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Featured researches published by Masahiro Kenjo.


International Journal of Radiation Oncology Biology Physics | 1999

Optimum fractionation for high-dose-rate endoesophageal brachytherapy following external irradiation of early stage esophageal cancer

Yukio Akagi; Yutaka Hirokawa; Masayuki Kagemoto; Kanji Matsuura; Atsushi Ito; Masahiro Kenjo; Hiroshi Kiriu; Katsuhide Ito

PURPOSE To establish the optimum fractionation for high-dose-rate (HDR) endoesophageal brachytherapy (EBT) for early stage esophageal cancer from retrospective data of patients treated with different HDR schedules following external beam irradiation (EBI). METHODS AND MATERIALS The study population consisted of 35 consecutive early stage esophageal cancer patients who received EBI to the mediastinum, plus EBT, between May 1992 and November 1995 at the Hiroshima University Medical Center and Hiroshima City Hospital. All patients were treated with EBI, with doses ranging from 50 to 61 Gy. The spinal cord was spared after 44-45 Gy. HDR EBT was performed using a double-balloon applicator in conjunction with an Ir-192 remote afterloading system. One group of 10 patients was given a weekly endoesophageal boost of 4 or 5 Gy at a distance of 5 mm from the applicator surface over a period of 1-2 weeks. Another group of 25 patients was treated with 4 or 5 endoesophageal boosts with a fraction dose of either 2.5 or 2 Gy for 1 week. The linear quadratic (LQ) formula was used to calculate the biologically effective dose (BED) for tumor (Gy10) and esophageal mucosa (Gy3); Gy10 means alpha/beta equals 10 Gy, and Gy3 means alpha/beta equals 3 Gy. The Kaplan-Meier method was used to calculate the local control and late complication rates, while the Cox-Mantel test was used to evaluate statistical significance (p < 0.01). RESULTS Nine (26%) of the 35 patients recurred locally and 7 (20%) had late complications (esophageal ulcer grade by RTOG/EORTC criteria > 1). The 5-year overall survival, local control, and late complication rates were 38%, 57%, and 26%, respectively. The probability of local recurrence was not affected by the treatment parameters. Results from the LQ formula significantly correlate with data on late complications. A BED > 134 Gy3 and a fraction number = < 3 were associated with late complications (grade > 1). BED analysis showed that the fractionation dose should be decreased to 2.5 or 2.0 Gy at a distance of 5 mm from the applicator surface, and the number of doses increased to 4 or 5, respectively, to yield a satisfactory BED (< 134 Gy3). CONCLUSION A significant reduction in endoesophageal brachytherapy dose per fraction is necessary to reduce late complications. Our current treatment protocol for early-stage esophageal cancer consists of EBI of 60 Gy followed by 4 EBT doses at a fraction dose of 2.5 Gy applied over 1 week.


Journal of Gastroenterology and Hepatology | 2013

Stereotactic body radiation therapy combined with transcatheter arterial chemoembolization for small hepatocellular carcinoma

Yohji Honda; Tomoki Kimura; Tomoki Kobayashi; Takayuki Fukuhara; Keiichi Masaki; Takashi Nakahara; Noriaki Naeshiro; Atsushi Ono; Daisuke Miyaki; Yuko Nagaoki; Tomokazu Kawaoka; Shintaro Takaki; Akira Hiramatsu; Masaki Ishikawa; Hideaki Kakizawa; Masahiro Kenjo; Shoichi Takahashi; Kazuo Awai; Yasushi Nagata; Kazuaki Chayama

To compare the tumor control and safety of stereotactic body radiation therapy (SBRT) combined with transcatheter arterial chemoembolization (TACE) for small, solitary, and hypervascular hepatocellular carcinoma (HCC) with TACE alone.


International Journal of Radiation Oncology Biology Physics | 2012

Prospective multi-institutional study of definitive radiotherapy with high-dose-rate intracavitary brachytherapy in patients with nonbulky (<4-cm) stage i and II uterine cervical cancer (JAROG0401/JROSG04-2)

Takafumi Toita; Shingo Kato; Yuzuru Niibe; Tatsuya Ohno; Tomoko Kazumoto; Takeshi Kodaira; Masaaki Kataoka; Naoto Shikama; Masahiro Kenjo; Sunao Tokumaru; Chikako Yamauchi; Osamu Suzuki; Hideyuki Sakurai; Hodaka Numasaki; Teruki Teshima; Masahiko Oguchi; Yoshikazu Kagami; Takashi Nakano; Masahiro Hiraoka; Norio Mitsuhashi

