Masafumi Oyama
Saitama Medical University
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Featured researches published by Masafumi Oyama.
European Urology | 2014
Nobuyuki Tanaka; Eiji Kikuchi; Suguru Shirotake; Kent Kanao; Kazuhiro Matsumoto; Hiroaki Kobayashi; Yasumasa Miyazaki; Hiroki Ide; Jun Obata; Katsura Hoshino; Nozomi Hayakawa; Yujiro Ito; Takeo Kosaka; Kiichiro Kodaira; Masafumi Oyama; Akira Miyajima; Tetsuo Momma; Ken Nakagawa; Munehisa Ueno; Mototsugu Oya
BACKGROUND Few studies have discussed the prognostic impact of serum C-reactive protein (CRP) level in upper tract urothelial carcinoma (UTUC). OBJECTIVE To investigate whether the perioperative level of CRP provides additional prognostic information following radical nephroureterectomy (RNU). DESIGN, SETTING, AND PARTICIPANTS A total of 564 patients with UTUC from a retrospective multi-institutional cohort were included. The median follow-up was 32 mo. INTERVENTION All patients underwent RNU without neoadjuvant chemotherapy, while 106 patients (18.8%) received adjuvant chemotherapy. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS Associations between perioperative CRP level and outcome were assessed using multivariate analysis. A serum CRP level >0.50mg/dl was defined as elevated. RESULTS AND LIMITATIONS Preoperative CRP (pre-CRP) level was elevated in 136 patients (24.1%). Multivariate analysis showed that pre-CRP elevation was an independent predictor of subsequent disease recurrence (hazard ratio [HR]: 1.47 for CRP 0.51-2.00; HR: 1.89 for CRP >2.00). Five-year recurrence-free survival rates were 69.2% in patients with pre-CRP levels ≤ 0.50 mg/dl, 54.3% in patients with pre-CRP levels between 0.51 and 2.00 mg/dl, and 35.4% in patients with pre-CRP levels >2.00 mg/dl (p<0.001). Similar results were found in cancer-specific mortality, showing that pre-CRP elevation was an independent predictor of worse outcome (HR: 1.74 for CRP 0.51-2.00; HR: 2.31 for CRP >2.00). In a subgroup analysis of the elevated pre-CRP group, postoperative normalisation of CRP level was an independent predictor of better outcome. This study is limited by its retrospective nature as well as its heterogeneous group of patients and variable follow-up protocols resulting from the multi-institution design. CONCLUSIONS Serum CRP may become a possible biomarker in UTUC, suggesting that patients with an elevated pre-CRP level could be predicted to have subsequent disease recurrence and cancer-specific mortality, while postoperative normalisation of CRP level was an independent predictor for prognosis.
Human Gene Therapy | 2000
Masafumi Oyama; Takashi Ohigashi; Michio Hoshi; Jun Nakashima; Masaaki Tachibana; Masaru Murai; Keiichi Uyemura; Takahito Yazaki
G207, a conditionally replicating herpes vector, efficiently kills human bladder cancer cells in vitro. To evaluate the therapeutic potential of G207, we have established three in vivo models similar to the clinical situation. In vivo, G207 was intraneoplastically, intravesically, or intravenously inoculated in nude mice. Intraneoplastic inoculation into subcutaneous tumor caused significant tumor growth inhibition. Intravesical inoculation of G207 also caused decreased tumor growth in an orthotopic human bladder cancer model. Furthermore, multiple intravenous inoculation markedly inhibited subcutaneous tumor growth. These results suggest that intravesical therapy with G207 is effective for localized bladder tumor, especially for carcinoma in situ (CIS), and intravenous therapy with G207 is promising for invasive or metastasized bladder tumor.
Japanese Journal of Cancer Research | 2000
Masafumi Oyama; Takashi Ohigashi; Michio Hoshi; Masaru Murai; Keiichi Uyemura; Takahito Yazaki
Over the last few years, a conditionally replicating herpes simplex virus 1 (HSV‐1) vector, G207 has been used for the treatment of several malignant tumors. In this article we evaluate the antitumoral effect of G207 against prostate cancer in vitro and in vivo. The susceptibility of the human prostate cancer cell lines, DU145 and PC3 to G207 at a multiplicity of infection (MOI) of 0.1 was examined. In addition, the growth characteristics of G207 were assessed. Athymic mice with s.c. tumors were inoculated in vivo intraneoplastically with 1x107 plaque‐forming units (PFU) of G207. For the pathological analyses, s.c. tumors were stained with X‐gal. DU145 and PC3 were efficiently destroyed by G207 within 7 days. The viral yields of G207 increased time‐dependently. In vivo, the intraneoplastic inoculation of G207 induced a significant inhibition of the tumor growth. The mean tumor growth ratio was significantly inhibited in the G207‐treated tumors (DU145, P< 0.0001; PC3, P < 0.001 versus controls). In a pathological study, many lacZ‐positive cells were diffusely present in the G207‐treated tumors. G207 showed a significant antitumoral effect against human prostate cancer cell lines, and thus may be considered a useful agent for the treatment of prostate cancer.
