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Dive into the research topics where Hiroki Ishibashi is active.

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Featured researches published by Hiroki Ishibashi.


Cancer Chemotherapy and Pharmacology | 2017

Is there any predictor for hypersensitivity reactions in gynecologic cancer patients treated with paclitaxel-based therapy?

Tadashi Aoyama; Masashi Takano; Morikazu Miyamoto; Tomoyuki Yoshikawa; Hiroaki Soyama; Kento Kato; Hiroki Ishibashi; Hideki Iwahashi; Masaya Nakatsuka; Isao Yajima; Yukihiro Shimizu; Yusuke Aizawa; Yuki Suguchi; Miki Moriiwa; Tomoko Goto; Hidenori Sasa; Isao Nagaoka; Hitoshi Tsuda; Kenichi Furuya

PurposeRecently, generic drugs of paclitaxel have been commonly used mainly by economic reasons; however, predictive factors for toxicities are not fully determined. Hypersensitivity reaction (HSR) is one of the most important adverse events in the paclitaxel-based therapy, and sometimes leads to lethal condition. The aim of the study was to identify predictors for HSR in patients treated with paclitaxel-based regimens.MethodsAll the patients treated with chemotherapy including paclitaxel at our hospital between 1998 and 2013 were retrospectively evaluated. Clinicopathological factors of the patients that developed HSR and those without HSR were compared, and predictive factors for HSR were identified.ResultsAmong 414 patients enrolled in the study, 26 patients (6.3%) developed HSR. Multivariate analyses showed that younger age (odds ratio 6.31), a history of allergy (odds ratio 3.79), and short-course premedication (odds ratio 14.1) were identified as predictive factors for HSR. There was no significant difference in the incidence of HSR between original paclitaxel and generic drug. The incidence of HSR was higher as the number of these predictors was accumulated.ConclusionsThree factors were identified as predictive factors for HSR: younger age, a history of allergy, and short-course premedication. Accumulation of these factors increased the incidence of HSR; however, the use of generic drug was not associated HSR in gynecologic cancer patients.


Taiwanese Journal of Obstetrics & Gynecology | 2017

Pregnancy with asymptomatic uterine complete rupture after uterine artery embolization for postpartum hemorrhage

Hiroaki Soyama; Morikazu Miyamoto; Hidenori Sasa; Hiroki Ishibashi; Masashi Takano; Kenichi Furuya

OBJECTIVE Uterine artery embolization has become an effective treatment for postpartum hemorrhage. The safety of pregnancy after uterine artery embolization for postpartum hemorrhage has been established. CASE REPORT We present the case of a pregnant woman with asymptomatic uterine complete rupture who underwent uterine artery embolization for a previous placenta previa. She had not been diagnosed with uterine rupture until cesarean section was performed, and fortunately, we obtained the best maternal and neonatal outcomes. CONCLUSION Many studies have been reported that uterine artery embolization for postpartum hemorrhage did not affect subsequent pregnancy outcomes. However, we report that this procedure contains a potential risk for asymptomatic uterine rupture in a subsequent pregnancy. Although it is difficult to diagnose uterine rupture without symptoms, the obstetrician should be aware of the possibility of uterine rupture.


Archives of Gynecology and Obstetrics | 2017

Cervical varicosities may predict placenta accreta in posterior placenta previa: a magnetic resonance imaging study

Hiroki Ishibashi; Morikazu Miyamoto; Hiroshi Shinnmoto; Wakana Murakami; Hiroaki Soyama; Masaya Nakatsuka; Takahiro Natsuyama; Masashi Yoshida; Masashi Takano; Kenichi Furuya