PURPOSE To determine the efficacy of a definitive radiotherapy protocol using high-dose-rate intracavitary brachytherapy (HDR-ICBT) with a low cumulative dose schedule in nonbulky early-stage cervical cancer patients, we conducted a prospective multi-institutional study. METHODS AND MATERIALS Eligible patients had squamous cell carcinoma of the intact uterine cervix, Federation of Gynecologic Oncology and Obstetrics (FIGO) stages Ib1, IIa, and IIb, tumor size <40 mm in diameter (assessed by T2-weighted magnetic resonance imaging), and no pelvic/para-aortic lymphadenopathy. The treatment protocol consisted of whole-pelvis external beam radiotherapy (EBRT) of 20 Gy/10 fractions, pelvic EBRT with midline block of 30 Gy/15 fractions, and HDR-ICBT of 24 Gy/4 fractions (at point A). The cumulative biologically effective dose (BED) was 62 Gy(10) (α/β = 10) at point A. The primary endpoint was the 2-year pelvic disease progression-free (PDPF) rate. All patients received a radiotherapy quality assurance review. RESULTS Between September 2004 and July 2007, 60 eligible patients were enrolled. Thirty-six patients were assessed with FIGO stage Ib1; 12 patients with stage IIa; and 12 patients with stage IIb. Median tumor diameter was 28 mm (range, 6-39 mm). Median overall treatment time was 43 days. Median follow-up was 49 months (range, 7-72 months). Seven patients developed recurrences: 3 patients had pelvic recurrences (2 central, 1 nodal), and 4 patients had distant metastases. The 2-year PDPF was 96% (95% confidence interval [CI], 92%-100%). The 2-year disease-free and overall survival rates were 90% (95% CI, 82%-98%) and 95% (95% CI, 89%-100%), respectively. The 2-year late complication rates (according to Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer of Grade ≥ 1) were 18% (95% CI, 8%-28%) for large intestine/rectum, 4% (95% CI, 0%-8%) for small intestine, and 0% for bladder. No Grade ≥ 3 cases were observed for genitourinary/gastrointestinal late complications. CONCLUSIONS These results suggest that definitive radiotherapy using HDR-ICBT with a low cumulative dose schedule (BED, 62 Gy(10) at point A) can provide excellent local control without severe toxicity in nonbulky (<4-cm) early-stage cervical cancer.


Neuro-oncology | 2008

Primary central nervous system lymphoma in Japan: changes in clinical features, treatment, and prognosis during 1985-2004.

Yuta Shibamoto; Hiroyuki Ogino; Gen Suzuki; Mitsuhiro Takemoto; Norio Araki; Koichi Isobe; Emiko Tsuchida; Katsumasa Nakamura; Masahiro Kenjo; Kazunori Suzuki; Masako Hosono; Sunao Tokumaru; Shunichi Ishihara; Eriko Kato; Noriko; Naofumi Hayabuchi

We have conducted nationwide surveys of primary central nervous system lymphoma (PCNSL) treated since 1985. In the present study, we newly collected data between 2000 and 2004 and investigated changes in clinical features and outcome over time. A total of 739 patients with histologically proven PCNSL under going radiotherapy were analyzed. Seventeen institutions were surveyed, and data on 131 patients were collected. These data were compared with updated data that were previously obtained for 466 patients treated during 1985-1994 and 142 patients treated during 1995-1999. Recent trends toward decrease in male/female ratio, increase in aged patients, and increase in patients with multiple lesions were seen. Regarding treatment, decrease in attempts at surgical tumor removal and increases in use of systemic chemotherapy and methotrexate (MTX)-containing regimens were observed. The median survival time was 18, 29, and 24 months for patients seen during 1985-1994, 1995-1999, and 2000-2004, respectively, and the respective 5-year survival rates were 15%, 30%, and 30%. In groups seen during 1995-1999 and during 2000-2004, patients who received systemic or MTX-containing chemotherapy had better prognosis than those who did not. Multivariate analysis of all patients seen during 1985-2004 suggested the usefulness of MTX-containing chemotherapy as well as the importance of age, lactate dehydrogenase level, and tumor multiplicity as prognostic factors. Thus, this study revealed several notable changes in clinical features of PCNSL patients. The prognosis improved during the last 10 years. Advantage of radiation plus chemotherapy, especially MTX-containing chemotherapy, over radiation alone was suggested.


Hepatology Research | 2015

Stereotactic body radiotherapy for patients with small hepatocellular carcinoma ineligible for resection or ablation therapies

Tomoki Kimura; Shigeo Takahashi; I. Takahashi; Ikuno Nishibuchi; Y. Doi; Masahiro Kenjo; Yuji Murakami; Yohji Honda; Hideaki Kakizawa; Kazuo Awai; Kazuaki Chayama; Yasushi Nagata

To evaluate the efficacy and safety of stereotactic body radiotherapy (SBRT) in patients with small hepatocellular carcinoma (HCC) who were ineligible for resection or ablation therapies.


