Details of a Researcher - Shiraishi, Yutaka

Papers - Shiraishi, Yutaka

Division display 21 - 33 of about 33 ／ All the affair displays >>

Outcomes following iodine-125 prostate brachytherapy with or without neoadjuvant androgen deprivation

Ohashi Toshio, Yorozu Atsunori, Saito Shiro, Momma Tetsuo, Toya Kazuhito, Nishiyama Toru, Yamashita Shoji, Shiraishi Yutaka, Shigematsu Naoyuki

Radiotherapy and Oncology (Radiotherapy and Oncology) 109 ( 2 ) 241 - 245 2013.11

ISSN 0167-8140

Purpose To report the biochemical failure-free survival (BFFS), cause-specific survival (CSS), and overall survival (OS) outcomes of patients treated with iodine-125 (I-125) brachytherapy for clinically localized prostate cancer. Methods and materials Between 2003 and 2009, I-125 permanent prostate brachytherapy without supplemental external-beam radiotherapy was performed for 663 patients with low-risk and low-tier intermediate-risk (defined as organ-confined disease, PSA <10 ng/mL, and Gleason score 3 + 4 with biopsy positive core rate <33%) prostate cancer. Early in the study period, the preplanning method was used in the first 104 patients, and later the real-time planning method was used. Biochemical failure was determined using the American Society for Therapeutic Radiology Oncology (ASTRO) and Phoenix definitions. Results The 7-year BFFS rates for the ASTRO and Phoenix definitions were 96.1% and 95.9%, respectively. The corresponding BFFS rates by risk group were 97.6% and 96.7% for low-risk, and 91.8% and 93.6% for low-tier intermediate-risk disease (p = 0.007 and 0.08, respectively). The median times to biochemical failure in those who failed were 29.5 and 43.9 months according to the ASTRO and Phoenix definitions, respectively. The 7-year CSS and OS were 99.1% and 96.4%. There was no significant difference in CSS or OS between the low-risk and low-tier intermediate-risk groups. In multivariate Cox regression analysis, risk group and prostate D90 were independent predictors of BFFS for the ASTRO definition, while only the prostate D90 was significant for the Phoenix definition. Conclusion I-125 prostate brachytherapy results in excellent 7-year BFFS, CSS, and OS for low-risk and low-tier intermediate-risk prostate cancer. © 2013 Elsevier Ireland Ltd. All rights reserved.

Access to Document (DOI)

Novel parameter predicting grade 2 rectal bleeding after iodine-125 prostate brachytherapy combined with external beam radiation therapy

Shiraishi Yutaka, Hanada Takashi, Ohashi Toshio, Yorozu Atsunori, Toya Kazuhito, Saito Shiro, Shigematsu Naoyuki

International Journal of Radiation Oncology Biology Physics (International Journal of Radiation Oncology Biology Physics) 87 ( 1 ) 182 - 187 2013.09

ISSN 0360-3016

Purpose: To propose a novel parameter predicting rectal bleeding on the basis of generalized equivalent uniform doses (gEUD) after ¹²⁵I prostate brachytherapy combined with external beam radiation therapy and to assess the predictive value of this parameter. Methods and Materials: To account for differences among radiation treatment modalities and fractionation schedules, rectal dose-volume histograms (DVHs) of 369 patients with localized prostate cancer undergoing combined therapy retrieved from corresponding treatment planning systems were converted to equivalent dose-based DVHs. The gEUDs for the rectum were calculated from these converted DVHs. The total gEUD (gEUD_sum) was determined by a summation of the brachytherapy and external-beam radiation therapy components. Results: Thirty-eight patients (10.3%) developed grade 2+ rectal bleeding. The grade 2+ rectal bleeding rate increased as the gEUD_sum increased: 2.0% (2 of 102 patients) for <70 Gy, 10.3% (15 of 145 patients) for 70-80 Gy, 15.8% (12 of 76 patients) for 80-90 Gy, and 19.6% (9 of 46 patients) for >90 Gy (P=.002). Multivariate analysis identified age (P=.024) and gEUD_sum (P=.000) as risk factors for grade 2+ rectal bleeding. Conclusions: Our results demonstrate gEUD to be a potential predictive factor for grade 2+ late rectal bleeding after combined therapy for prostate cancer. © 2013 Elsevier Inc.

