Masashi Kitano
Kitasato University
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Featured researches published by Masashi Kitano.
BJUI | 2009
Takefumi Satoh; Hiromichi Ishiyama; Kazumasa Matsumoto; Hideyasu Tsumura; Masashi Kitano; Kazushige Hayakawa; Shin Ebara; Yasutomo Nasu; Hiromi Kumon; Susumu Kanazawa; Kenta Miki; Shin Egawa; Manabu Aoki; Kazuhito Toya; Atsushi Yorozu; Hirohiko Nagata; Shiro Saito; Shiro Baba
To examine the incidence, timing, and magnitude of the prostate‐specific antigen (PSA) level ‘bounce’ after permanent prostate brachytherapy (BT) and correlate the PSA bounce with clinical and dosimetric factors in Japanese patients with prostate cancer.
Oncology | 2007
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.
International Journal of Radiation Oncology Biology Physics | 2009
Hiromichi Ishiyama; Masashi Kitano; Takefumi Satoh; Shouko Kotani; Mineko Uemae; Kazumasa Matsumoto; Hiroshi Okusa; Ken-ichi Tabata; Shiro Baba; Kazushige Hayakawa
PURPOSE To evaluate the severity of genitourinary (GU) toxicity in high-dose-rate (HDR) brachytherapy combined with hypofractionated external beam radiotherapy (EBRT) for prostate cancer and to explore factors that might affect the severity of GU toxicity. METHODS AND MATERIALS A total of 100 Japanese men with prostate cancer underwent (192)Ir HDR brachytherapy combined with hypofractionated EBRT. Mean (SD) dose to 90% of the planning target volume was 6.3 (0.7) Gy per fraction of HDR. After 5 fractions of HDR treatment, EBRT with 10 fractions of 3 Gy was administrated. The urethral volume receiving 1-15 Gy per fraction in HDR brachytherapy (V1-V15) and the dose to at least 5-100% of urethral volume in HDR brachytherapy (D5-D100) were compared between patients with Grade 3 toxicity and those with Grade 0-2 toxicity. Prostate volume, patient age, and International Prostate Symptom Score were also compared between the two groups. RESULTS Of the 100 patients, 6 displayed Grade 3 acute GU toxicity, and 12 displayed Grade 3 late GU toxicity. Regarding acute GU toxicity, values of V1, V2, V3, and V4 were significantly higher in patients with Grade 3 toxicity than in those with Grade 0-2 toxicity. Regarding late GU toxicity, values of D70, D80, V12, and V13 were significantly higher in patients with Grade 3 toxicity than in those with Grade 0-2 toxicity. CONCLUSIONS The severity of GU toxicity in HDR brachytherapy combined with hypofractionated EBRT for prostate cancer was relatively high. The volume of prostatic urethra was associated with grade of acute GU toxicity, and urethral dose was associated with grade of late GU toxicity.
International Journal of Radiation Oncology Biology Physics | 2011
Hideyasu Tsumura; Takefumi Satoh; Hiromichi Ishiyama; Ken-ichi Tabata; Shouko Kotani; Satoru Minamida; Masaki Kimura; Tetsuo Fujita; Kazumasa Matsumoto; Masashi Kitano; Kazushige Hayakawa; Shiro Baba
PURPOSE To compare the efficacy of three α(1A)/α(1D)-adrenoceptor (AR) antagonists--naftopidil, tamsulosin, and silodosin--that have differing affinities for the α(1)-AR subtypes in treating urinary morbidities in Japanese men with (125)I prostate implantation (PI) for prostate cancer. METHODS AND MATERIALS This single-institution prospective randomized controlled trial compared naftopidil, tamsulosin, and silodosin in patients undergoing PI. Patients were randomized and received either naftopidil, tamsulosin, or silodosin. Treatment began 1 day after PI and continued for 1 year. The primary efficacy variables were the changes in total International Prostate Symptom Score (IPSS) and postvoid residual urine (PVR). The secondary efficacy variables were changes in IPSS storage score and IPSS voiding score from baseline to set points during the study (1, 3, 6, and 12 months). RESULTS Two hundred twelve patients were evaluated in this study between June 2006 and February 2009: 71, 70, and 71 patients in the naftopidil, tamsulosin, and silodosin groups, respectively. With respect to the primary efficacy variables, the mean changes in the total IPSS at 1 month after PI in the naftopidil, tamsulosin, and silodosin groups were +10.3, +8.9, and +7.5, respectively. There were significantly greater decreases with silodosin than naftopidil at 1 month in the total IPSS. The mean changes in the PVR at 6 months were +14.6, +23.7, and +5.7 mL in the naftopidil, tamsulosin, and silodosin groups, respectively; silodosin showed a significant improvement in the PVR at 6 months vs. tamsulosin. With respect to the secondary efficacy variables, the mean changes in the IPSS voiding score at 1 month in the naftopidil, tamsulosin, and silodosin groups were +6.5, +5.6, and +4.5, respectively; silodosin showed a significant improvement in the IPSS voiding score at 1 month vs. naftopidil. CONCLUSIONS Silodosin has a greater impact on improving PI-induced lower urinary tract symptoms than the other two agents.