International Journal of Radiation Oncology Biology Physics | 2009

Radiation Therapy for Esophageal Cancer in Japan: Results of the Patterns of Care Study 1999–2001

Masahiro Kenjo; Takashi Uno; Yuji Murakami; Yasushi Nagata; Masahiko Oguchi; Susumu Saito; Hodaka Numasaki; Teruki Teshima; Michihide Mitsumori

PURPOSE To describe patient characteristics and the process of radiotherapy (RT) for patients with esophageal cancer treated between 1999 and 2001 in Japan. METHODS AND MATERIALS The Japanese Patterns of Care Study (PCS) Working Group conducted a third nationwide survey of 76 institutions. Detailed information was accumulated on 621 patients with thoracic esophageal cancer who received RT. RESULTS The median age of patients was 68 years. Eighty-eight percent were male, and 12% were female. Ninety-nine percent had squamous cell carcinoma histology. Fifty-five percent had the main lesion in the middle thoracic esophagus. Fourteen percent had clinical Stage 0-I disease, 32% had Stage IIA-IIB, 43% had Stage III, and 10% had Stage IV disease. Chemotherapy was given to 63% of patients; 39% received definitive chemoradiotherapy (CRT) without surgery and 24% pre- or postoperative CRT. Sixty-two percent of the patients aged > or =75 years were treated with RT only. Median total dose of external RT was 60 Gy for definitive CRT patients, 60 Gy for RT alone, and 40 Gy for preoperative CRT. CONCLUSIONS This PCS describes general aspects of RT for esophageal cancer in Japan. Squamous cell carcinoma accounted for the majority of patients. The standard total external RT dose for esophageal cancer was higher in Japan than in the United States. Chemoradiotherapy had become common for esophageal cancer treatment, but patients aged > or =75 years were more likely to be treated by RT only.


International Journal of Radiation Oncology Biology Physics | 2012

Functional Image-Guided Radiotherapy Planning in Respiratory-Gated Intensity-Modulated Radiotherapy for Lung Cancer Patients With Chronic Obstructive Pulmonary Disease

Tomoki Kimura; Ikuno Nishibuchi; Yuji Murakami; Masahiro Kenjo; Yuko Kaneyasu; Yasushi Nagata

PURPOSE To investigate the incorporation of functional lung image-derived low attenuation area (LAA) based on four-dimensional computed tomography (4D-CT) into respiratory-gated intensity-modulated radiotherapy (IMRT) or volumetric modulated arc therapy (VMAT) in treatment planning for lung cancer patients with chronic obstructive pulmonary disease (COPD). METHODS AND MATERIALS Eight lung cancer patients with COPD were the subjects of this study. LAA was generated from 4D-CT data sets according to CT values of less than than -860 Hounsfield units (HU) as a threshold. The functional lung image was defined as the area where LAA was excluded from the image of the total lung. Two respiratory-gated radiotherapy plans (70 Gy/35 fractions) were designed and compared in each patient as follows: Plan A was an anatomical IMRT or VMAT plan based on the total lung; Plan F was a functional IMRT or VMAT plan based on the functional lung. Dosimetric parameters (percentage of total lung volume irradiated with ≥20 Gy [V20], and mean dose of total lung [MLD]) of the two plans were compared. RESULTS V20 was lower in Plan F than in Plan A (mean 1.5%, p = 0.025 in IMRT, mean 1.6%, p = 0.044 in VMAT) achieved by a reduction in MLD (mean 0.23 Gy, p = 0.083 in IMRT, mean 0.5 Gy, p = 0.042 in VMAT). No differences were noted in target volume coverage and organ-at-risk doses. CONCLUSIONS Functional IGRT planning based on LAA in respiratory-guided IMRT or VMAT appears to be effective in preserving a functional lung in lung cancer patients with COPD.


Hepatology Research | 2015

Role of 3-D conformal radiotherapy for major portal vein tumor thrombosis combined with hepatic arterial infusion chemotherapy for advanced hepatocellular carcinoma

Hatsue Fujino; Tomoki Kimura; Daisuke Miyaki; Tomokazu Kawaoka; Hiromi Kan; Takayuki Fukuhara; Tomoki Kobayashi; Noriaki Naeshiro; Yohji Honda; Masataka Tsuge; Akira Hiramatsu; Michio Imamura; Yoshiiku Kawakami; Hideyuki Hyogo; Shoichi Takahashi; Rika Yoshimatsu; Takuji Yamagami; Masahiro Kenjo; Yasushi Nagata; Kazuo Awai; Kazuaki Chayama

To evaluate the response, survival and safety on 3‐D conformal radiotherapy (3D‐CRT) for major portal vein tumor thrombosis (PVTT) combined with hepatic arterial infusion chemotherapy (HAIC) for advanced hepatocellular carcinoma (HCC).