Access to Document (DOI)

Comparison of preplanning and intraoperative planning for I-125 prostate brachytherapy

Yoshida Kayo, Ohashi Toshio, Yorozu Atsunori, Toya Kazuhito, Nishiyama Toru, Saito Shiro, Hanada Takashi, Shiraishi Yutaka, Shigematsu Naoyuki

Japanese Journal of Clinical Oncology (Japanese Journal of Clinical Oncology) 43 ( 4 ) 383 - 389 2013.04

ISSN 0368-2811

Objective: To compare two widely used permanent prostate brachytherapy techniques, preplanning and intraoperative planning, based on postimplant dosimetry, toxicity and biochemical outcomes. Methods: Between 2003 and 2006, 665 men with localized prostate cancer were treated with permanent interstitial implantation. The first 227 consecutive men were treated with the preplanning technique, followed by 438 men treated with the intraoperative technique. Late toxicity was scored by the Common Terminology Criteria for Adverse Events v.4.0. Biochemical failure was defined as a prostate-specific antigen increase of more than 2 ng/ml above the nadir value excluding a benign bounce. Univariate and multivariate analyses were performed to identify the variables associated with biochemical failure-free survival. Results: Postimplant target coverage was similar in the two groups, with a small difference in risk organ doses. Mean V100 was 96.3 vs. 96.7% (P = 0.205), D90 was 119.6 vs. 119.4% (P = 0.884), urethral D10 was 157.5 vs. 146.1% (P = 0.010), rectal V100 was 0.57 vs. 0.43 cc (P = 0.002) in the preplanning and intraoperative planning groups, respectively. Acute and late Grade 3 genitourinary and gastrointestinal toxicities were , <1% for both methods. The 5-year biochemical failure-free survival rate was 95.4% for the preplanning and 94.0% for the intraoperative planning group (P = 0.776). Multivariate analysis revealed Gleason score, biopsy positive rate and V100 to be predictors of biochemical failure-free survival, while the planning technique was not significant. Conclusion: This large-scale analysis of high-quality implants revealed similar postimplant dosimetry, toxicity profiles and biochemical failure-free survival for the preplanning and intraoperative planning methods. © The Author 2013. Published by Oxford University Press. All rights reserved.

Access to Document (DOI)

Detection of esophageal fiducial marker displacement during radiation therapy with a 2-dimensional on-board imager

Fukada Junichi, Hanada Takashi, Kawaguchi Osamu, Ohashi Toshio, Takeuchi Hiroya, Kitagawa Yuko, Seki Satoshi, Shiraishi Yutaka, Ogata Haruhiko, Shigematsu Naoyuki

International Journal of Radiation Oncology Biology Physics (International Journal of Radiation Oncology Biology Physics) 85 ( 4 ) 991 - 998 2013.03

ISSN 0360-3016

Purpose: To quantify the interfraction displacement of esophageal fiducial markers for primary esophageal cancer radiation therapy. Methods and Materials: Orthogonal 2-dimensional (2D) matching records fused to vertebrae were analyzed in clinically staged T1/2N0 esophageal cancer patients undergoing endoscopic clipping as fiducial metal markers. Displacement of the markers between the digitally reconstructed radiographs and on-board kilovoltage images during radiation therapy was analyzed according to direction and esophageal site. Results: Forty-four patients, with 81 markers (10 proximal, 42 middle, and 29 distal), underwent 367 2D matching sessions during radiation therapy. The mean (SD) absolute marker displacement was 0.26 (0.30) cm in the right-left (RL), 0.50 (0.39) cm in the superior-inferior (SI), and 0.24 (0.21) cm in the anterior-posterior (AP) direction. Displacement was significantly larger in the SI than in the RL and AP directions (P<.0001). In the SI direction, mean absolute displacements of the distal, middle, and proximal esophagus were 0.67 (0.45) cm, 0.42 (0.32) cm, and 0.36 (0.30) cm, respectively. Distal esophagus displacement was significantly larger than those of the middle and proximal esophagus (P<.0001). The estimated internal margin to cover 95% of the cases was 0.75 cm in the RL and AP directions. In the SI direction, the margin was 1.25 cm for the proximal and middle esophagus and 1.75 cm for the distal esophagus. Conclusions: The magnitude of interfraction displacement of esophageal clips was larger in the SI direction, particularly in the distal esophagus, but substantial displacement was observed in other directions and at other esophageal sites. It is practical to take estimated movements into account with internal margins, even if vertebrae-based 2D matching is performed. © 2013 Elsevier Inc. All rights reserved.

