Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Masaru Wakatsuki is active.

Publication


Featured researches published by Masaru Wakatsuki.


Journal of Radiation Research | 2014

Clinical trial of carbon ion radiotherapy for gynecological melanoma

Kumiko Karasawa; Masaru Wakatsuki; Shingo Kato; Hiroki Kiyohara; Tadashi Kamada

Carbon ion radiotherapy (C-ion RT) is an advanced modality for treating malignant melanoma. After we treated our first case of gynecological melanoma using C-ion RT in November 2004, we decided to conduct a clinical trial to evaluate its usefulness for the treatment of gynecological melanoma. The eligibility criteria for enrollment in this study were histologically proven malignant melanoma of the gynecological regions with lymph node metastasis remaining in the inguinal and pelvic regions. The small pelvic space, including the GTV and the metastatic lymph node, was irradiated with up to a total dose of 36 GyE followed by a GTV boost of up to a total dose of 57.6 GyE or 64 GyE in 16 fractions. A series of 23 patients were treated between November 2004 and October 2012. Patient age ranged from 51–80 with a median of 71. Of the tumor sites, 14 were located in the vagina, 6 in the vulva, and 3 in the cervix uteri. Of the 23 patients, 22 were irradiated with up to a total dose of 57.6 GyE, and 1 patient was irradiated with up to a total dose of 64 GyE. Chemotherapy and interferon-β were also used to treat 11 of the patients. Acute and late toxicities of Grade 3 or higher were observed in 1 patient treated with concurrent interferon-β. The median follow-up time was 17 months (range, 6–53 months). There was recurrence in 14 patients, and the 3-year local control and overall survival rates were 49.9% and 53.0%, respectively. C-ion RT may become a non-invasive treatment option for gynecological melanoma.


PLOS ONE | 2015

Clinical trial of prophylactic extended-field carbon-ion radiotherapy for locally advanced uterine cervical cancer (protocol 0508).

Masaru Wakatsuki; Shingo Kato; Hiroki Kiyohara; Tatsuya Ohno; Kumiko Karasawa; Tomoaki Tamaki; Ken Ando; Hirohiko Tsujii; Takashi Nakano; Tadashi Kamada; Makio Shozu

To evaluate the efficacy and the toxicity of prophylactic extended-field carbon-ion radiotherapy (C-ion RT, Protocol 0508) for locally advanced squamous cell carcinoma of the uterine cervix in phase I / II clinical trial. Between May 2006 and January 2012, 26 patients of Protocol 0508 were treated with C-ion RT. The numbers of patients with stage IIB, IIIB, and IVA disease were 13, 11, and 2, respectively. Twenty patients had pelvic lymph node metastases. Median tumor size was 6.1 cm (range, 4.0–10.0 cm). The treatment consisted of extended-field irradiation of 39.0 gray equivalents (GyE) in 13 fractions, and additional 15.0 GyE in 5 fractions was given to the gross tumor volume (GTV) and surrounding tissues. With regard to local boost, 18.0 GyE in 2 fractions was given to GTV only. Total dose to the cervical tumor was 72.0 GyE over 20 fractions. The median follow-up period was 37 months. Twenty-one patients had grade 1 or 2 acute gastrointestinal toxicity, but all patients completed the treatment on schedule. There were no grade 3 or higher late complications, with 8 patients having grade 1 or 2 toxicities, 1 had grade 2 gastrointestinal toxicity and 2 had grade 2 genitourinary toxicity. Four patients (15.4%) developed local recurrence, and 8 patients (30.8%) had distant metastases. The 2-year local control rate, progression-free survival rate and overall survival rate were 83.6%, 61.5% and 73.1%, respectively. There were no severe acute or late complications in this trial. Prophylactic extended-field C-ion RT for locally advanced squamous cell carcinoma of the uterine cervix was a safe treatment. Although the number of patients in this study was small, the results support further investigations to confirm the therapeutic efficacy and to avoid or reduce toxicity. Trial Registration UMIN-CTR UMIN000016169


