A. Ohkawa
University of Tsukuba
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Featured researches published by A. Ohkawa.
Journal of Thoracic Oncology | 2012
Yoshiko Oshiro; Masashi Mizumoto; Toshiyuki Okumura; Takayuki Hashimoto; Nobuyoshi Fukumitsu; A. Ohkawa; Ayae Kanemoto; Haruko Hashii; Toshiki Ohno; Takeji Sakae; Koji Tsuboi; Hideyuki Sakurai
Introduction: This study was performed retrospectively to evaluate the outcome of patients with stage III non-small cell lung cancer (NSCLC) after proton beam therapy (PBT) alone. Methods: The subjects were 57 patients with histologically confirmed NSCLC (stage IIIA/IIIB: 24/33) who received PBT without concurrent chemotherapy. The cohort included 32 cases of squamous cell carcinoma, 18 adenocarcinoma, and 7 non-small cell carcinoma. Lymph node metastases were N0 7, N1 5, N2 30, and N3 15. Planned total doses ranged from 50 to 84.5 GyE (median, 74 GyE). Results: Planned treatment was completed in 51 patients (89%). At the time of analysis, 20 patients were alive, and the median follow-up periods were 16.2 months for all patients and 22.2 months for survivors. The median overall survival period was 21.3 months (95% confidence interval: 14.2–28.4 months), and the 1- and 2-year overall survival rates were 65.5% (52.9–78.0%) and 39.4% (25.3–53.5%), respectively. Disease progression occurred in 38 patients, and the 1- and 2-year progression-free survival rates were 36.2% (23.1–49.4%) and 24.9% (12.7–37.2%), respectively. Local recurrence was observed in 13 patients, and the 1- and 2-year local control rates were 79.1% (66.8–91.3%) and 64.1% (47.5–80.7%), respectively. Grade ≥3 lung toxicity was seen in six patients, esophageal toxicity occurred at grade ⩽2, and there was no cardiac toxicity. Conclusion: The prognosis of patients with unresectable stage III NSCLC is poor without chemotherapy. Our data suggest that high-dose PBT is beneficial and tolerable for these patients.
International Journal of Radiation Oncology Biology Physics | 2012
Masashi Mizumoto; Toshiyuki Okumura; Takayuki Hashimoto; Kuniaki Fukuda; Yoshiko Oshiro; Nobuyoshi Fukumitsu; Masato Abei; Atsushi Kawaguchi; Yasutaka Hayashi; A. Ohkawa; Haruko Hashii; Ayae Kanemoto; Takashi Moritake; Eriko Tohno; Koji Tsuboi; Takeji Sakae; Hideyuki Sakurai
PURPOSE Our previous results for treatment of hepatocellular carcinoma with proton beam therapy (PBT) revealed excellent local control. In this study, we focused on the impact of PBT on normal liver function. METHODS AND MATERIALS The subjects were 259 patients treated with PBT at the University of Tsukuba between January 2001 and December 2007. We evaluated the Child-Pugh score pretreatment, on the final day of PBT, and 6, 12, and 24 months after treatment with PBT. Patients who had disease progression or who died with tumor progression at each evaluation point were excluded from the analysis to rule out an effect of tumor progression. An increase in the Child-Pugh score of 1 or more was defined as an adverse event. RESULTS Of the 259 patients, 241 had no disease progression on the final day of PBT, and 91 had no progression within 12 months after PBT. In univariate analysis, the percentage volumes of normal liver receiving at least 0, 10, 20, and 30 GyE in PBT (V0, 10, 20, and 30) were significantly associated with an increase of Child-Pugh score at 12 months after PBT. Of the 91 patients evaluated at 12 months, 66 had no increase of Child-Pugh score, 15 had a 1-point increase, and 10 had an increase of ≥2 points. For the Youden index, the optimal cut-offs for V0, V10, V20, and V30 were 30%, 20%, 26%, and 18%, respectively. CONCLUSION Our findings indicate that liver function after PBT is significantly related to the percentage volume of normal liver that is not irradiated. This suggests that further study of the relationship between liver function and PBT is required.