PurposeThe aim of this study was to prenatally predict placenta accreta in posterior placenta previa using magnetic resonance imaging (MRI).MethodsThis retrospective study was approved by the Institutional Review Board of our hospital. We identified 81 patients with singleton pregnancy who had undergone cesarean section due to posterior placenta previa at our hospital between January 2012 and December 2016. We calculated the sensitivity and specificity of several well-known findings, and of cervical varicosities quantified using magnetic resonance imaging, in predicting placenta accreta in posterior placenta previa. To quantify cervical varicosities, we calculated the A/B ratio, where “A” was the minimum distance from the most dorsal cervical varicosity to the deciduous placenta, and “B” was the minimum distance from the most dorsal cervical varicosity to the amniotic placenta. The appropriate cut-off value of the A/B ratio was determined using a receiver operating characteristic (ROC) curve.ResultsThree patients (3.7%) were diagnosed as having placenta accreta. The sensitivity and specificity of the well-known findings were 0 and 97.4%, respectively. Furthermore, the A/B ratio ranged from 0.02 to 0.79. ROC curve analysis revealed that the area under the combined placenta accreta and A/B ratio curve was 0.96. When the cutoff value of the A/B ratio was set 0.18, the sensitivity and specificity were 100 and 91%, respectively.ConclusionIt was difficult to diagnose placenta accreta in the posterior placenta previa using the well-known findings. The quantification of cervical varicosities could effectively predict placenta accreta.


Oncology | 2018

Zone Formation of Lymphocyte Infiltration at Invasive Front as a Biomarker of Prognosis in Endometrial Carcinomas

Morikazu Miyamoto; Masashi Takano; Hitoshi Tsuda; Hiroko Matuura; Tadashi Aoyama; Hiroaki Soyama; Kento Kato; Hideki Iwahashi; Hiroki Ishibashi; Tomoyuki Yoshikawa; Ayako Suzuki; Junko Hirata; Kenichi Furuya

Objective: The clinical significance of lymphocyte infiltration (LI) at the invasive front in endometrial carcinomas (EC) has not been determined. The aim of the current study was to evaluate the association between zone formation of LI at the invasive front of the tumor margin and prognoses of the patients with EC. Methods: All available pathological slides of the enrolled cases were reviewed, and the degree of LI at the invasive front was categorized into 2 groups: strong LI and weak LI. Clinical significance of LI was evaluated retrospectively. Results: A total of 333 cases with EC were enrolled in the study: 225 cases with weak LI and 108 cases with strong LI. Weak LI was more frequently observed in the patients with grade1/2 endometrioid EC. Multivariate analyses for progression-free survival (PFS) and overall survival (OS) revealed that weak LI was identified as an independent worse prognostic factor for OS (p = 0.004) in addition to PFS (p = 0.022). Conclusion: Weak LI at the invasive front of the tumor margin was associated with worse prognoses in EC. Although further studies are needed, it is suggested that LI could be a biomarker of prognoses in EC.


Taiwanese Journal of Obstetrics & Gynecology | 2017

Response to Correspondence “Asymptomatic uterine rupture detected at cesarean section: Some different viewpoints”

Hiroaki Soyama; Morikazu Miyamoto; Hidenori Sasa; Hiroki Ishibashi; Masashi Takano; Kenichi Furuya

We appreciate the opportunity to address the comments and concerns raised by Dr. Matsubara about our previous report [1]. We agree with his comments and would like to reply to his questions. To answer his first question, she did not complain of uterine contractions and was not at risk of preterm birth. Thus, Matsubaras hypothesis that the presence/absence of uterine contractions may affect rupture extension might be reasonable. In addition, the smooth muscle tissue around the rupture had become hardened granulation tissue. This might be one of the reasons preventing the progression of the rupture. The second question was whether the rupture was covered by the intestine/mesentery/omentum. The rupture was actually covered only partially by the right fallopian tube, mesosalpinx, and partial omentum. Matsubaras concept of “masked uterine rupture” is that the rupture is tightly covered by other abdominal tissues [2]; therefore, our case did not completely match his concept. However, our cases partial adhesion might have prevented the enlargement of the rupture to some extent. To answer his final question, we always tend to check the fundus and the back of the uterus by extracting the uterus from the abdominal cavity. However, as Dr. Matsubara mentioned, it is sometimes difficult to check the fundus due to severe adhesion around the uterus. If these conditions were exhibited in the present case, we could not have detected the rupture, and perhaps, the cesarean section would have been finished without repairing the rupture. If the repair is not performed, some patients with the condition may remain asymptomatic and the rupture may spontaneously close. However, other patients suffer from several complications. Generally, because of the reflux of menstrual blood from the rupture hole into the abdominal cavity, symptoms including dysmenorrhea, chronic pelvic pain, postmenstrual spotting, and prolonged menstrual bleeding may develop. Furthermore, this blood accumulation may cause deterioration of uterine mucus quality, block the passage of spermatozoa, or