Access to Document (DOI)

Prostate brachytherapy seed migration to a left varicocele

Sugawara Akitomo, Nakashima Jun, Kunieda Etsuo, Nagata Hirohiko, Mizuno Ryuichi, Seki Satoshi, Shiraishi Yutaka, Kouta Ryuichi, Oya Mototsugu, Shigematsu Naoyuki

Brachytherapy (Brachytherapy) 11 ( 6 ) 502 - 506 2012.11

ISSN 1538-4721

Purpose: To report a rare case of seed migration to a left varicocele after transperineal interstitial prostate brachytherapy with loose iodine-125 (¹²⁵I) seeds. Methods and Materials: A 73-year-old man presented with a serum prostate-specific antigen level of 5.21ng/mL, Gleason score of 7 (3+4), and clinical T1c adenocarcinoma of the prostate. The patient underwent transperineal interstitial prostate brachytherapy with loose ¹²⁵I seeds followed by external beam radiation therapy. Two weeks after seed implantation, a followup pelvic radiograph was obtained. One month after seed implantation, a pelvic computed tomography scan for postimplant dosimetric analysis was carried out. Subsequent ultrasound examination of the scrotum was undertaken. Results: Two weeks after seed implantation, an anteroposterior pelvic radiograph showed that a migrated seed was overlapped by the scrotum. Postimplant pelvic computed tomography revealed that a seed had migrated to the left side of the scrotum. Subsequent ultrasound examination of the scrotum revealed that the patient had a left varicocele to which the seed had migrated. The patient had no symptoms related to the migrated seed. Conclusions: This is the first report of seed migration to a left varicocele after transperineal interstitial prostate brachytherapy with loose ¹²⁵I seeds. For the present case, we suggest that the seed moved from the prostate to the left varicocele through the pelvic veins, bypassing the systemic circulation. © 2012 American Brachytherapy Society.

Access to Document (DOI)

Preimplant factors affecting prostate D90 after transperineal interstitial prostate brachytherapy with loose ¹²⁵I seeds

Sugawara Akitomo, Nakashima Jun, Kunieda Etsuo, Nagata Hirohiko, Mizuno Ryuichi, Takeda Atsuya, Seki Satoshi, Shiraishi Yutaka, Kouta Ryuichi, Oya Mototsugu, Shigematsu Naoyuki

Keio Journal of Medicine 61 ( 3 ) 89 - 94 2012.09

ISSN 0022-9717

The dose received by 90% of the prostate volume (D90) is the key parameter of dosimetric analysis in prostate brachytherapy. The aim of this analysis was to identify preimplant factors affecting prostate D90 after transperineal interstitial prostate brachytherapy with loose ¹²⁵I seeds. We reviewed the records of 210 patients who underwent transperineal interstitial prostate brachytherapy with loose ¹²⁵I seeds for clinical T1/T2 prostate cancer at our institution. Patients who received supplemental external-beam radiation therapy were excluded. One hundred and nine patients (51.9%) received neoadjuvant hormonal therapy (NHT). One month after seed implantation, postimplant computed tomography and dosimetric analysis were performed. Univariate and multivariate analyses were carried out to identify preimplant factors affecting postimplant prostate D90. The postimplant prostate D90 values ranged from 123.3 to 234.1 Gy (mean ± standard error, 177.1 ± 1.4 Gy). Postimplant prostate D90 differed significantly between patients who had and had not undergone NHT (P = 0.001). In addition, simple regression analyses showed positive correlations with the estimated preimplant prostate D90, preimplant prostate volume by transrectal ultrasound (TRUS), total radioactivity, number of needles, and number of seeds. On stepwise multiple regression analysis, postimplant prostate D90 showed significant negative correlations with NHT and preimplant prostate volume by TRUS, and a significant positive correlation with total radioactivity. In conclusion, NHT, preimplant prostate volume by TRUS, and total radioactivity are significant preimplant factors affecting postimplant prostate D90 in prostate cancer patients treated with transperineal interstitial prostate brachytherapy with loose ¹²⁵I seeds. © 2012 by The Keio Journal of Medicine.