The Journal of Urology | 2015
Suguru Shirotake; Eiji Kikuchi; Nobuyuki Tanaka; Kazuhiro Matsumoto; Yasumasa Miyazaki; Hiroaki Kobayashi; Hiroki Ide; Jun Obata; Katsura Hoshino; Gou Kaneko; Masayuki Hagiwara; Takeo Kosaka; Kent Kanao; Kiichiro Kodaira; Satoshi Hara; Masafumi Oyama; Tetsuo Momma; Akira Miyajima; Ken Nakagawa; Shintaro Hasegawa; Yosuke Nakajima; Mototsugu Oya
PURPOSE Current guidelines do not yet provide any recommendations for adjuvant chemotherapy in patients with upper tract urothelial carcinoma managed with radical nephroureterectomy. We evaluated whether an adjuvant chemotherapeutic regimen would affect the clinical outcome in patients with high risk upper tract urothelial carcinoma. MATERIALS AND METHODS We identified 873 patients who had undergone radical nephrouretectomy for localized upper tract urothelial carcinoma at 14 Japanese institutions between 1993 and 2011. We assessed whether the type of regimen, such as methotrexate, vinblastine, doxorubicin and cisplatin, and gemcitabine and cisplatin, in an adjuvant setting, could affect the subsequent clinical outcome of patients with upper tract urothelial carcinoma. RESULTS On multivariate analysis pathological T stage, tumor grade, lymphovascular invasion and lymph node involvement were prognostic factors for recurrence-free survival and cancer specific survival. We defined 229 patients with 3 or more of these factors as the high risk group. In an analysis according to adjuvant regimen, Kaplan-Meier curves showed that the 1 and 2-year recurrence-free survival rates in the methotrexate, vinblastine, doxorubicin and cisplatin treated group were 71.4% and 47.9%, which were significantly higher than in the gemcitabine and cisplatin treated group (48.2% and not reached, p=0.022) or those not treated with adjuvant chemotherapy (53.4% and 39.6%, p=0.039). Similar results were observed in terms of cancer specific survival. CONCLUSIONS Our study showed that pT3-4, tumor grade 3, positive lymphovascular invasion and lymph node involvement were independent risk factors for disease mortality in patients with upper tract urothelial carcinoma treated with radical nephroureterectomy. In the high risk group methotrexate, vinblastine, doxorubicin and cisplatin adjuvant chemotherapy contributed to improve subsequent mortality compared to gemcitabine and cisplatin or no adjuvant chemotherapy.
Urologic Oncology-seminars and Original Investigations | 2014
Nobuyuki Tanaka; Eiji Kikuchi; Kent Kanao; Kazuhiro Matsumoto; Suguru Shirotake; Hiroaki Kobayashi; Yasumasa Miyazaki; Hiroki Ide; Jun Obata; Katsura Hoshino; Nozomi Hayakawa; Takeo Kosaka; Masafumi Oyama; Akira Miyajima; Tetsuo Momma; Ken Nakagawa; Masahiro Jinzaki; Yosuke Nakajima; Mototsugu Oya
BACKGROUND AND OBJECTIVE Few studies have addressed the predictive value of positive urine cytology for prognosis in patients with upper tract urothelial carcinoma (UTUC). We investigated whether the status of preoperative urine cytology could provide additional prognostic information following radical nephroureterectomy (RNU). MATERIALS AND METHODS The study included 474 patients with primary nonmetastatic UTUC (pTa-4N0M0) from a retrospective multi-institutional cohort. The median follow-up period was 35 months. Associations between the status of urine cytologic evaluation and outcomes were analyzed using multivariate Cox regression models. Urine cytology was evaluated preoperatively using voided samples. Disease recurrence was defined as any relapse in nonbladder lesions and was coded separately from intravesical recurrence. RESULTS Positive urine cytology was detected in 184 patients (38.8%) preoperatively. Disease recurrence occurred in 127 patients, while intravesical recurrence occurred in 219 patients; 83 patients died of UTUC during follow-up. Kaplan-Meier analysis revealed that only the incidence of intravesical recurrence was significantly associated with the status of urine cytologic evaluation (P = 0.024); the intravesical recurrence-free survival rates at 1 and 3 years following RNU were 61.4% and 46.2% in patients with positive urine cytology and 71.1% and 51.6% in their counterparts, respectively. Multivariate analysis showed that gender (hazard ratio [HR] = 1.74, 95% confidence interval [CI]; 1.28-2.43), tumor multifocality in RNU specimens (HR = 1.64, 95% CI; 1.09-2.47), and positive urine cytology (HR = 1.41, 95% CI; 1.08-1.85) were independent risk factors for subsequent intravesical recurrence. CONCLUSIONS The results showed the prognostic value of positive urine cytology in patients with primary UTUC, and preoperative positive urine cytology may be associated with a significant increase in the prevalence of intravesical recurrence following RNU.