Journal of Radiation Research | 2016

Recommendations for high-risk clinical target volume definition with computed tomography for three-dimensional image-guided brachytherapy in cervical cancer patients

Tatsuya Ohno; Masaru Wakatsuki; Takafumi Toita; Yuko Kaneyasu; Ken Yoshida; Shingo Kato; Noriko Li; Sunao Tokumaru; Hitoshi Ikushima; Takashi Uno; Shin-ei Noda; Tomoko Kazumoto; Yoko Harima

Abstract Our purpose was to develop recommendations for contouring the computed tomography (CT)-based high-risk clinical target volume (CTVHR) for 3D image-guided brachytherapy (3D-IGBT) for cervical cancer. A 15-member Japanese Radiation Oncology Study Group (JROSG) committee with expertise in gynecological radiation oncology initiated guideline development for CT-based CTVHR (based on a comprehensive literature review as well as clinical experience) in July 2014. Extensive discussions occurred during four face-to-face meetings and frequent email communication until a consensus was reached. The CT-based CTVHR boundaries were defined by each anatomical plane (cranial–caudal, lateral, or anterior–posterior) with or without tumor progression beyond the uterine cervix at diagnosis. Since the availability of magnetic resonance imaging (MRI) with applicator insertion for 3D planning is currently limited, T2-weighted MRI obtained at diagnosis and just before brachytherapy without applicator insertion was used as a reference for accurately estimating the tumor size and topography. Furthermore, utilizing information from clinical examinations performed both at diagnosis and brachytherapy is strongly recommended. In conclusion, these recommendations will serve as a brachytherapy protocol to be used at institutions with limited availability of MRI for 3D treatment planning.


Journal of Radiation Research | 2015

Difference in distant failure site between locally advanced squamous cell carcinoma and adenocarcinoma of the uterine cervix after C-ion RT.

Masaru Wakatsuki; Shingo Kato; Tatsuya Ohno; Hiroki Kiyohara; Kumiko Karasawa; Tomoaki Tamaki; Ken Ando; Daisuke Irie; Shintaro Shiba; Hirohiko Tsujii; Takashi Nakano; Tadashi Kamada; Makio Shozu

We investigated the first site of distant failure after carbon ion radiotherapy (C-ion RT) for locally advanced cervical cancer in three clinical trials. A total of 91 cases were enrolled in the three trials (Protocol 9702, 9704 and 9902). Histologically, 36 cases had squamous cell carcinoma (SqCC) and 55 cases had adenocarcinoma (AC), including 13 with adenosquamous cell carcinoma. The number of cases with Stage IIB, IIIB and IVA disease was 21, 59 and 11, respectively. Of the 91 cases, 42 had positive pelvic lymph nodes (PLNs). The median tumor size was 6.0 cm (range, 3.0–12.0 cm). The median follow-up duration for all cases was 40 months (range, 7–181 months). A total of 40 cases developed distant failure as the first site of failure: 13 of 36 (36.1%) SqCC cases had distant failure, with 9 of them with para-aortic lymph node (PALN) failure; 27 of 55 (44.0%) AC cases had distant failure, and 23 of them had distant failure excluding PALN metastasis. Distant failure rates of SqCC cases who had positive and negative PLNs before C-ion RT were 61.1% and 11.1%, respectively (P = 0.0045). Those of AC cases were 54.2% and 45.2%, respectively (P = 0.507). In conclusion, there were high rates of distant failure after C-ion RT in AC cases regardless of PLN status, and there were high rates of distant failure after C-ion RT, especially PALN failure, in SqCC cases with positive PLNs.


Journal of Radiation Research | 2017

Five-year quality of life assessment after carbon ion radiotherapy for prostate cancer.