Oncology | 2017

Small Foci of Serous Component as a Predictor of Recurrence and Prognosis for Stage IA Endometrial Carcinomas

Morikazu Miyamoto; Masashi Takano; Hitoshi Tsuda; Hiroaki Soyama; Tadashi Aoyama; Hiroki Ishibashi; Kento Kato; Hideki Iwahashi; Hiroko Matuura; Tomoyuki Yoshikawa; Ayako Suzuki; Junko Hirata; Kenichi Furuya

Objective: Most of the endometrial carcinomas are detected in early stages and have a better prognosis; however, predictive factors for recurrence have not been determined. Methods: Patients with grade 1 endometrioid carcinoma (EG1) according to the 2014 WHO criteria at FIGO 2009 stage IA that were identified through scanning medical charts were included, and we assessed whether the presence of uterine serous carcinoma (SC) component which comprised less than 5% of the total volume using the ovarian two-tiered grading system could be a recurrent risk factor in these patients. Results: Among 126 cases which met inclusion criteria, 12 cases had SC. SC tumors were divided into 2 groups: SC resembling high-grade serous carcinoma (HGSC) and SC resembling low-grade serous carcinoma (LGSC). Five (3.9%) cases had HGSC and 7 (5.6%) cases had LGSC. Recurrence was observed in 3 of all cases (2.3%): 2 cases with HGSC, and 1 case with LGSC. Regarding several clinicopathological factors, only the presence of SC was associated with recurrence. The sensitivity and specificity to predict recurrence using this system were 100 and 93%, respectively. Conclusion: The identification of SC using the ovarian two-tiered grading system could be an accurate predictor of recurrence in stage IA EG1.


Molecular and Clinical Oncology | 2017

Role of endometriosis as a prognostic factor for post‑progression survival in ovarian clear cell carcinoma

Hiroki Ishibashi; Masashi Takano; Morikazu Miyamoto; Hiroaki Soyama; Hiroko Matsuura; Tadashi Aoyama; Tomoyuki Yoshikawa; Kento Kato; Hitoshi Tsuda; Kenichi Furuya

The clinical significance of coexistence of endometriosis (EM) in ovarian clear cell carcinoma (CCC) has not yet been determined. The aim of the present study was to analyze the correlation of endometriosis with clinicopathological factors in CCC. The cases with CCC that received primary debulking surgery at the present hospital between 1990 and 2013 were identified. Retrospective analysis was conducted to evaluate the association between complications with EM and clinicopathological features in CCC. Of the 105 cases enrolled in the study, 45 cases were complicated with EM, and 60 cases did not have EM (non-EM). The patients with EM were diagnosed at a younger age (P=0.03), and at earlier stages (P<0.01) compared with non-EM cases. Although there was no significant difference of progression-free survival (P=0.36), complications with EM were identified as an independent prognostic factor for overall survival (OS; P<0.01) by multivariate analysis. A total of 48 patients (45.7%) developed recurrence: 18 patients in EM-group and 30 patients in non-EM group. There were no significant differences of clinicopathological factors in the treatment at recurrence between both groups. Recurrent cases in EM had significantly worse post-progression survival (PPS) compared with recurrent non-EM group (P<0.01). Multivariate analysis for PPS demonstrated that complications with EM (P<0.01) were identified as a worse prognostic factor. In CCC, the complication with EM was identified as a significant worse prognostic factor for PPS in recurrent cases. Additionally, EM was significantly associated with OS in all cases with CCC. Novel treatment strategies are therefore necessary for recurrent CCC, particularly for cases exhibiting EM.