Japanese Journal of Clinical Oncology | 2008
Hiromichi Ishiyama; Takefumi Satoh; Masashi Kitano; Hideyasu Tsumura; Shouko Kotani; Hiroshi Okusa; Mineko Uemae; Shiro Baba; Kazushige Hayakawa
OBJECTIVE To report 4 year results obtained with our initial 100 patients with localized prostate cancer treated by interstitial permanent brachytherapy. METHODS One-hundred Japanese men with clinically localized prostate cancer underwent interstitial permanent prostate brachytherapy using (125)I seeds. Median follow-up was 36 months (range, 30-42 months). Median initial prostate-specific antigen (PSA) level was 6.7 ng/ml (range, 1.5-25.2 ng/ml). Of these 100 patients, 31 received neoadjuvant hormone therapy for several months. Treatment morbidities were assessed using Radiation Therapy Oncology Group (RTOG) scale and National Cancer Institute Common Toxicity Criteria. RESULTS A mean of 95 seeds (range, 48-123 seeds) were successfully implanted in patients with prostate cancer. Mean prostate volume receiving at least 100% dose (V100) and dose to 90% of prostate volume (D90) for the 100 patients were 96.6% and 166.1 Gy, respectively. Urinary morbidity was common, but was usually not severe. Only four patients needed catheterization for urinary retention (Grade 3) during follow-up. Most patients displayed no rectal morbidity after implantation, with only 3% of patients showing RTOG Grade 2 rectal morbidity and no patients showing morbidity of Grade 3 or more. Three patients experienced biochemical failure according to Phoenix consensus definition during follow-up. One patient displayed clinical failure with lymph node recurrence. CONCLUSIONS These results indicate that interstitial permanent brachytherapy is safe and effective for Japanese patients with localized prostate cancer. The import of matured techniques developed in Western countries might allow bypass of the trial-and-error process in Japanese institutions.
Journal of Contemporary Brachytherapy | 2014
Shogo Kawakami; Hiromichi Ishiyama; Tsuyoshi Terazaki; Itaru Soda; Takefumi Satoh; Masashi Kitano; Shinji Kurosaka; Akane Sekiguchi; Shouko Komori; Masatsugu Iwamura; Kazushige Hayakawa
Purpose The purpose of this work was to report measured catheter displacement prior to the delivery of high-dose-rate brachytherapy (HDR) in the treatment of prostate cancer. Material and methods Data from 30 prostate cancer patients treated with HDR brachytherapy were analyzed retrospectively. Eighteen transperineal hollow catheters were inserted under transrectal ultrasound guidance. Gold marker seeds were also placed transperineally into the base and apex of the prostate gland. Five treatment fractions of 7.5 Gy each were administered over 3 days. The patient underwent CT scanning prior to each treatment fraction. Catheter displacement was measured from the pre-treatment CT dataset reconstructed at 1.25 mm slice thickness. Results Most of catheters were displaced in the caudal direction. Variations of 18 catheters for each patient were small (standard deviations < 1 mm for all but one patient). Mean displacements relative to the apex marker were 6 ± 4 mm, 12 ± 6 mm, 12 ± 6 mm, 12 ± 6 mm, and 12 ± 6 mm from plan to 1st, 2nd, 3rd, 4th, and 5th fractions, respectively. Conclusions Our results indicate that catheter positions must be confirmed and if required, adjusted, prior to every treatment fraction for the precise treatment delivery of HDR brachytherapy, and to potentially reduce over-dosage to the bulbo-membranous urethra.
