Yuta Shibamoto
Nagoya City University
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Featured researches published by Yuta Shibamoto.
Journal of Clinical Oncology | 2000
Branislav Jeremic; Yuta Shibamoto; Biljana Milicic; Nebojsa Nikolic; Aleksandar Dagovic; Jasna Aleksandrovic; Zeljko Vaskovic; Ljiljana Tadic
PURPOSE: To investigate whether the addition of cisplatin (CDDP) to hyperfractionation (Hfx) radiation therapy (RT) offers an advantage over the same Hfx RT given alone in locally advanced (stages III and IV) squamous cell carcinoma of the head and neck. PATIENTS AND METHODS: One hundred thirty patients were randomized to receive either Hfx RT alone to a tumor dose of 77 Gy in 70 fractions in 35 treatment days over 7 weeks (group I, n = 65) or the same Hfx RT and concurrent low-dose (6 mg/m2) daily CDDP (group II, n = 65). RESULTS: Hfx RT/chemotherapy offered significantly higher survival rates than Hfx RT alone (68% v 49% at 2 years and 46% v 25% at 5 years; P = .0075). It also offered higher progression-free survival (46% v 25% at 5 years; P = .0068), higher locoregional progression-free survival (LRPFS) (50% v 36% at 5 years; P = .041), and higher distant metastasis-free survival (DMFS) (86% v 57% at 5 years; P = .0013). However, there was no difference between the two treatment groups in the incidence...
Journal of Clinical Oncology | 1996
Branislav Jeremic; Yuta Shibamoto; Ljubisa Acimovic; Slobodan Milisavljevic
PURPOSE To investigate the efficacy of concurrent hyperfractionated radiation therapy (HFX RT) and low-dose daily chemotherapy (CHT) in stage III non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS Between January 1990 and December 1991, 131 patients with histologically or cytologically confirmed stage III NSCLC, Karnofsky performance status (KPS) > or = 50, and no previous therapy were randomly treated as follows: group I, HFX RT with 1.2 Gy twice daily to a total dose of 69.6 Gy (n = 66); and group II, same HFX RT with CHT consisting of 50 mg of carboplatin (CBDCA) and 50 mg of etoposide (VP-16) given on each RT day (n = 65). RESULTS Group II patients had a significantly longer survival time than group I patients, with a median survival of 22 versus 14 months and 4-year survival rates of 23% versus 9% (P = .021). The median time to local recurrence and 4-year local recurrence-free survival rate were also significantly higher in group II than in group I (25 v 20 months and 42% v 19% respectively, P = .015). In contrast, the distant metastasis-free survival rate did not significantly differ in the two groups (P = .33). The two groups showed similar incidence of acute and late high-grade toxicity (P = .44 and .75, respectively). No treatment-related toxicity was observed. CONCLUSION The combination of HFX RT and low-dose daily CBDCA plus VP-16 was tolerable and improved the survival of patients with stage III NSCLC as a result of improved local control.
Journal of Clinical Oncology | 1995
Branislav Jeremic; Yuta Shibamoto; Ljubisa Acimovic; L Djuric
PURPOSE To investigate the efficacy of combined hyperfractionated radiation therapy (HFX RT) and concurrent chemotherapy (CHT) in stage IIIA or IIIB non-small-cell lung cancer (NSCLC) compared with that of HFX RT alone. PATIENTS AND METHODS Between January 1988 and December 1989, 169 patients were divided randomly into the following groups: group I, HFX RT with 1.2 Gy twice daily to a total dose of 64.8 Gy (n = 61); group II, same HFX RT with CHT consisting of 100 mg of carboplatin (CBDCA) on days 1 and 2 and 100 mg of etoposide (VP-16) on days 1 to 3 of each week during the RT course (n = 52); and group III, same HFX RT with CHT consisting of 200 mg of CBDCA on days 1 and 2 and 100 mg of VP-16 on days 1 to 5 of the first, third, and fifth weeks of the RT course (n = 56). RESULTS The median survival time (MST) was 8 months for group I, 18 months for group II, and 13 months for group III. The 3-year survival rates were 6.6%, 23%, and 16%, respectively. There was a significant difference in the survival rate between groups I and II (P = .0027, log-rank test), but not between groups I and III (P = .17) or between groups II and III (P = .14). The relapse-free survival rate in group II was also higher than that in group I (P = .0024), which was largely due to improved local control in group II patients. Patients in groups II and III showed a higher incidence of acute and/or late high-grade toxicity compared with group I patients, but no patient died of treatment-related toxicity. CONCLUSION The combination of HFX RT and continuous CBDCA/VP-16 CHT was tolerable and substantially increased the survival rate.