Result of salvage radiotherapy for post-operative PSA failure of prostate cancer

Sakayori M., Ohashi T., Fukada J., Shiraishi Y., Hanada T., Shigematsu N.

Japanese Journal of Clinical Radiology 57 ( 9 ) 1193 - 1199 2012.09

ISSN 0009-9252

Fifty-five patients with PSA failure were treated with salvage radiotherapy. Post-operative and postradiotherapy PSA failure was defined as the PSA elevation (nadir+0.2ng/ml) or the initiation of hormone therapy. The median follow-up period after salvage radiotherapy was 32 months (range ; l-67months). The 3-yrs biochemical free survival and overall survival rate was 66.7% and 100%. Result of salvage radiotherapy for post-operation PSA failure is good and only the dose was significant predictive factor (60Gy vs > 64Gy ; 53.9% vs 862%).

Preimplant factors affecting prostate D90 after transperineal interstitial prostate brachytherapy with loose 125I seeds

Sugawara A., Nakashima J., Kunieda E., Nagata H., Mizuno R., Takeda A., Seki S., Shiraishi Y., Kouta R., Oya M., Shigematsu N.

Keio Journal of Medicine (Keio Journal of Medicine) 61 ( 3 ) 89 - 94 2012.09

ISSN 00229717

The dose received by 90% of the prostate volume (D90) is the key parameter of dosimetric analysis in prostate brachytherapy. The aim of this analysis was to identify preimplant factors affecting prostate D90 after transperineal interstitial prostate brachytherapy with loose 125I seeds. We reviewed the records of 210 patients who underwent transperineal interstitial prostate brachytherapy with loose 125I seeds for clinical T1/T2 prostate cancer at our institution. Patients who received supplemental external-beam radiation therapy were excluded. One hundred and nine patients (51.9%) received neoadjuvant hormonal therapy (NHT). One month after seed implantation, postimplant computed tomography and dosimetric analysis were performed. Univariate and multivariate analyses were carried out to identify preimplant factors affecting postimplant prostate D90. The postimplant prostate D90 values ranged from 123.3 to 234.1 Gy (mean ± standard error, 177.1 ± 1.4 Gy). Postimplant prostate D90 differed significantly between patients who had and had not undergone NHT (P = 0.001). In addition, simple regression analyses showed positive correlations with the estimated preimplant prostate D90, preimplant prostate volume by transrectal ultrasound (TRUS), total radioactivity, number of needles, and number of seeds. On stepwise multiple regression analysis, postimplant prostate D90 showed significant negative correlations with NHT and preimplant prostate volume by TRUS, and a significant positive correlation with total radioactivity. In conclusion, NHT, preimplant prostate volume by TRUS, and total radioactivity are significant preimplant factors affecting postimplant prostate D90 in prostate cancer patients treated with transperineal interstitial prostate brachytherapy with loose 125I seeds. © 2012 by The Keio Journal of Medicine.

Access to Document (DOI)

Result of salvage radiotherapy for post-operative PSA failure of prostate cancer: Evaluation of predictive factors

Sakayori M., Ohashi T., Fukada J., Shiraishi Y., Hanada T., Shigematsu N.

Japanese Journal of Clinical Radiology (Japanese Journal of Clinical Radiology) 57 ( 9 ) 1193 - 1199 2012.09

ISSN 00099252

Fifty-five patients with PSA failure were treated with salvage radiotherapy. Post-operative and postradiotherapy PSA failure was defined as the PSA elevation (nadir+0.2ng/ml) or the initiation of hormone therapy. The median follow-up period after salvage radiotherapy was 32 months (range ; l-67months). The 3-yrs biochemical free survival and overall survival rate was 66.7% and 100%. Result of salvage radiotherapy for post-operation PSA failure is good and only the dose was significant predictive factor (60Gy vs > 64Gy ; 53.9% vs 862%).