Journal of Radiation Research | 2014
Hiromichi Ishiyama; Takefumi Satoh; Masashi Kitano; Ken-ichi Tabata; Shouko Komori; Masaomi Ikeda; Itaru Soda; Shinji Kurosaka; Akane Sekiguchi; Masaki Kimura; Shogo Kawakami; Masatsugu Iwamura; Kazushige Hayakawa
The purpose of this study was to report the outcomes of high-dose-rate (HDR) brachytherapy and hypofractionated external beam radiotherapy (EBRT) combined with long-term androgen deprivation therapy (ADT) for National Comprehensive Cancer Network (NCCN) criteria-defined high-risk (HR) and very high-risk (VHR) prostate cancer. Data from 178 HR (n = 96, 54%) and VHR (n = 82, 46%) prostate cancer patients who underwent 192Ir-HDR brachytherapy and hypofractionated EBRT with long-term ADT between 2003 and 2008 were retrospectively analyzed. The mean dose to 90% of the planning target volume was 6.3 Gy/fraction of HDR brachytherapy. After five fractions of HDR treatment, EBRT with 10 fractions of 3 Gy was administered. All patients initially underwent ≥6 months of neoadjuvant ADT, and adjuvant ADT was continued for 36 months after EBRT. The median follow-up was 61 months (range, 25–94 months) from the start of radiotherapy. The 5-year biochemical non-evidence of disease, freedom from clinical failure and overall survival rates were 90.6% (HR, 97.8%; VHR, 81.9%), 95.2% (HR, 97.7%; VHR, 92.1%), and 96.9% (HR, 100%; VHR, 93.3%), respectively. The highest Radiation Therapy Oncology Group-defined late genitourinary toxicities were Grade 2 in 7.3% of patients and Grade 3 in 9.6%. The highest late gastrointestinal toxicities were Grade 2 in 2.8% of patients and Grade 3 in 0%. Although the 5-year outcome of this tri-modality approach seems favorable, further follow-up is necessary to validate clinical and survival advantages of this intensive approach compared with the standard EBRT approach.
World Journal of Radiology | 2015
Hideyasu Tsumura; T. Satoh; Hiromichi Ishiyama; Shuhei Hirano; Ken-ichi Tabata; Shinji Kurosaka; Kazumasa Matsumoto; Tetsuo Fujita; Masashi Kitano; Shiro Baba; Kazushige Hayakawa; Masatsugu Iwamura
AIM To investigate the time course of testosterone (T) recovery after cessation of androgen deprivation therapy (ADT) in patients treated with brachytherapy. METHODS One-hundred and seventy-four patients treated between June 1999 and February 2009 were studied. Patients were divided into a short-term usage group (≤ 12 mo, n = 91) and a long-term usage group (≥ 36 mo, n = 83) according to the duration of gonadotropin-releasing hormone agonist therapy. Median follow-up was 29 mo in the short-term group and was 60 mo in the long-term group. RESULTS Cumulative incidence rates of T recovery to normal and supracastrate levels at 24 mo after cessation were 28.8% and 74.6%, respectively, in the long-term usage group, whereas these values were 96.4% and 98.8% in the short-term usage group. T recovery to normal and supracastrate levels occurred significantly more rapidly in the short-term than in the long-term usage group (P < 0.001 and P < 0.001, respectively). Five years after cessation, 22.6% of patients maintained a castrate T level in the long-term usage group. On multivariate analysis, lower T levels (< 10 ng/dL) at cessation of ADT was significantly associated with prolonged T recovery to supracastrate levels in the long-term usage group (P = 0.002). CONCLUSION Lower T levels at cessation of ADT were associated with prolonged T recovery in the long-term usage group. Five years after cessation of long-term ADT, approximately one-fifth of patients still had castrate T levels. When determining the therapeutic effect, especially biochemical control, we should consider this delay in T recovery.