Katsuya Maruyama; Hiroshi Tsuji; Takuma Nomiya; Hiroyuki Katoh; Hitoshi Ishikawa; Tadashi Kamada; Masaru Wakatsuki; Koichiro Akakura; Jun Shimazaki; Hirohiko Tsujii

Abstract The aim of this study was to prospectively assess 5-year health-related quality of life (HRQOL) of patients treated with carbon ion radiotherapy (C-ion RT) for clinically localized prostate cancer. A total of 417 patients received carbon ion radiotherapy at a total dose of 63–66 Gray-equivalents (GyE) in 20 fractions over 5 weeks, and neoadjuvant and adjuvant androgen deprivation therapy (ADT) were administered for intermediate and high-risk patients. A HRQOL assessment was performed at five time points (immediately before the initiation of C-ion RT, immediately after, and at 12, 36 and 60 months after completion of C-ion RT) using Functional Assessment of Cancer Therapy (FACT) questionnaires. FACT-G and FACT-P scores were significantly decreased; however, the absolute change after 60 months was minimal. The transient decreases in the Trial Outcome Index (TOI) score returned to their baseline levels. Use of ADT, presence of adverse events, and biochemical failure were related to lower scores. Scores of subdomains of FACT instruments indicated characteristic changes. The pattern of HRQOL change after C-ion RT was similar to that of other modalities. Further controlled studies focusing on a HRQOL in patients with prostate cancer are warranted.


Journal of Radiation Research | 2016

Carbon-ion radiotherapy for locally advanced cervical cancer with bladder invasion

Shintaro Shiba; Masaru Wakatsuki; Shingo Kato; Tatsuya Ohno; Noriyuki Okonogi; Kumiko Karasawa; Hiroki Kiyohara; Hirohiko Tsujii; Takashi Nakano; Tadashi Kamada; Makio Shozu

The purpose of this study was to evaluate the efficacy and toxicities of carbon-ion radiotherapy (C-ion RT) for locally advanced cervical cancer with bladder invasion by a subset analysis of pooled data from eight prospective clinical trials at the National Institute of Radiological Sciences. Between June 1995 and January 2014, 29 patients with locally advanced cervical cancer with bladder invasion were identified. The median age was 56 years old (range 31–79 years old). The median tumor size at diagnosis on magnetic resonance imaging was 6.7 cm (range 3.5–11.0 cm). Histologically, 20 patients had squamous cell carcinoma and 9 had adenocarcinoma. C-ion RT was performed as a dose-escalation study in the initial trials. All patients received prophylactic whole-pelvic or extended-field irradiation and local boost. The total dose to the cervical tumor was 52.8–74.4 Gy (relative biological effectiveness) in 20 or 24 fractions. Weekly cisplatin (40 mg/m2/week, five cycles) was concurrently given to four patients. The median follow-up of all patients was 28.6 months (range 8.8–238.6 months). Grade 2 or higher late complications in the bladder were observed in eight patients, with seven developing vesicovaginal fistula. Six patients had Grade 2 or higher complications in the rectosigmoid colon. The 3-year overall survival rate was 47%, the 3-year local control rate was 66%, and the 3-year disease-free survival rate was 28%. In this study, C-ion RT showed favorable local control with reasonable toxicities, but the results were still unsatisfactory. We have the expectation of improvement of therapeutic effects by using C-ion RT with concurrent chemotherapy.


Cancer Medicine | 2018

Clinical outcomes of carbon ion radiotherapy with concurrent chemotherapy for locally advanced uterine cervical adenocarcinoma in a phase 1/2 clinical trial (Protocol 1001)

Noriyuki Okonogi; Masaru Wakatsuki; Shingo Kato; Kumiko Karasawa; Hiroki Kiyohara; Shintaro Shiba; Daijiro Kobayashi; Takashi Nakano; Tadashi Kamada; Makio Shozu

