Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Masatoshi Yokoyama is active.

Publication


Featured researches published by Masatoshi Yokoyama.


Gynecologic Oncology | 2015

Clinical tumor diameter and prognosis of patients with FIGO stage IB1 cervical cancer (JCOG0806-A)

Tomoyasu Kato; Atsuo Takashima; Takahiro Kasamatsu; Kenichi Nakamura; Junki Mizusawa; Toru Nakanishi; Nobuhiro Takeshima; Shoji Kamiura; Takashi Onda; Toshiyuki Sumi; Masashi Takano; Hidekatsu Nakai; Toshiaki Saito; Kiyoshi Fujiwara; Masatoshi Yokoyama; Hiroaki Itamochi; Kazuhiro Takehara; Harushige Yokota; Tomoya Mizunoe; Satoru Takeda; Kenzo Sonoda; Tanri Shiozawa; Takayo Kawabata; Shigeru Honma; Haruhiko Fukuda; Nobuo Yaegashi; Hiroyuki Yoshikawa; Ikuo Konishi; Toshiharu Kamura

OBJECTIVEnIn order to determine indications for less radical surgery such as modified radical hysterectomy, the risk of pathological parametrial involvement and prognosis of FIGO stage IB1 cervical cancer patients undergoing standard radical hysterectomy with pre-operatively assessed tumor diameter≤2 cm were investigated.nnnMETHODSnWe conducted a retrospective multi-institutional chart review of patients with FIGO stage IB1 cervical cancer who underwent primary surgical treatment between 1998 and 2002. The eligibility criteria for the analyses were (i) histologically-proven squamous cell carcinoma, adenocarcinoma or, adenosquamous cell carcinoma, (ii) radical hysterectomy performed, (iii) clinical tumor diameter data available by MR imaging or specimens by cone biopsy, and (iv) age between 20 and 70. Based on the clinical tumor diameter, patients were stratified into those with the following tumors: i) 2 cm or less (cT≤2 cm) and ii) greater than 2 cm (cT>2 cm). We expected 5-year OS of ≥95% and parametrial involvement<2-3% for patients with cT≤2 cm who underwent radical hysterectomy.nnnRESULTSnOf the 1269 patients enrolled, 604 were eligible for the planned analyses. Among these, 571 underwent radical hysterectomy (323 with cT≤2 cm and 248 with cT>2 cm). Parametrial involvement was present in 1.9% (6/323) with cT≤2 cm and 12.9% (32/248) with cT>2 cm. Five-year overall survivals were 95.8% (95% CI 92.9-97.6%) in cT≤2 cm and 91.9% (95% CI 87.6-94.8%) in cT>2 cm patients.nnnCONCLUSIONnPatients with cT≤2 cm had lower risk of parametrial involvement and more favorable 5-year overall survival. They could therefore be good candidates for receiving less radical surgery.


Journal of Obstetrics and Gynaecology Research | 2005

Clinicopathologic analysis of the prognostic factors in women with coexistence of endometrioid adenocarcinoma in the endometrium and ovary

Noriko Nishimura; Toru Hachisuga; Masatoshi Yokoyama; Tsuyoshi Iwasaka; Tatsuhiko Kawarabayashi

Aim: To compare the survival and prognostic factors of patients with dual primary ovarian and endometrial cancers (primary group), and endometrial cancers metastatic to the ovaries (metastatic group).


Acta Cytologica | 2004

Analysis of Nuclear Chromatin Distribution in Cervical Glandular Abnormalities

Sumiko Watanabe; Tsuyoshi Iwasaka; Masatoshi Yokoyama; Michiko Uchiyama; Tsunehisa Kaku; Toshitaka Matsuyama