Clinical Lung Cancer | 2014
Ayae Kanemoto; Toshiyuki Okumura; Hitoshi Ishikawa; Masashi Mizumoto; Yoshiko Oshiro; Koichi Kurishima; Shinsuke Homma; Takayuki Hashimoto; A. Ohkawa; Haruko Numajiri; Toshiki Ohno; Takashi Moritake; Koji Tsuboi; Takeji Sakae; Hideyuki Sakurai
INTRODUCTION This study was conducted to determine disease control rates and prognostic factors associated with recurrence of centrally and peripherally located stage I NSCLC treated using high-dose PBT. PATIENTS AND METHODS Seventy-four patients with 80 centrally or peripherally located stage I NSCLCs were treated with PBT. A protocol using 72.6 Gy (RBE) in 22 fractions was used for centrally located tumors, and 66 Gy (RBE) in 10 or 12 fractions was used for peripherally located tumors. Data were collected and control rates and prognostic factors for recurrence were evaluated retrospectively. RESULTS The median follow-up period was 31.0 months. The overall survival, disease-specific survival, and progression-free survival rates were 76.7%, 83.0%, and 58.6% at 3 years, respectively. Disease recurrence was noted in 30 patients and local recurrence of 11 tumors occurred. The 3-year local control rate was 86.2% for stage IA tumors and 67.0% for stage IB tumors. Radiation dose was identified as a significant prognostic factor for disease recurrence and local recurrence. Tumor diameter and age were only significantly associated with disease recurrence. The 3-year local control rate was 63.9% for centrally located tumors irradiated with 72.6 Gy (RBE) and 88.4% for peripherally located tumors irradiated with 66 Gy (RBE). CONCLUSION Radiation dose was shown to be the most significant prognostic factor for tumor control in stage I NSCLC treated using high-dose PBT. Tumor diameter was not significant for local control. Further evaluation of PBT for centrally located tumors is warranted.
Journal of Gastroenterology and Hepatology | 2015
A. Ohkawa; Masashi Mizumoto; Hitoshi Ishikawa; Masato Abei; Kuniaki Fukuda; Takayuki Hashimoto; Takeji Sakae; Koji Tsuboi; Toshiyuki Okumura; Hideyuki Sakurai
Treatment for unresectable intrahepatic cholangiocarcinoma (ICC) has not been established. The aim of the study was to evaluate the outcome of proton beam therapy (PBT) for patients with unresectable ICC.
International Journal of Radiation Oncology Biology Physics | 2012
Nobuyoshi Fukumitsu; Toshiyuki Okumura; Masashi Mizumoto; Yoshiko Oshiro; Takayuki Hashimoto; Ayae Kanemoto; Haruko Hashii; A. Ohkawa; Takashi Moritake; Koji Tsuboi; Keiji Tabuchi; Tetsuro Wada; Akira Hara; Hideyuki Sakurai
International Journal of Radiation Oncology Biology Physics | 2012
Takayuki Hashimoto; Hiroichi Ishikawa; Toshiyuki Okumura; Hirokazu Makishima; Toshiki Ohno; Ayae Kanemoto; Haruko Hashii; A. Ohkawa; Masashi Mizumoto; Hideyuki Sakurai
International Journal of Radiation Oncology Biology Physics | 2010
Haruko Hashii; Takayuki Hashimoto; Tomonori Isobe; A. Ohkawa; T. Komiya; Masahiro Hanmura; Takeji Sakae; Tetsuo Nishimura; Kazutaka Aonuma; Hideyuki Sakurai
International Journal of Radiation Oncology Biology Physics | 2011
Masashi Mizumoto; Koji Tsuboi; Toshiyuki Okumura; Takayuki Hashimoto; Yoshiko Oshiro; Nobuyoshi Fukumitsu; Yasutaka Hayashi; A. Ohkawa; Takeji Sakae; Hideyuki Sakurai
International Journal of Radiation Oncology Biology Physics | 2011
Yoshiko Oshiro; Toshiyuki Okumura; Masashi Mizumoto; Takayuki Hashimoto; Nobuyoshi Fukumitsu; A. Ohkawa; Ayae Kanemoto; Haruko Hashii; Koji Tsuboi; Hideyuki Sakurai
International Journal of Radiation Oncology Biology Physics | 2011
Takayuki Hashimoto; Toshiyuki Okumura; Ayae Kanemoto; Haruko Hashii; A. Ohkawa; Yoshiko Oshiro; Masashi Mizumoto; Nobuyoshi Fukumitsu; Koji Tsuboi; Hideyuki Sakurai