The Journal of Urology | 2001
Masafumi Oyama; Takashi Ohigashi; Michio Hoshi; Masaru Murai; Keiichi Uyemura; Takahito Yazaki
PURPOSE Surgical removal remains the only potentially curative therapy for renal cell carcinoma. In this study we evaluated the inhibitory effect of the replication competent engineered herpes simplex virus type 1, G207, for renal cell carcinoma in vitro and in vivo. MATERIALS AND METHODS The nature of G207 enables it to replicate within cancer cells, thus, causing cytolysis, but replication is restricted within normal cells. The susceptibility of the human renal cancer cell lines ACHN and A498 to G207 at a multiplicity of infection of 0.1 was examined. In addition, the growth characteristics of G207 was assessed. In vivo athymic mice bearing subcutaneous tumors were inoculated with 1 x 10(7) plaque forming units of G207 intra-neoplastically. For pathological analysis subcutaneous tumors were stained with X-gal. RESULTS Two cell lines were efficiently destroyed by G207 within 1 week. The viral yields of G207 increased in a time dependent manner. In vivo the intra-neoplastic inoculation of G207 caused significantly decreased tumor growth in athymic mice harboring subcutaneous human renal cancer cells. On day 14 the mean growth ratio of ACHN and A498 lesions was significantly inhibited in G207 treated compared to control tumors (p <0.005 and <0.0001, respectively). CONCLUSIONS These results suggest that G207 should be considered another potential therapeutic agent for renal cell carcinoma.
PLOS ONE | 2014
Takashi Okabe; Megumi Kumagai; Yoshihiro Nakajima; Suguru Shirotake; Kiichiro Kodaira; Masafumi Oyama; Munehisa Ueno; Masaaki Ikeda
In mammals, the circadian rhythm central generator consists of interactions among clock genes, including Per1/2/3, Cry1/2, Bmal1, and Clock. Circadian rhythm disruption may lead to increased risk of cancer in humans, and deregulation of clock genes has been implicated in many types of cancers. Among these genes, Per2 is reported to have tumor suppressor properties, but little is known about the correlation between Per2 and HIF, which is the main target of renal cell carcinoma (RCC) therapy. In this study, the rhythmic expression of the Per2 gene was not detectable in renal cancer cell lines, with the exception of Caki-2 cells. In Caki-2 cells, HIF1α increased the amplitude of Per2 oscillation by directly binding to the HIF-binding site located on the Per2 promoter. These results indicate that HIF1α may enhance the amplitude of the Per2 circadian rhythm.
Human Cell | 2008
Yutaka Horiguchi; Eiji Kikuchi; Choichiro Ozu; Toru Nishiyama; Masafumi Oyama; Minoru Horinaga; Kunihiko Yoshioka; Masaaki Tachibana
Various animal models of bladder tumor have been developed for the preclinical evaluation of therapeutic modalities for the treatment of bladder cancers. The ideal model for the investigation of therapeutic effects of proposed novel intravesical treatments requires the mass of the implanted tumor to be confined to the urothelium of the bladder at least for the initial phase. However, previously reported bladder tumor models are not suitable for the evaluation of intravesical therapies for the treatment of superficial bladder cancer, since the muscle invasive tumors have developed from the beginnings of the experiments. These models are too aggressive to study local treatment effects. In the current study, we demonstrated that careful instillation of MBT-2 mouse bladder cancer cells into the bladder of a syngenic C3H/HeJ mouse could establish a superficial bladder tumor with an incidence of 100%. The procedure and technique for handling animals are simple for standard animal investigators. Maintenance of the in vitro conditions of MBT-2 cells without contamination of Mycoplasma and careful selection of the substrain of C3H mouse seem to be essential for stable tumor establishment. This bladder tumor model appeared to be easy to reproduce among several investigators in different institutions. The orthotopic bladder tumor model, which was confined to urothelium, lets us evaluate various intravesical treatment strategies.