OBJECTIVEnTo measure the intensity of hematoxylin staining for the analysis of chromatin distribution and to define a clear set of standards.nnnSTUDY DESIGNnCervical smears obtained from 12 patients with glandular lesions, 5 with squamous lesions and 3 without cervical lesions were used for NIH image analysis (public domain NIH image program developed at the U.S. National Institute of Health, available through the Internet by anonymous ftp from zippy.nimh.nih.gov or on floppy disk from the National Technical Information Service, Springfield, Virginia). In addition, the same cervical smears were restained with propidium iodide, and the DNA content in the nuclei was compared with that with hematoxylin staining.nnnRESULTSnChromatin distribution was categorized into 3 patterns. Pattern A was that for which the highest staining density was localized in the periphery of the nucleus, while in pattern C it was localized in the center of the nucleus. Pattern B was the intermediate type between patterns A and C. In patients with adenocarcinoma, pattern B was predominant; pattern C was also relatively frequent in this group. In atypical glandular cells observed in patients with squamous lesions, patterns A and B were predominant and pattern C rarely seen. Analysis of DNA content in the nucleus revealed that nuclei showing pattern B contained significantly higher quantities of DNA than those showing pattern A.nnnCONCLUSIONnNuclear chromatin distribution seems to correlate well with DNA content, and analysis of the chromatin distribution pattern is helpful for the diagnosis of cervical glandular neoplasia.


Cancer Science | 2015

Human leukocyte antigen class II DRB1*1302 allele protects against cervical cancer: At which step of multistage carcinogenesis?

Koji Matsumoto; Hiroo Maeda; Akinori Oki; Naoyoshi Takatsuka; Toshiharu Yasugi; Reiko Furuta; Ranko Hirata; Akira Mitsuhashi; Kei Kawana; Takuma Fujii; Takashi Iwata; Yasuo Hirai; Masatoshi Yokoyama; Nobuo Yaegashi; Yoh Watanabe; Yutaka Nagai; Hiroyuki Yoshikawa

We investigated the role of human leukocyte antigen (HLA) class II alleles in multistage cervical carcinogenesis. Cross‐sectional analysis for HLA association with cervical cancer included 1253 Japanese women: normal cytology (NL, n = 341), cervical intraepithelial neoplasia grade 1 (CIN1, n = 505), CIN grade 2 or 3 (CIN2/3, n = 96), or invasive cervical cancer (ICC, n = 311). The HLA class II allele frequencies were compared by Fishers exact test or the χ2‐test. The Bonferroni adjustment corrected for multiple comparisons. Among the study subjects, 454 women with low‐grade squamous intraepithelial lesion cytology were prospectively monitored by cytology and colposcopy every 3–4 months to analyze cumulative risk of CIN3 within the next 10 years in relation to HLA class II alleles. HLA class II DRB1*1302 allele frequency was similar between women with NL (11.7%) and CIN1 (11.9%), but significantly decreased to 5.2% for CIN2/3 and 5.8% for ICC (P = 0.0003). Correction for multiple testing did not change this finding. In women with low‐grade squamous intraepithelial lesion cytology, the cumulative risk of CIN3 diagnosed within 10 years was significantly reduced among DRB1*1302‐positive women (3.2% vs. 23.7%, P = 0.03). In conclusion, the two different types of analysis in this single study showed the protective effect of the DRB1*1302 allele against progression from CIN1 to CIN2/3.


World Journal of Surgical Oncology | 2013

Pyomyositis associated with chemotherapy for endometrial cancer: a case report

Yoshifumi Nakao; Masatoshi Yokoyama; Satoshi Nishiyama; Mariko Hashiguchi; Satomi Aihara; Makio Yasunaga; Mitsuyo Noguchi; Tsuyoshi Iwasaka

Pyomyositis is a rare complication of chemotherapy for non-hematological malignancies. A 58-year-old woman with endometrial carcinoma, in whom pyomyositis developed during adjuvant chemotherapy, was presented in this report. After initiating empiric antibiotic therapy for febrile neutrocytopenia, screening CT showed multiple abscesses in the lower limbs. Operative drainage of the abscess was effective.


