereas those associated with non-cancer mortality were age, gender, and comorbidity. In multivariate analysis, age (sub-distribution hazard ratio = 2.59) was the independent risk factor for non-cancer mortality.


PLOS ONE | 2017

Prognostic role of neutrophil–lymphocyte ratio in nasopharyngeal carcinoma: A meta-analysis

Yukinori Takenaka; Takahiro Kitamura; Ryohei Oya; Naoki Ashida; Kotaro Shimizu; Kazuya Takemura; Yoshifumi Yamamoto; Atsuhiko Uno

Background Inflammatory markers are used to predict prognosis of nasopharyngeal carcinoma (NPC). Previous reports of neutrophil-to-lymphocyte ratio (NLR) and NPC mortality are inconsistent. This study aimed to quantify the prognostic impact of NLR on NPC. Methods The primary outcome was overall survival (OS), and the secondary outcomes were disease-specific survival (DSS), progression-free survival (PFS) and distant metastasis-free survival (DMFS). We systematically searched electronic databases, identified articles reporting an association between NLR and NPC prognosis. Hazard ratios (HRs) and 95% confidence intervals (CIs) were extracted, and pooled HRs for each outcome were estimated using random effect models. Results Nine studies enrolling 5397 patients were included in the analyses. NLR greater than the cutoff value was associated with poor overall survival (HR 1.51, 95% CI 1.27–1.78), disease-specific survival (HR 1.44, 95% CI 1.22–1.71), progression-free survival (HR 1.53, 95% CI 1.22–1.90), and distant metastasis-free survival (HR 1.83, 95% CI 1.14–2.95). Conclusions Elevated NLR predicts worse OS, DSS, PFS and DMFS in patients with NPC.


Scientific Reports | 2017

Development and validation of a new comorbidity index for patients with head and neck squamous cell carcinoma in Japan

Yukinori Takenaka; Norihiko Takemoto; Ryohei Oya; Naoki Ashida; Takahiro Kitamura; Kotaro Shimizu; Kazuya Takemura; Takahiro Michiba; Atsushi Hanamoto; Motoyuki Suzuki; Yoshifumi Yamamoto; Atsuhiko Uno; Hidenori Inohara

Due to habitual drinking and smoking and advanced age at diagnosis, patients with head and neck squamous cell carcinoma (HNSCC) frequently present with comorbidities. Several comorbidity indices have been developed and validated for HNSCC. However, none have become the standard method. In this study, we developed a new comorbidity index for Japanese patients with HNSCC, which was validated against an independent data set. A Cox proportional hazards analysis of 698 patients identified dementia, connective tissue diseases, and second primary malignancies in the oesophagus, head and neck, lungs, and stomach as prognostic comorbidities for overall survival. The Osaka head and neck comorbidity index (OHNCI) was generated from the weighted points of these comorbidities. In the independent data set, the 5-year overall survival rates for the low, moderate, and high scoring OHNCI groups were 62.1%, 64.3%, and 37.7%, respectively. In the multivariate analysis, the high scoring OHNCI group was an independent prognostic factor for overall survival (hazard ratio: 1.81, 95% confidence interval: 1.05–3.13; P = 0.031). The model including the OHNCI exhibited a higher prognostic capability compared to those including other commonly used comorbidity indices. The OHNCI could become the primary choice for comorbidity assessment in patients with HNSCC in Japan.


Acta Oto-laryngologica | 2017

Age-adjusted Charlson Comorbidity Index predicts prognosis of laryngopharyngeal cancer treated with radiation therapy

Kazuya Takemura; Yukinori Takenaka; Naoki Ashida; Kotaro Shimizu; Ryohei Oya; Takahiro Kitamura; Yoshifumi Yamamoto; Atsuhiko Uno

Abstract Objectives: To examine the ability of comorbidity indices to predict the prognosis of laryngopharyngeal cancer and their association with treatment modalities. Methods: This retrospective study included 198 patients with laryngeal, hypopharyngeal, and oropharyngeal cancers. The effect of comorbidity indices on overall survival between surgery and (chemo)-radiation therapy ((C)RT) groups was analyzed. The cumulative incidence rates for cancer mortality and other mortalities according to the age-adjusted Charlson Comorbidity Index (ACCI) and Charlson Comorbidity Index (CCI) were compared. Results: Univariate survival analyses showed a significant association between the ACCI and overall survival in the (C)RT group, but not in the surgery group. The association between the CCI and overall survival was not significant in either group. In multivariate analyses, a high ACCI score was an independent prognostic factor in the (C)RT group (HR 2.89, 95% confidence interval (CI) 1.28–6.49), but not in the surgery group (HR 1.39, 95%CI 0.27–5.43). The higher ACCI group had increased mortality from other causes compared with the lower ACCI group (5-year cumulative incidence, 8.5% and 17.8%, respectively, p = .003). Conclusion: The ACCI was a better prognostic factor than the CCI. Surgery may be more beneficial than radiation for patients with a high ACCI.


Head and Neck-journal for The Sciences and Specialties of The Head and Neck | 2018

Platelet count and platelet-lymphocyte ratio as prognostic markers for head and neck squamous cell carcinoma: A meta-analysis

Yukinori Takenaka; Ryohei Oya; Takahiro Kitamiura; Naoki Ashida; Kotaro Shimizu; Kazuya Takemura; Yoshifumi Yamamoto; Atsuhiko Uno

Thrombocytosis is associated with the prognosis of various types of cancer. The purpose of this study was to quantify the prognostic impact of platelet count and platelet‐lymphocyte ratio (PLR) in head and neck squamous cell carcinoma (HNSCC).


Otology & Neurotology | 2017

Surgery With or Without Postoperative Radiation Therapy for Early-stage External Auditory Canal Squamous Cell Carcinoma: A Meta-analysis

Ryohei Oya; Yukinori Takenaka; Kazuya Takemura; Naoki Ashida; Kotaro Shimizu; Takahiro Kitamura; Yoshifumi Yamamoto; Atsuhiko Uno


International Journal of Clinical Oncology | 2016

Health insurance status and survival among patients with head and neck cancer in Japan

Yukinori Takenaka; Toshimichi Yasui; Keisuke Enomoto; Haruka Miyabe; Natsue Morizane; Naoki Ashida; Kotaro Shimizu; Masayuki Hirose; Yoshifumi Yamamoto; Atsuhiko Uno


Auris Nasus Larynx | 2017

A case of adult congenital laryngeal cleft asymptomatic until hypopharynx cancer treatment

Kotaro Shimizu; Atsuhiko Uno; Kazuya Takemura; Naoki Ashida; Ryohei Oya; Takahiro Kitamura; Yukinori Takenaka; Yoshifumi Yamamoto

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