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Dive into the research topics where Takahide Nakazawa is active.

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Featured researches published by Takahide Nakazawa.


American Journal of Roentgenology | 2007

Radiofrequency ablation of hepatocellular carcinoma: correlation between local tumor progression after ablation and ablative margin.

Takahide Nakazawa; Shigehiro Kokubu; Akitaka Shibuya; Koji Ono; Masaaki Watanabe; Hisashi Hidaka; Takeshi Tsuchihashi; Katsunori Saigenji

OBJECTIVE To identify the determinants of tumor progression, we examined the ablation zones and patterns of local progression of small single primary hepatocellular carcinomas after radiofrequency ablation. MATERIALS AND METHODS Eighty-five patients with single primary hepatocellular carcinoma less than 3 cm in diameter underwent complete tumor ablation. Clinical and biochemical features, tumor characteristics, tumor location within 5 mm from intrahepatic vessels, needle biopsy before treatment, and presence of ablative margin of 5 mm or more were statistically analyzed as determinants of local tumor progression. The Kaplan-Meier method and a Cox model were used for the analyses. Patterns of local tumor progression were examined by image analysis. RESULTS During a median observation period of 30.3 months, 14 (16.5%) of the 85 patients had local tumor progression. The results of the log-rank test showed that the presence of vessels contiguous with the tumor (p = 0.0292) and the absence of an ablative margin of at least 5 mm (p = 0.019) significantly correlated with local tumor progression. Cox regression analysis showed that the absence of an ablative margin of at least 5 mm was an independent factor (p = 0.04). The most common pattern of local tumor progression was a single viable outgrowth from the side of the ablated area when the ablative margin was less than 5 mm. Multiple viable outgrowths were observed in one case despite the presence of an ablative margin greater than 5 mm. CONCLUSION An ablation zone with an ablative margin of 5 mm or greater was the most important factor for local control of hepatocellular carcinoma.


Journal of Gastroenterology | 2008

Intrahepatic distant recurrence after radiofrequency ablation for a single small hepatocellular carcinoma: risk factors and patterns.

Yusuke Okuwaki; Takahide Nakazawa; Akitaka Shibuya; Koji Ono; Hisashi Hidaka; Masaaki Watanabe; Shigehiro Kokubu; Katsunori Saigenji

Background. The pathogenesis of frequent intrahepatic recurrence of hepatocellular carcinoma (HCC) after surgical resection or local ablation therapy remains uncertain. Risks and patterns of intrahepatic distant recurrence (IDR) of a single, primary HCC lesion after radiofrequency (RF) ablation were examined. Methods. Ninety patients with a single primary HCC lesion of less than 3 cm who had complete RF ablation were enrolled in the study. Risk factors for IDR and the patterns of IDR after RF ablation were analyzed. Results. The median follow-up was 37.4 months. IDR was observed in 44 (48.9%) patients. The cumulative rate of IDR was 10.4%, 52.5%, and 77.0% at 1, 3, and 5 years, respectively. Univariate analysis revealed that a pretreatment serum α-fetoprotein (AFP) level of ≥50 ng/ml (P = 0.0324), a des-γ-carboxy prothrombin (DCP) level of ≥40 mAu/ml (P = 0.006), an ablative margin of <5 mm of the ablation zone (P = 0.0306), and a prothrombin time of <70% (P = 0.0188) were related to IDR. A multivariate stepwise Cox proportional hazards regression model revealed that pretreatment serum AFP and DCP level and the ablative margin were independent risk factors for IDR pretreatment. Serum DCP level ≥ 40 mAu/ml (P = 0.025), local tumor progression (P = 0.011), and ablative margin < 5 mm (P = 0.024) were related to multiple IDR. Conclusions. HCC patients with high serum AFP or DCP before RF ablation should be carefully followed up to monitor any IDR. A suffi cient ablative margin in RF ablation for HCC is required to prevent IDR.


Hepatology Research | 2008

Occult hepatitis B virus infection as a risk factor for hepatocellular carcinoma in patients with chronic hepatitis C in whom viral eradication fails.

Yukiko Miura; Akitaka Shibuya; Shigeru Adachi; Atsuko Takeuchi; Takeshi Tsuchihashi; Takahide Nakazawa; Katsunori Saigenji

Aim:  Recent studies have suggested that an occult hepatitis B virus (HBV) infection negative for HBsAg but positive for HBV‐DNA contributes to hepatocellular carcinoma (HCC) development in patients with chronic hepatitis C. Some follow‐up studies have suggested the clinical importance of occult HBV infections in HCC development even after interferon (IFN) therapy, but a recent study denies the significance of the impact of occult HBV infection. Focusing on HCC development in patients in whom hepatitis C virus (HCV) eradication by interferon (IFN) therapy had failed, we conducted this study in order to assess the impact of occult HBV infections on HCC development in these patients.