We conducted a phase 1/2 study to evaluate the efficacy and safety of carbon ion radiotherapy (C‐ion RT) with concurrent chemotherapy for locally advanced uterine cervical adenocarcinoma. Thirty‐three patients were enrolled between April 2010 and March 2014. Treatment consisted of C‐ion RT with concurrent weekly cisplatin at a dose of 40 mg/m2. In the phase 1 component, the total dose was escalated from 68.0 Gy (relative biological effectiveness [RBE]) to 74.4 Gy (RBE) to determine the maximum tolerated dose of C‐ion RT. In the phase 2 component, the efficacy and safety of C‐ion RT with concurrent chemotherapy were evaluated using the dose determined in the phase 1 component. The median follow‐up duration was 30 months. Two patients did not receive chemotherapy because of anemia or leukocytopenia immediately prior to commencing treatment; 31 patients were analyzed. None of the patients developed dose‐limiting toxicities. The recommended dose (RD) was determined to be 74.4 Gy (RBE). In the phase 2 component, two patients developed Grade 3–4 toxicities in the gastrointestinal tract, due to repeated laser coagulation or peritonitis caused by appendicitis. In the patients treated with the RD, the 2‐year local control, progression‐free survival, and overall survival rates were 71%, 56%, and 88%, respectively. C‐ion RT with concurrent weekly cisplatin was well tolerated in patients with locally advanced uterine cervical adenocarcinoma. Our findings support further investigations into the efficacy of this strategy.


Journal of Radiation Research | 2017

Intravenous dendritic cell administration enhances suppression of lung metastasis induced by carbon-ion irradiation

Ken Ando; Hidetoshi Fujita; Akihiro Hosoi; Liqiu Ma; Masaru Wakatsuki; Ken-ichiro Seino; Kazuhiro Kakimi; Takashi Imai; Takashi Shimokawa; Takashi Nakano

Abstract Carbon-ion radiotherapy (CIRT) is an advanced radiotherapy and has achieved good local control, even in tumors that are resistant to conventional photon beam radiotherapy (PBRT). However, distant metastasis control is an important issue. Recently, the combination of radiotherapy and immunotherapy has attracted the attention. In immunotherapy, dendritic cells (DCs) play a pivotal role in the anti-tumor immune system. However, the mechanisms underlying the combination therapy of DCs and radiotherapy have been unclear. In the present study, we evaluated anti-metastatic effects of this combination therapy, focused on the irradiation type and the route of DC administration, using a mouse model. C3H/He mice bearing NR-S1 cells were treated with CIRT or PBRT, using biologically equivalent doses. Subsequently, DCs were administered intratumorally (IT) or intravenously (IV). IV and IT DC administrations combined with CIRT to the local tumor, but not alone, significantly suppressed pulmonary metastasis, whereas the combination of DCs with PBRT suppressed metastasis at a relatively higher dose. Additionally, the anti-metastatic effect was greater in IV DC administration compared with in IT DC administration in both CIRT and PBRT. The expression levels of CD40 and IL-12 in DCs were significantly increased after co-culturing with CIRT-treated NR-S1 cells. In addition, IV administration of those co-cultured DCs significantly suppressed pulmonary metastasis. Furthermore, ecto-calreticulin levels from CIRT-treated NR-S1 cells significantly increased compared with those of a PBRT-treated tumor. Taken together, these results suggest that local CIRT combined with IV DCs augments an immunogenicity of the tumor cells by ecto-calreticulin expression and the maturation of DCs to stimulate anti-tumor immunity to decrease lung metastases.


Journal of Radiation Research | 2013

Interfractional change of high-risk CTV D90 during image-guided brachytherapy for uterine cervical cancer

Yu Ohkubo; Tatsuya Ohno; Shin-ei Noda; Nobuteru Kubo; Akiko Nakagawa; Masahiro Kawahara; Takanori Abe; Hiroki Kiyohara; Masaru Wakatsuki; Takashi Nakano