Photodiagnosis and Photodynamic Therapy | 2015
Keiji Inoue; Satoshi Anai; Kiyohide Fujimoto; Yoshihiko Hirao; Hiroshi Furuse; Fumitake Kai; Seiichiro Ozono; Takahiko Hara; Hideyasu Matsuyama; Masafumi Oyama; Munehisa Ueno; Hideo Fukuhara; Mamoru Narukawa; Taro Shuin
BACKGROUND Photodynamic diagnosis (PDD) of non-muscle-invasive bladder cancer (NMIBC) following transurethral administration of a hexalated form of 5-aminolevulinic acid (5-ALA), 5-ALA hexyl ester, is widely performed in Western countries. In this study, effectiveness and safety of the oral administration of 5-ALA is assessed in a phase II/III study of PDD for NMIBC in comparison to those of conventional white-light endoscopic diagnosis. METHODS Patients with NMIBC were allocated to two groups that were orally administered 10 and 20 mg/kg of 5-ALA under the double-blind condition. Effectiveness was evaluated by setting the primary endpoint to sensitivity. Safety was also analyzed. Moreover, clinically recommended doses of 5-ALA was also investigated as an investigator-initiated multicenter cooperative clinical trial in which five medical institutions participated. RESULTS All 62 enrolled patients completed the clinical trial. The sensitivities of PDD were higher (84.4 and 75.8% in the 10 and 20 m g/kg-groups, respectively) than those of conventional endoscopic diagnosis (67.5 and 47.6%, respectively) (p = 0.014 and p < 0.001, respectively). Five episodes of serious adverse events developed in four patients; whereas a causal relationship with the investigational agent was ruled out in all episodes. CONCLUSION This investigator-initiated clinical trial confirmed the effectiveness and safety of PDD for NMIBC following oral administration of 5-ALA. Both doses of 5-ALA may be clinically applicable; however, the rate of detecting tumors only by PDD was higher in the 20 mg/kg-group suggesting that this dose would be more useful.
Photodiagnosis and Photodynamic Therapy | 2016
Keiji Inoue; Hideyasu Matsuyama; Kiyohide Fujimoto; Yoshihiko Hirao; Hironobu Watanabe; Seiichiro Ozono; Masafumi Oyama; Munehisa Ueno; Yoshiki Sugimura; Hiroaki Shiina; Hiromitsu Mimata; Haruhito Azuma; Yasushi Nagase; Akio Matsubara; Yoichi M. Ito; Taro Shuin
OBJECTIVE To examine the utility and safety of photodynamic diagnosis (PDD) after oral administration of 5-aminolevulinic acid (5-ALA) (ALA-PDD) of non-muscle-invasive bladder cancer (NMIBC) using fluorescent-light (FL)-cystoscopy. METHODS The study was a single-arm, open-label, multi-center prospective study on ALA-PDD of NMIBC, with safety as the primary endpoint and efficacy as the secondary endpoint. Diagnostic potential was evaluated through comparisons with the conventional diagnostic method using a white-light (WL)-source. Clinically recommended doses were also examined. Oral administration of 5-ALA (1.0g/50mL) was performed 180-240min before FL-cystoscopy, and positive or negative results were judged using a WL-source and based on presence or absence of red fluorescence on exposure to a blue FL-source. RESULTS Regarding safety, the adverse drug reactions were observed as grade 1 pruritus in 1 patient (0.6%). As for efficacy, specificity and positive predictability were lower than those of a WL-source, but sensitivity was higher with a FL-source than with a WL-source. The proportion of patients with tumors detected only by FL-cystoscopy was greater than the proportion of patients with tumors detected only by conventional WL-cystoscopy. Moreover, not only sensitivity, but also the proportion of patients with tumors detected only by FL-cystoscopy, was highest among patients who received 5-ALA at ≧20mg/kg/body. CONCLUSIONS ALA-PDD was shown to be safe and effective. Furthermore, diagnostic accuracy of PDD increased with increased dose of 5-ALA, and the recommended dose was determined as ≧20mg/kg/body in the present study.