Journal of Clinical Oncology | 1997
Branislav Jeremic; Yuta Shibamoto; Ljubisa Acimovic; Slobodan Milisavljevic
PURPOSE To perform a randomized study of the optimal timing of thoracic radiation (RT) as accelerated hyperfractionated radiation therapy (ACC HFX RT) in combination with concurrent chemotherapy (CHT) in limited-stage small-cell lung cancer (SCLC). PATIENTS AND METHODS Between 1988 and 1992, 107 patients were enrolled and 103 were assessable. All patients received ACC HFX RT with 1.5 Gy twice daily to 54 Gy plus concurrent daily carboplatin/etoposide (C/E) (30 mg each) and four sequential cycles of cisplatin/etoposide (PE) (30 mg/m2 and 120 mg/m2, respectively, on days 1 to 3). Group I patients (n = 52) received concurrent chemoradiation at weeks 1 to 4, and group II (n = 51) at weeks 6 to 9. Patients who showed a complete response (CR) or partial response (PR) underwent prophylactic cranial irradiation (PCI) at weeks 16 to 17. RESULTS The median survival time was 34 months in group I and 26 months in group II, and the Kaplan-Meier 5-year survival rates were 30% and 15%, respectively. The difference was almost significant on univariate analysis (P = .052) and was significant on multivariate analysis (P = .027). Group I patients had a significantly higher local control rate than group II patients, but there was no difference between the two groups in distant metastasis rate. There was no difference in the incidence of acute or late grade 3 to 4 toxicity. CONCLUSION Initial administration of thoracic ACC HFX RT with concurrent C/E seems to produce better local control and survival rates than delayed administration.
Radiology | 2009
Mitsuru Takeuchi; Shigeru Sasaki; Masato Ito; Shinsuke Okada; Satoru Takahashi; Tatsuya Kawai; Kaori Suzuki; Hidekazu Oshima; Masaki Hara; Yuta Shibamoto
PURPOSE To prospectively evaluate the ability of diffusion-weighted (DW) magnetic resonance (MR) imaging to be used to determine the T stage of bladder cancer and to measure the correlation between the apparent diffusion coefficient (ADC) and histologic grade. MATERIALS AND METHODS This study was approved by the local institutional review board. All patients gave written informed consent. Forty patients with a total of 52 bladder tumors underwent MR imaging that included DW imaging. Histologic grade was determined for all tumors. Two radiologists interpreted four image sets (ie, T2-weighted images alone, T2-weighted plus DW images, T2-weighted plus dynamic contrast agent-enhanced images, all three image types together). Conventional criteria were used for interpreting T2-weighted and contrast-enhanced images. For DW images, new staging criterion developed on the basis of the hypothesis that tumors, submucosal tissue, and muscles show high, low, and intermediate signal intensity, respectively, was used. The McNemar test was used to examine differences in accuracy, sensitivity, and specificity. Differences in the performance were analyzed by comparing the areas under the receiver operating characteristic curves (A(z) values). To compare ADCs between three histologic grades, analysis of variance was used. RESULTS The overall accuracy of T stage diagnosis was 67% for T2-weighted images alone, 88% for T2-weighted plus DW images, 79% for T2-weighted plus contrast-enhanced images, and 92% for all three image types together. The overall accuracy, specificity, and A(z) for diagnosing T2 or higher stages were significantly improved by adding DW images (P < .01). The mean ADC of G3 tumors was significantly lower than that of G1 and G2 tumors (P < .01). CONCLUSION DW images provided useful information for evaluating the T stage of bladder cancer, particularly in differentiating T1 or lower tumors from T2 or higher tumors. The ADC may in part predict the histologic grade of bladder cancer.
Cancer | 2012
Yuta Shibamoto; Chisa Hashizume; F. Baba; Shiho Ayakawa; Y. Manabe; Aiko Nagai; A. Miyakawa; T. Murai; H. Iwata; Yoshimasa Mori; Mikio Mimura; Satoshi Ishikura
The most common regimen of stereotactic body radiotherapy (SBRT) for stage I nonsmall cell lung cancer in Japan is 48 grays (Gy) in 4 fractions over 4 days. Radiobiologically, however, higher doses are necessary to control larger tumors, and interfraction intervals should be >24 hours to take advantage of reoxygenation. In this study, the authors tested the following regimen: For tumors that measured <1.5 cm, 1.5 to 3.0 cm, and >3.0 cm in greatest dimension, radiation doses of 44 Gy, 48 Gy, and 52 Gy, respectively, were given in 4 fractions with interfraction intervals of ≥3 days.