Journal of Virology | 2009

Genetic Analysis of Hepatitis C Virus with Defective Genome and Its Infectivity in Vitro

Kazuo Sugiyama; Kenji Suzuki; Takahide Nakazawa; Kenji Funami; Takayuki Hishiki; Kazuya Ogawa; Satoru Saito; Kumiko W. Shimotohno; Takeshi Suzuki; Yuko Shimizu; Reiri Tobita; Makoto Hijikata; Hiroshi Takaku; Kunitada Shimotohno

ABSTRACT Replication and infectivity of hepatitis C virus (HCV) with a defective genome is ambiguous. We molecularly cloned 38 HCV isolates with defective genomes from 18 patient sera. The structural regions were widely deleted, with the 5′ untranslated, core, and NS3-NS5B regions preserved. All of the deletions were in frame, indicating that they are translatable to the authentic terminus. Phylogenetic analyses showed self-replication of the defective genomes independent of full genomes. We generated a defective genome of chimeric HCV to mimic the defective isolate in the serum. By using this, we demonstrated for the first time that the defective genome, as it is circulating in the blood, can be encapsidated as an infectious particle by trans complementation of the structural proteins.


European Journal of Internal Medicine | 2010

Entecavir is an optional agent to prevent hepatitis B virus (HBV) reactivation: A review of 16 patients

Masaaki Watanabe; Akitaka Shibuya; Juichi Takada; Yoshiaki Tanaka; Yusuke Okuwaki; Tsutomu Minamino; Hisashi Hidaka; Takahide Nakazawa; Wasaburo Koizumi

BACKGROUND Hepatitis B virus (HBV) reactivation is a fatal complication in patients who receive chemotherapy or immunosuppressive therapy. We examined the effect of preventive entecavir (ETV), a new nucleoside analogue on HBV reactivation during chemotherapy or immunosuppressive therapy. METHODS Between February 2007 and September 2009, sixteen nucleoside analogue treatment-naive patients with chronic HBV infection (HB surface antigen [HBsAg] positive) who required chemotherapy or immunosuppressive therapy were enrolled. Referring to some guidelines, the patients received preventive ETV to reduce incidence of HBV reactivation, and were closely monitored for HBV markers. RESULTS HBV reactivation did not occur in any of the 16 patients and the indispensable treatments for their underlying diseases could be continued. However, HBV relapsed after preventive ETV was discontinued in 2 patients. CONCLUSIONS This study suggests that ETV is a useful option for preventing HBV reactivation in patients with chronic HBV infection.


The American Journal of Gastroenterology | 2009

Repeat Radiofrequency Ablation Provides Survival Benefit in Patients With Intrahepatic Distant Recurrence of Hepatocellular Carcinoma

Yusuke Okuwaki; Takahide Nakazawa; Shigehiro Kokubu; Hisashi Hidaka; Yoshiaki Tanaka; Juichi Takada; Masaaki Watanabe; Akitaka Shibuya; Tsutomu Minamino; Katsunori Saigenji

OBJECTIVES:Intrahepatic distant recurrence (IDR) of hepatocellular carcinoma (HCC) after curative treatment occurs frequently and influences the prognoses. The aim of this study was to determine prognostic factors affecting survival after IDR and the optimum therapy for IDR.METHODS:A total of 115 patients with a single small primary HCC who had complete radiofrequency (RF) ablation were enrolled in this study. The prognostic factors and the optimum therapy affecting survival were statistically analyzed among patients with IDRs.RESULTS:IDRs were observed in 59 (51.3%) patients with the median observation period of 19.6 months. The cumulative rates of IDRs were 11.8, 53.9, and 75.8% at 1, 3, and 5 years, respectively. IDR nodules were present as a single nodule in 38 patients and as multiple nodules in 21 patients. In all, 23 patients died during the follow-up. A total of 30 patients were treated with RF ablation, and 27 were treated with transcatheter arterial chemoembolization (TACE). The overall cumulative survival rates after IDRs were 92.7, 55.4, and 43.7% at 1, 3, and 5 years, respectively. A multivariate analysis showed that treatment with RF ablation for IDR was a significant favorable prognostic factor after IDR (hazard ratio: 0.167, 95% confidence interval: 0.048−0.584, P=0.005). In a comparison of survival after IDR between patients treated with RF ablation and TACE, who were comparable with clinical and tumoral characteristics, the cumulative survival rate of patients treated with RF ablation was significantly higher than that of those treated with TACE (77.2 vs 28.5% at 3 years). The cumulative survival rates obtained from the initial RF ablation of the patients with IDRs treated with repeat RF ablation were similar to those of recurrence-free patients.CONCLUSIONS:Repeat RF ablation should be attempted for IDR as much as possible despite tumor multiplicity for survival benefit; by reducing the need, it will help solve the problem of the current shortage of donors for liver transplantations.