Progress in neurological surgery | 2009

Quality of Life of Extremely Long-Time Germinoma Survivors Mainly Treated with Radiotherapy

Kazuhiko Sugiyama; Fumiyuki Yamasaki; Kaoru Kurisu; Masahiro Kenjo

PURPOSE To assess the quality of life (QOL) of extremely long-time survivors with germinoma mainly treated with radiotherapy. PATIENTS AND METHODS We enrolled 52 of 68 patients who received radiotherapy between 1968 and 1995 at our hospital. They were 41 males and 11 females; the tumor location was pineal in 20, neurohypophyseal in 15, pineal and neurohypophyseal in 11 patients; in 6 it was located in another region. All underwent radiotherapy; the median dose was 48.2 (range 40.0-60.2) Gy. The median follow-up period was 226 (range 0-448) months. The clinical outcome and QOL were evaluated retrospectively. RESULTS In 6 patients, the tumor recurred; 6 other patients developed second tumors while in complete remission from the first tumor. The main cause of 12 deaths was complications due to primary tumor invasion, the initial treatment, or tumor recurrence rather than tumor progression. The 10-, 20-, and 30-year actuarial survival rate was 83.6, 77.5, and 64.2%, respectively. Of 44 patients, 6 were married and 3 males with solitary pineal tumors were fathers. Among 32 patients, 14 had, or had not, graduated from high school; the other 18 went on to higher education. Twenty-one patients had no occupation; 7 of 11 formerly employed patients had left their jobs. CONCLUSION Radiotherapy delivered between 1968 and 1995 to patients with germinoma yielded satisfactory outcomes but a decline in the QOL.


Japanese Journal of Clinical Oncology | 2010

High-dose-rate Intracavitary Brachytherapy Combined with External Beam Radiotherapy for Stage IIIb Adenocarcinoma of the Uterine Cervix in Japan: A Multi-Institutional Study of Japanese Society of Therapeutic Radiology and Oncology 2006–2007 (Study of JASTRO 2006–2007)

Yuzuru Niibe; Masahiro Kenjo; Hiroshi Onishi; Yoshihiro Ogawa; Tomoko Kazumoto; Ichiro Ogino; Kayoko Tsujino; Yoko Harima; Takeo Takahashi; Akira Anbai; Emiko Tsuchida; Takafumi Toita; Mitsuhiro Takemoto; Hideomi Yamashita; Kazushige Hayakawa

OBJECTIVE The current study was a retrospective questionnaire survey of stage IIIb adenocarcinoma of the uterine cervix treated with high-dose-rate intracavitary brachytherapy combined with external beam radiation therapy in Japan aimed to investigate the optimal dose on the basis of the biological effective dose and prognostic factors. METHODS Between 1990 and 2000, 61 patients with stage IIIb adenocarcinoma of the uterine cervix underwent high-dose-rate intracavitary brachytherapy combined with external beam radiation therapy in 19 major hospitals in Japan. This retrospective questionnaire survey was performed by mail including survey charts to be fulfilled by radiation oncologists in these 19 major hospital. Fifty had only adenocarcinoma components and 11 had adenosquamous cell carcinoma components. All patients were treated with high-dose-rate intracavitary brachytherapy combined with external beam radiation therapy. Total biological effective dose (T-BED(10)) was calculated from the sum of the biological effective doses of the external beam radiation therapy and the intracavitary brachytherapy. Thirty-two patients underwent chemotherapy. RESULTS The 5-year overall survival rate of all patients was 20.2%. Stratified by total biological effective dose, the 5-year overall survival rate was 0% for T-BED(10) <75 Gy, 24.7% for T-BED(10) between 75 and 100 Gy and 0% for T-BED(10) >110 Gy (P = 0.15). Stratified by histopathology, the 5-year overall survival rate was 22.1% for adenocarcinoma and 13.6% for adenosquamous cell carcinoma (P = 0.43). Stratified by chemotherapy, the 5-year overall survival rate was 20.3% in patients who received chemotherapy and 20.4% in patients who did not receive chemotherapy (P = 0.96). CONCLUSIONS The 5-year overall survival rate of stage IIIb adenocarcinoma of the uterine cervix in this retrospective questionnaire survey was 20.2%. The optimal T-BED(10) and evident prognostic factors were not clear from this questionnaire survey.

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Y. Doi

Hiroshima University

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Masahiko Oguchi

Japanese Foundation for Cancer Research

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