Journal of Gynecologic Oncology | 2018

Efficacy of palonosetron plus dexamethasone in preventing chemotherapy-induced nausea and emesis in patients receiving carboplatin-based chemotherapy for gynecologic cancers: a phase II study by the West Japan Gynecologic Oncology Group (WJGOG 131)

Shin Nishio; Satomi Aihara; Mototsugu Shimokawa; Akira Fujishita; Shuichi Taniguchi; Toru Hachisuga; Shintaro Yanazume; Hiroaki Kobayashi; Fumihiro Murakami; Fumitaka Numa; Kohei Kotera; Naofumi Okura; Naoyuki Toki; Masatoshi Yokoyama; Kimio Ushijima

Objective Palonosetron is effective for the management of acute and delayed chemotherapy-induced nausea and vomiting (CINV). While emetogenic carboplatin-based chemotherapy is widely used to treat gynecologic cancers, few studies have evaluated the antiemetic effectiveness of palonosetron in this setting. Methods A multicenter, single-arm, open-label phase II trial was conducted to evaluate the safety and effectiveness of palonosetron in controlling CINV in patients with gynecologic cancer. Chemotherapy-naïve patients received intravenous palonosetron (0.75 mg/body) and dexamethasone before the infusion of carboplatin-based chemotherapy on day 1. Dexamethasone was administered (orally or intravenously) on days 2–3. The incidence and severity of CINV were evaluated using the patient-completed Multinational Association of Supportive Care in Cancer Antiemesis Tool and treatment diaries. The primary endpoint was the proportion of patients experiencing complete control (CC) of vomiting, with “no rescue antiemetic medication” and “no clinically significant nausea” or “only mild nausea” in the delayed phase (24–120 hours post-chemotherapy). Secondary endpoints were the proportion of patients with a complete response (CR: “no vomiting” and “no rescue antiemetic medication”) in the acute (0–24 hours), delayed (24–120 hours), and overall (0–120 hours) phases, and CC in the acute and overall phases. Results Efficacy was assessable in 77 of 80 patients recruited. In the acute and delayed phases, the CR rates the primary endpoint, were 71.4% and 59.7% and the CC rates, the secondary endpoint, were 97.4% and 96.1%, respectively. Conclusion While palonosetron effectively controls acute CINV, additional antiemetic management is warranted in the delayed phase after carboplatin-based chemotherapy in gynecologic cancer patients (Trial registry at UMIN Clinical Trials Registry, UMIN000012806).


Gynecologic Oncology | 2006

MR imaging in endometrial carcinoma as a diagnostic tool for the absence of myometrial invasion

Yoshifumi Nakao; Masatoshi Yokoyama; Koichi Hara; Yasuko Koyamatsu; Makio Yasunaga; Yasuhiro Araki; Yukiko Watanabe; Tsuyoshi Iwasaka


Cancer Letters | 2006

Inhibitory effect of the tea polyphenol, (−)-epigallocatechin gallate, on growth of cervical adenocarcinoma cell lines

Mitsuyo Noguchi; Masatoshi Yokoyama; Sumiko Watanabe; Michiko Uchiyama; Yoshifumi Nakao; Kouichi Hara; Tsuyoshi Iwasaka


Cancer Letters | 2007

Retinoic acid receptor β2 is epigenetically silenced either by DNA methylation or repressive histone modifications at the promoter in cervical cancer cells

Zhongming Zhang; Keiichiro Joh; Hitomi Yatsuki; Wei Zhao; Hidenobu Soejima; Ken Higashimoto; Mitsuyo Noguchi; Masatoshi Yokoyama; Tsuyoshi Iwasaka; Tsunehiro Mukai


Acta Cytologica | 2004

Nongynecologic Cytology Practice Guideline

Christina S. Kong; Imok Cha; Sumiko Watanabe; Tsuyoshi Iwasaka; Masatoshi Yokoyama; Michiko Uchiyama; Tsunehisa Kaku; Toshitaka Matsuyama; Raj K. Gupta; David Gaskell; Carl Dowle; Sarla Naran; Sharda Lallu; Robert Fauck; Asya S. Ali; Diana Yin; Davis X. Yao; Madeline Vazquez; Suely Nonogaki; Alda Wakamatsu; Adhemar Longatto Filho; Sônia Maria Miranda Pereira; Maria Lúcia Utagawa; Venâncio Avancini FerreiraAlves; Celso di Loreto; Marina Yoshiê Sakamoto Maeda; Temístocles Lima; Roteli-Martins C; Kari Syrjänen; Anna Mhoyan

Collaboration


Dive into the Masatoshi Yokoyama's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge