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Dive into the research topics where Masaki Kuwahara is active.

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Featured researches published by Masaki Kuwahara.


Surgery Today | 1998

POOR PROGNOSIS IN ESOPHAGEAL CANCER PATIENTS WITH POSTOPERATIVE COMPLICATIONS

Toshihiro Hirai; Yoshinori Yamashita; Hidenori Mukaida; Masaki Kuwahara; Hideki Inoue; Tetsuya Toge

We investigated the relationship between postoperative complications and prognosis in esophageal cancer patients. Two hundred five patients with esophageal cancer were divided into three case groups. Group A (n = 100) consisted of cases without postoperative complications. Groups B (n = 58) and C (n = 47) consisted of cases with minor and major postoperative complications. The 5-year survival rates were 41.8%, 21.3%, and 20.2% in groups A, B, and C, respectively. There was a significant difference in the prognosis between groups A and B, and also between groups A and C. Any patients who died within 5 years without a relapse their cases were excluded from the study; the 5-year survival rates were 46.7%, 32.3%, and 22.5% in groups A, B, and C, respectively, with a significant difference between groups A and B. There were no significant differences between the three groups regarding the patient characteristics. These results therefore indicate that postoperative complications might contribute to a poor prognosis in cancer patients.


Surgery Today | 1997

Enhancing effect of thoraco-laparotomy on liver metastasis and the role played by active oxygens in its mechanism

Toshihiro Hirai; Akihiro Yoshimoto; Takashi Iwata; Yoshinori Yamashita; Masaki Kuwahara; Tetsuya Toge

The enhancing effect on liver metastasis produced by the excessive surgical stress of thoraco-laparotomy (TL), and its regulation with a radical scavenger, were studied in 10-week-old Donryu rats. The rats were divided into three groups: those given thoraco-laparotomy for 1h (the TL group); those given laparotomy alone for 1 h (the L group); those given a short laparotomy (the C group). The effects of treatment with 5 mg/kg of EPC-K1 was assessed in the TL group. A rat hepatocellular carcinoma cell line AH 60C (5× 105 cells) was administered into the portal vein under general anesthesia. The number of metastatic liver nodules was counted 3 weeks later, and the lipid peroxide (LPO) levels of the liver and serum were measured by the TBA method on postoperative days (PODs) 1,2, and 3. The number of metastatic liver nodules was 40.6±29.7, 15.0±15.8, and 13.7±9.4 in the TL, L, and C groups, respectively. When EPC-K1 was administered to the TL group, the LPO level on POD 1 decreased from 49.8±25.8 to 18.9±7.9nM/g, and the number of metastatic liver nodules decreased from 27.2±30.0 to 8.9±12.7 in parallel. The findings of this study suggested that the excessive surgical stress produced by thoraco-laparotomy enhanced liver metastasis in parallel with an increase in LPO levels; however, the radical scavenger EPC-K1 could aid in reversing this effect.


Surgery Today | 1999

Finger bougie method compared with pyloroplasty in the gastric replacement of the esophagus

Yoshinori Yamashita; Toshihiro Hirai; Hidenori Mukaida; Akihiro Yoshimoto; Masaki Kuwahara; Hideki Inoue; Tetsuya Toge

To elucidate the necessity of pyloroplasty for the gastric tube through the posterior mediastinum in esophageal surgery, gastric emptying and duodenogastric reflux (DGR) were evaluated in 16 cases undergoing an anterior pylorectomy (group P) and in 16 cases treated by the finger bougie method (group F). First, the obstruction and reflux symptoms were examined based on a patient questionnaire using a brief scoring system. The median value of the symptom score showed the patients in P to have more symptoms than those in F; however, the difference was not significant (8.0 vs 6.0). Secondly, the swallowed Tc O4− (85 MBq) was counted using a gamma camera at three sites on the sternal bone in the upright position based on a gastric transit scintigram. Both the descending time of the RI peak and the clearance rates were similar between the two groups. Thirdly, intragastric 24-h pH monitoring was carried out. Antimony pH sensors were anchored 5 and 15 cm below the esophagogastrostomy. We could not find any difference between the two groups in both the % time pH>4 and %time pH>7. These findings thus revealed no big difference between groups P and F. The finger bougie method to drain the vagotomized posterior mediastinal stomach was found to achieve results similar to conventional pyloroplasty, while it was also simpler and safer.


The Japanese Journal of Thoracic and Cardiovascular Surgery | 1998

Clinical evaluation of adjuvant chemoradiotherapy with CDDP, 5-Fu, and VP-16 for advanced esophageal cancer

Hidenori Mukaida; Toshihiro Hirai; Yoshinori Yamashita; Kazuhiro Yoshida; Jun Hihara; Masaki Kuwahara; Hideki Inoue; Tetsuya Toge

OBJECTIVES The aim of this study was to evaluate the efficacy of adjuvant chemoradiotherapy following surgery in patients with advanced esophageal cancer. SUBJECTS AND METHODS We followed the cases of 57 such patients treated at our hospital, involving 19 who received adjuvant chemoradiotherapy (CR group), 19 who received radiotherapy alone (R group), and 19 who did received neither (N group). In the CR group, chemotherapy, consisting of cis-diaminodichloroplatinum (CDDP), 5-fluorouracil (5-FU), and etoposide (VP-16), was combined with radiotherapy was administered from 4 weeks after surgery. Concurrent radiotherapy was started at 3 weeks after esophagectomy. CDDP at 50 mg/m2 was administered on days 1 and 7.5-FU at 500 mg/m2 and VP-16 at 60 mg/m2 were administered on days 3, 4, and 5. Thirteen patients (68.4%) were treated with more than 2 cycles of chemotherapy combined with radiation. RESULTS Side-effects of severe anorexia (grade 3) and leukocytopenia (< 1900/microliter) were observed in 47% and 39% of the patients, respectively. However no treatment-related death was observed. The 5-year-survival rate was 25.2%, 18.9%, and 15.8%, in the CR group, R group, and N group, respectively. The recurrence rate was 66.7% in the CR group, which was higher than in the matched control groups (46.2% in the N group and 54.5% in the R group), but with no a significant difference. CONCLUSION These results suggested that adjuvant chemoradiotherapy did not contribute to improvement in prognosis for these patients with advanced esophageal cancer.


Diseases of The Esophagus | 1998

Clinical results of transhiatal esophagectomy for carcinoma of the lower thoracic esophagus according to biological markers.

Toshihiro Hirai; Masaki Kuwahara; Kazuhiro Yoshida; Yoshihiro Kagawa; Jun Hihara; Yoshinori Yamashita; Tetsuya Toge


Diseases of The Esophagus | 1999

p53, p21(Waf1/Cip1) and cyclin D1 protein expression and prognosis in esophageal cancer

Masaki Kuwahara; Toshihiro Hirai; Kazuhiro Yoshida; Yoshinori Yamashita; Jun Hihara; Hideki Inoue; Tetsuya Toge


Jpn J Gastroenterol Surg, Nihon Shokaki Geka Gakkai zasshi | 2007

A Case of Metastatic Gastric Cancer from Rectal Cancer

Ryutaro Sakabe; Naoki Hirabayashi; Yukio Sato; Wataru Takiyama; Minoru Kameoka; Akira Nakashima; Masaki Kuwahara; Shuji Saeki; Hidenori Mukaida; Yoshinori Yamashita


Diseases of The Esophagus | 1999

Poor prognosis in esophageal cancer patients with post-operative complications: surgical oncotaxis

Jun Hihara; Toshihiro Hirai; Yoshinori Yamashita; Kazuhiro Yoshida; Masaki Kuwahara; Yoshihiro Kagawa; Tetsuya Toge


Nihon Rinsho Geka Gakkai Zasshi (journal of Japan Surgical Association) | 1997

PATHOLOGICAL STUDY ON THE MUCOSAL DAMAGE OF GASTRIC REPLACEMENT OF THE ESOPHAGUS AFTER THE POSTOPERATIVE RADIATION

Takashi Iwata; Hiroki Kuniyasu; Toshihiro Hirai; Yoshinori Yamashita; Akihiro Yoshimoto; Masaki Kuwahara; Tetsuya Toge


Nihon Rinsho Geka Gakkai Zasshi (journal of Japan Surgical Association) | 2005

CLINICAL PATHWAY FOR LOBECTOMY COMBINED WITH MEDIASTINAL LYMPHADENECTOMY IN PATIENTS WITH PRIMARY LUNG CANCER

Yoshinori Yamashita; Hidenori Mukaida; Masaki Kuwahara; Ryutaro Sakabe; Minoru Kameoka; Yukio Sato; Kazuhito Hisamatsu; Naoki Hirabayashi; Wataru Takiyama

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Naoki Hirabayashi

Wakayama Medical University

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