Oncology | 2007

Potential Prognostic Benefits of Radiotherapy as an Initial Treatment for Patients with Unresectable Advanced Hepatocellular Carcinoma with Invasion to Intrahepatic Large Vessels

Takahide Nakazawa; Shigeru Adachi; Masashi Kitano; Yoshinori Isobe; Shigehiro Kokubu; Hisashi Hidaka; Koji Ono; Yusuke Okuwaki; Masaaki Watanabe; Akitaka Shibuya; Katsunori Saigenji

Objectives: To examine the efficacy and prognostic benefits of radiotherapy (RT) in patients who have unresectable advanced hepatocellular carcinoma (HCC) with invasion to intrahepatic large vessels (IHLVs). Methods: Sixty-eight patients who had advanced HCC with invasion to IHLVs were studied. Thirty-two consecutive patients initially received 3-dimensional conformal RT for HCC invasion to IHLVs. Tumor response, prognostic factors, and survival were studied in the patients given RT. Prognostic factors and survival were assessed in the study group as a whole. Data were analyzed using the Kaplan-Meier method, univariate analysis, and a Cox model. Results: The rate of objective response to RT was 48%. Predictors of survival in the patients who received RT were a hepatic function of Child-Pugh class A (p = 0.0263) and a response to RT (p = 0.0121). In the study group as a whole, independent predictors of survival in a Cox model were multinodular HCC (p = 0.007), inferior vena caval invasion (p = 0.001), a serum α-fetoprotein level of >1,000 ng/ml (p = 0.032), and the performance of RT (p < 0.001). Notably, the median survival of the nonresponders to RT (n = 15) was significantly longer than that of the patients who received no treatment for HCC (n = 21; 7.0 vs. 3.4 months, p = 0.0014). Conclusion: RT is considered an effective initial treatment for HCC invasion to IHLVs, and may offer survival benefits, even in nonresponders, because of the induction of stable disease.


Liver International | 2011

Re-appearance of hepatitis B virus following therapy with rituximab for lymphoma is not rare in Japanese patients with past hepatitis B virus infection.

Masaaki Watanabe; Akitaka Shibuya; Yuhko Tsunoda; Mikio Danbara; Ryuji Ishii; Manabu Ohsaka; Juichi Takada; Yoshiaki Tanaka; Yusuke Okuwaki; Tsutomu Minamino; Hisashi Hidaka; Takahide Nakazawa; Ryouichi Horie; Masaaki Higashihara; Wasaburo Koizumi

Background and aim: De novo hepatitis B virus (HBV)‐related hepatitis is a well‐known fatal complication following chemo‐immunosuppressive therapy in patients with past HBV infection (HB surface antigen and serum HBV DNA negative, but HB core antibody and/or HB surface antibody positive). This research was conducted to evaluate the incidence of and clinical features associated with re‐appearance of serum HBV DNA following chemo‐immunosuppressive therapy in Japanese patients with past HBV infection.


Journal of Gastroenterology and Hepatology | 2014

Radiotherapy for patients with unresectable advanced hepatocellular carcinoma with invasion to intrahepatic large vessels: Efficacy and outcomes

Yoshiaki Tanaka; Takahide Nakazawa; Shouko Komori; Hisashi Hidaka; Yusuke Okuwaki; Juichi Takada; Masaaki Watanabe; Akitaka Shibuya; Tsutomu Minamino; Hajime Yamamoto; Shigehiro Kokubu; Kazushige Hayakawa; Wasaburo Koizumi

To examine the efficacy and outcomes of radiotherapy (RT) in patients who have hepatocellular carcinoma with invasion to intrahepatic large vessels (IHLVs).


Case Reports in Oncology | 2010

Rapid Regression of Advanced Hepatocellular Carcinoma Associated with Elevation of Des-Gamma-Carboxy Prothrombin after Short-Term Treatment with Sorafenib – A Report of Two Cases

Takahide Nakazawa; Hisashi Hidaka; Akitaka Shibuya; Wasaburo Koizumi

Background: Sorafenib is the first molecular-targeted agent that is effective for advanced hepatocellular carcinoma (HCC), with prolongation of survival. However, a complete response is very rare, and rapid regression of HCC after short-term treatment with sorafenib has not been reported previously. Case Reports: We describe 2 patients with advanced multiple HCC who received sorafenib for short periods of 1 or 2 weeks, respectively. Longer treatment was precluded by the development of hepatic failure as an adverse event of sorafenib. Results: HCC rapidly regressed, and both patients had a partial response (PR), despite short-term treatment. Furthermore, an early elevation of des-gamma-carboxy prothrombin (DCP) was temporarily seen in both patients, with no elevation of alpha-fetoprotein. Conclusions: Sorafenib can induce rapid regression of advanced HCC even after short-term treatment, and the initial response of HCC was identical in both patients. Since early elevation of DCP was observed in our patients with PR, DCP might be a predictive biomarker of anti-tumor response. Further studies are required to clarify the mechanisms underlying the effectiveness of sorafenib, including the alteration of DCP.

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