Radiation Research | 1991
Yuta Shibamoto; Christian Streffer; Claudia Fuhrmann; Volker Budach
An in vivo to in vitro cytokinesis-block micronucleus assay technique using cytochalasin B (Cyt-B) was established in xenografted human and murine tumors, and the correlation between radiosensitivity measured by this assay and that measured by a colony-forming assay was investigated. Tumors were irradiated in situ, excised immediately, and disaggregated to single cells that were plated for the micronucleus and colony-forming assays. Some of the tumor cells were irradiated in vitro rather than in vivo. For the micronucleus assay, Cyt-B (0.5-3 micrograms/ml) was added to dishes soon after plating or in vitro irradiation and the cells were subsequently fixed and stained at intervals (12-144 h). The micronucleus frequency in binucleate cells was evaluated under conditions of maximum yield of the binucleate cells. The micronucleus frequency after irradiation was quite variable depending on the tumor type and the average number of micronuclei per single binucleate cell after 4 Gy ranged from 0.2 to 1.4. The results of in vitro irradiation were not significantly different from those of in vivo irradiation for all tumors. A good correlation was found between the radiosensitivity determined by the micronucleus assay and that found with the colony-forming assay in six human tumors (r = 0.94 approximately 0.98) but not in four murine tumors because of one exceptional tumor. When this tumor was excluded, a correlation was also found for the remaining nine tumors (r = 0.62 approximately 0.96). These results indicated that the cytokinesis-block micronucleus assay has some promise as a rapid predictive assay of radiosensitivity.
Neuro-oncology | 2011
H. Iwata; Kengo Sato; Koshi Tatewaki; Naoki Yokota; M. Inoue; Yoshimi Baba; Yuta Shibamoto
The aim was to evaluate the clinical outcome of hypofractionated stereotactic radiotherapy (SRT) with CyberKnife for nonfunctioning pituitary adenoma. From October 2000 to March 2009, 100 patients with nonfunctioning pituitary adenoma were treated with hypofractionated SRT. Forty-three patients were male, and 57 were female. The patients ages ranged from 16 to 82 years (median, 59 years). Five patients were medically inoperable, and 1 refused surgery; the remaining 94 were recurrent cases or those receiving postoperative adjuvant SRT. No patients had a history of previous cranial radiotherapy. Tumor volume ranged from 0.7 to 64.3 mL (median, 5.1 mL). The marginal doses were 17.0 to 21.0 Gy for the 3-fraction schedule and 22.0 to 25.0 Gy for the 5-fraction schedule. Toxicities were evaluated with the Common Terminology Criteria for Adverse Events version 4.0. The median follow-up period for living patients was 33 months (range, 18-118.5 months). The 3-year overall survival and local control rates were 98% and 98%, respectively. In-field and out-field tumor regrowth were observed in 3 and 2 patients, respectively. Transient cyst enlargement occurred in 3 cases. A post-SRT grade 2 visual disorder occurred in 1 patient. Symptomatic post-SRT hypopituitarism was observed in 3 of 74 patients who had not received hormone replacement therapy after surgery. CyberKnife SRT involving 21 Gy in 3 fractions or 25 Gy in 5 fractions is safe and effective for surgical treatment of nonfunctioning pituitary adenoma. Hypofractionated SRT appears useful for protecting the visual nerve and neuroendocrine function, especially for tumors located near the optic pathways and large tumors.
Cancer | 2010
H. Iwata; Masao Murakami; Yusuke Demizu; D. Miyawaki; Kazuki Terashima; Yasue Niwa; M. Mima; Takashi Akagi; Yoshio Hishikawa; Yuta Shibamoto
A study was undertaken to evaluate the clinical outcome of particle therapy for stage I nonsmall cell lung cancer (NSCLC).
Radiation Oncology | 2010
F. Baba; Yuta Shibamoto; Hiroyuki Ogino; R. Murata; Chikao Sugie; H. Iwata; S. Otsuka; K. Kosaki; Aiko Nagai; T. Murai; A. Miyakawa
BackgroundThe treatment schedules for stereotactic body radiotherapy (SBRT) for lung cancer vary from institution to institution. Several reports have indicated that stage IB patients had worse outcomes than stage IA patients when the same dose was used. We evaluated the clinical outcomes of SBRT for stage I non-small cell lung cancer (NSCLC) treated with different doses depending on tumor diameter.MethodsBetween February 2004 and November 2008, 124 patients with stage I NSCLC underwent SBRT. Total doses of 44, 48, and 52 Gy were administered for tumors with a longest diameter of less than 1.5 cm, 1.5-3 cm, and larger than 3 cm, respectively. All doses were given in 4 fractions.ResultsFor all 124 patients, overall survival was 71%, cause-specific survival was 87%, progression-free survival was 60%, and local control was 80%, at 3 years. The 3-year overall survival was 79% for 85 stage IA patients treated with 48 Gy and 56% for 37 stage IB patients treated with 52 Gy (p = 0.05). At 3 years, cause-specific survival was 91% for the former group and 79% for the latter (p = 0.18), and progression-free survival was 62% versus 54% (p = 0.30). The 3-year local control rate was 81% versus 74% (p = 0.35). The cumulative incidence of grade 2 or 3 radiation pneumonitis was 11% in stage IA patients and 30% in stage IB patients (p = 0.02).ConclusionsThere was no difference in local control between stage IA and IB tumors despite the difference in tumor size. The benefit of increasing the SBRT dose for larger tumors should be investigated further.