International Journal of Molecular Sciences | 2017
Hideyasu Tsumura; T. Satoh; Hiromichi Ishiyama; Ken-ichi Tabata; Kouji Takenaka; Akane Sekiguchi; Masaki Nakamura; Masashi Kitano; Kazushige Hayakawa; Masatsugu Iwamura
Despite the absence of local prostate cancer recurrence, some patients develop distant metastases after prostate brachytherapy. We evaluate whether prostate brachytherapy procedures have a potential risk for hematogenous spillage of prostate cancer cells. Fifty-nine patients who were undergoing high-dose-rate (HDR) or low-dose-rate (LDR) brachytherapy participated in this prospective study. Thirty patients with high-risk or locally advanced cancer were treated with HDR brachytherapy after neoadjuvant androgen deprivation therapy (ADT). Twenty-nine patients with clinically localized cancer were treated with LDR brachytherapy without neoadjuvant ADT. Samples of peripheral blood were drawn in the operating room before insertion of needles (preoperative) and again immediately after the surgical manipulation (intraoperative). Blood samples of 7.5 mL were analyzed for circulating tumor cells (CTCs) using the CellSearch System. While no preoperative samples showed CTCs (0%), they were detected in intraoperative samples in 7 of the 59 patients (11.8%; preoperative vs. intraoperative, p = 0.012). Positive CTC status did not correlate with perioperative variables, including prostate-specific antigen (PSA) at diagnosis, use of neoadjuvant ADT, type of brachytherapy, Gleason score, and biopsy positive core rate. We detected CTCs from samples immediately after the surgical manipulation. Further study is needed to evaluate whether those CTCs actually can survive and proliferate at distant sites.
Journal of Contemporary Brachytherapy | 2016
Hideyasu Tsumura; T. Satoh; Hiromichi Ishiyama; Ken-ichi Tabata; Shouko Komori; Akane Sekiguchi; Masaomi Ikeda; Shinji Kurosaka; Tetsuo Fujita; Masashi Kitano; Kazushige Hayakawa; Masatsugu Iwamura
Purpose To evaluate the prognostic value of prostate-specific antigen nadir (nPSA) after high-dose-rate (HDR) brachytherapy in clinically non-metastatic high-risk prostate cancer patients. Material and methods Data from 216 patients with high-risk or locally advanced prostate cancer who underwent HDR brachytherapy and external beam radiation therapy with long-term androgen deprivation therapy (ADT) between 2003 and 2008 were analyzed. The median prostate-specific antigen (PSA) level at diagnosis was 24 ng/ml (range: 3-338 ng/ml). The clinical stage was T1c-2a in 55 cases (26%), T2b-2c in 48 (22%), T3a in 75 (35%), and T3b-4 in 38 (17%). The mean dose to 90% of the planning target volume was 6.3 Gy/fraction of HDR brachytherapy. After 5 fractions, external beam radiation therapy with 10 fractions of 3 Gy was administered. All patients initially underwent neoadjuvant ADT for at least 6 months, and adjuvant ADT was continued for 36 months. The median follow-up was 7 years from the start of radiotherapy. Results The 7-year PSA relapse-free rate among patients with a post-radiotherapy nPSA level of ≤ 0.02 ng/ml was 94%, compared with 23% for patients with higher nPSA values (HR = 28.57; 95% CI: 12.04-66.66; p < 0.001). Multivariate analysis revealed that the nPSA value after radiotherapy was a significant independent predictor of biochemical failure, whereas pretreatment predictive values for worse biochemical control including higher level of initial PSA, Gleason score ≥ 8, positive biopsy core rate ≥ 67%, and T3b-T4, failed to reach independent predictor status. The 7-year cancer-specific survival rate among patients with a post-radiotherapy nPSA level of ≤ 0.02 ng/ml was 99%, compared with 82% for patients with higher nPSA values (HR = 32.25; 95% CI: 3.401-333.3; p = 0.002). Conclusions A post-radiotherapy nPSA value of ≤ 0.02 ng/ml was associated with better long-term biochemical tumor control even if patients had pretreatment predictive values for worse control.