The purpose of this study was to evaluate interfractional changes of the minimum dose delivered to 90% of the high-risk clinical target volume (HR-CTV D90) and D2cc of the bladder and rectum during brachytherapy for uterine cervical cancer patients. A total of 52 patients received external beam radiotherapy and high-dose-rate intracavitary brachytherapy (ICBT). For each of four ICBT applications, a pelvic CT scan was performed and the HR-CTV was delineated. Retrospectively, these patients were divided into two groups: (i) the standard dose group with 6 Gy to point A in each ICBT, and (ii) the adaptive dose group with a modified dose to point A to cover the HR-CTV with the 6-Gy isodose line as much as possible. The HR-CTV D90 was assessed in every session, and analyzed as interfractional changes. In the standard dose group, the interfractional changes of the HR-CTV D90 showed a linear increase from the first to the third of the four ICBT (average 6.1, 6.6, 7.0 and 7.1 Gy, respectively). In contrast, those of the adaptive dose group remained almost constant (average 7.2, 7.2, 7.3 and 7.4 Gy, respectively). Especially, in the case of a large HR-CTV volume (≥35 cm3) at first ICBT, the total HR-CTV D90 of the adaptive dose group with brachytherapy was significantly higher than that of the standard dose group. There were no significant differences in total D2cc in bladder and rectum between the two groups. Image-guided adaptive brachytherapy based on interfractional tumor volume change improves the dose to the HR-CTV while keeping rectal and bladder doses within acceptable levels.


Gynecologic Oncology | 2016

Phase II study of concurrent chemoradiotherapy with weekly cisplatin and paclitaxel in patients with locally advanced uterine cervical cancer: The JACCRO GY-01 trial

Kenji Umayahara; Munetaka Takekuma; Yasuyuki Hirashima; Shin-ei Noda; Tatsuya Ohno; Etsuko Miyagi; Fumiki Hirahara; Eiji Hirata; Eiji Kondo; Tsutomu Tabata; Yutaka Nagai; Yoichi Aoki; Masaru Wakatsuki; Masahiro Takeuchi; Takafumi Toita; Nobuhiro Takeshima; Ken Takizawa

OBJECTIVE A multicenter phase II trial was conducted to assess the efficacy and toxicity of concurrent chemoradiotherapy (CCRT) with weekly cisplatin (CDDP) and paclitaxel (PTX) in patients with locally advanced uterine cervical cancer. METHODS Patients with FIGO stage III-IVA uterine cervical cancer without para-aortic lymphadenopathy were enrolled. Patients received definitive radiotherapy (RT) consisting of external beam whole-pelvic RT and high-dose-rate intracavitary brachytherapy. The cumulative linear quadratic equivalent dose was 62-65Gy prescribed at point A. weekly CDDP at 30mg/m(2) and PTX at 50mg/m(2) were administered concurrently with RT for ≥5 courses. RESULTS Sixty-eight of the 70 registered patients were eligible. The complete response rate was 76.5% (95% confidence interval [CI], 66.4-86.6%). With a median follow-up of 27months (range, 7.9-33.5), the 2-year cumulative progression-free survival and the 2-year cumulative overall survival rates were 83.8% (95% CI, 75.1-92.6%) and 92.7% (95% CI, 86.4-98.9%), respectively. The pelvic cumulative disease progression-free and the 2-year cumulative distant metastasis rates were 89.6% (95% CI, 82.3-96.9%) and 13.2% (95% CI, 5.2-21.3%), respectively. The 2-year cumulative late complication rates were 25% for all grades, 13.2% for grade 1, 5.9% for grade 2, 2.9% for grade 3, and 2.9% for grade 4. CONCLUSIONS For locally advanced cervical cancer, CCRT with weekly CDDP 30mg/m(2) and PTX at 50mg/m(2) demonstrated favorable antitumor activity, and was feasible and safe with respect to the protocol-specified serious adverse reactions and events. Evaluation of this regimen in phase III trials is warranted.

Collaboration


Dive into the Masaru Wakatsuki's collaboration.

Top Co-Authors

Avatar

Tadashi Kamada

National Institute of Radiological Sciences

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Kumiko Karasawa

National Institute of Radiological Sciences

View shared research outputs
Top Co-Authors

Avatar

Shingo Kato

National Institute of Radiological Sciences

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Shintaro Shiba

National Institute of Radiological Sciences

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Hirohiko Tsujii

National Institute of Radiological Sciences

View shared research outputs
Top Co-Authors

Avatar

Noriyuki Okonogi

National Institute of Radiological Sciences

View shared research outputs
Researchain Logo
Decentralizing Knowledge