PLOS ONE | 2016

Relation between Birth Weight and Intraoperative Hemorrhage during Cesarean Section in Pregnancy with Placenta Previa

Hiroaki Soyama; Morikazu Miyamoto; Hiroki Ishibashi; Masashi Takano; Hidenori Sasa; Kenichi Furuya

Background Placenta previa, one of the most severe obstetric complications, carries an increased risk of intraoperative massive hemorrhage. Several risk factors for intraoperative hemorrhage have been identified to date. However, the correlation between birth weight and intraoperative hemorrhage has not been investigated. Here we estimate the correlation between birth weight and the occurrence of intraoperative massive hemorrhage in placenta previa. Materials and Methods We included all 256 singleton pregnancies delivered via cesarean section at our hospital because of placenta previa between 2003 and 2015. We calculated not only measured birth weights but also standard deviation values according to the Japanese standard growth curve to adjust for differences in gestational age. We assessed the correlation between birth weight and the occurrence of intraoperative massive hemorrhage (>1500 mL blood loss). Receiver operating characteristic curves were constructed to determine the cutoff value of intraoperative massive hemorrhage. Results Of 256 pregnant women with placenta previa, 96 (38%) developed intraoperative massive hemorrhage. Receiver-operating characteristic curves revealed that the area under the curve of the combination variables between the standard deviation of birth weight and intraoperative massive hemorrhage was 0.71. The cutoff value with a sensitivity of 81.3% and specificity of 55.6% was −0.33 standard deviation. The multivariate analysis revealed that a standard deviation of >−0.33 (odds ratio, 5.88; 95% confidence interval, 3.04–12.00), need for hemostatic procedures (odds ratio, 3.31; 95% confidence interval, 1.79–6.25), and placental adhesion (odds ratio, 12.68; 95% confidence interval, 2.85–92.13) were independent risk of intraoperative massive hemorrhage. Conclusion In patients with placenta previa, a birth weight >−0.33 standard deviation was a significant risk indicator of massive hemorrhage during cesarean section. Based on this result, further studies are required to investigate whether fetal weight estimated by ultrasonography can predict hemorrhage during cesarean section in patients with placental previa.


Taiwanese Journal of Obstetrics & Gynecology | 2018

Marginal sinus placenta previa is a different entity in placenta previa: A retrospective study using magnetic resonance imaging

Hiroki Ishibashi; Morikazu Miyamoto; Hiroaki Soyama; Hiroshi Shinmoto; Wakana Murakami; Masaya Nakatsuka; Takahiro Natsuyama; Masashi Takano; Masashi Yoshida; Kenichi Furuya


Cancer Chemotherapy and Pharmacology | 2018

Addition of bevacizumab to gemcitabine for platinum-resistant recurrent ovarian cancer: a retrospective analysis.

Kazuki Takasaki; Morikazu Miyamoto; Masashi Takano; Hiroaki Soyama; Tadashi Aoyama; Hiroko Matsuura; Kento Kato; Takahiro Sakamoto; Mika Kuwahara; Hideki Iwahashi; Hiroki Ishibashi; Tomoyuki Yoshikawa; Kenichi Furuya

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Hiroaki Soyama

National Defense Medical College

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Kenichi Furuya

National Defense Medical College

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Morikazu Miyamoto

National Defense Medical College

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Masashi Takano

National Defense Medical College

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Kento Kato

National Defense Medical College

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Hideki Iwahashi

National Defense Medical College

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Tadashi Aoyama

National Defense Medical College

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Tomoyuki Yoshikawa

National Defense Medical College

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Hidenori Sasa

National Defense Medical College

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Hitoshi Tsuda

National Defense Medical College

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