Pericardial and pleural effusions after definitive radiotherapy for esophageal cancer

Fukada Junichi, Shigematsu Naoyuki, Ohashi Toshio, Shiraishi Yutaka, Takeuchi Hiroya, Kawaguchi Osamu, Kitagawa Yuko

Journal of Radiation Research (Journal of Radiation Research) 53 ( 3 ) 447 - 453 2012.05

ISSN 0449-3060

Purpose: We investigated the incidences of pericardial and pleural effusions after definitive radiotherapy with or without concurrent chemotherapy were analyzed retrospectively. Methods: One hundred and forty-seven patients with esophageal cancer received definitive radiotherapy or concurrent chemoradiotherapy (CCR). Follow-up chest Computed Tomography scans were reviewed to detect pericardial and pleural effusions. Adverse events were graded according to the Radiation Therapy Oncology Group Common Toxicity Criteria. Results: The median follow-up was 34 (range, 6 to 84) months. Numbers of eligible patients evaluated for pericardial and pleural effusions were 107 and 101, respectively. Pericardial effusions exceeding grade 1 and grade 2 toxicities were observed in 46 (43%) and 15 (14%) patients, respectively. The corresponding numbers for pleura! effusions were 44 (44%) and 18 (18%). Onset of effusion ranged from 1 to 65 months after treatment. Multivariate analysis identified radiation field width of the mediastinum exceeding 8 cm as a significant risk factor for both pericardial and pleural effusions. Age and field length exceeding 20 cm were identified as independent risk factors for pleural effusion. Conclusions: Pericardial and pleural effusions after radiotherapy or CCR are occasionally recognized as adverse events in patients with esophageal cancer. The mediastinal radiation field width can be a simple indicator for predicting those adverse events.

Access to Document (DOI)

Clinical evidence of particle beam therapy

Shigematsu Naoyuki, Shiraishi Yutaka, Seki Satoshi, Fukada Junichi, Ohashi Toshio

International Journal of Clinical Oncology 17 ( 2 ) 75 - 78 2012.04

ISSN 1341-9625

Access to Document (DOI)

Dose constraint for minimizing grade 2 rectal bleeding following brachytherapy combined with external beam radiotherapy for localized prostate cancer

Shiraishi Yutaka, Yorozu Atsunori, Ohashi Toshio, Toya Kazuhito, Seki Satoshi, Yoshida Kayo, Kaneda Tomoya, Saito Shiro, Nishiyama Toru, Hanada Takashi, Shigematsu Naoyuki

International Journal of Radiation Oncology Biology Physics (International Journal of Radiation Oncology Biology Physics) 81 ( 3 ) 2011.11

ISSN 0360-3016

Purpose: To determine the rectal tolerance to Grade 2 rectal bleeding after I-125 seed brachytherapy combined with external beam radiotherapy (EBRT), based on the rectal dose-volume histogram. Methods and Materials: A total of 458 consecutive patients with stages T1 to T3 prostate cancer received combined modality treatment consisting of I-125 seed implantation followed by EBRT to the prostate and seminal vesicles. The prescribed doses of brachytherapy and EBRT were 100 Gy and 45 Gy in 25 fractions, respectively. The rectal dosimetric factors were analyzed for rectal volumes receiving >100 Gy and >150 Gy (R100 and R150) during brachytherapy and for rectal volumes receiving >30 Gy to 40 Gy (V30-V40) during EBRT therapy in 373 patients for whom datasets were available. The patients were followed from 21 to 72 months (median, 45 months) after the I-125 seed implantation. Results: Forty-four patients (9.7%) developed Grade 2 rectal bleeding. On multivariate analysis, age (p = 0.014), R100 (p = 0.002), and V30 (p = 0.001) were identified as risk factors for Grade 2 rectal bleeding. The rectal bleeding rate increased as the R100 increased: 5.0% (2/40 patients) for 0 ml; 7.5% (20/267 patients) for >0 to 0.5 ml; 11.0% (11/100 patients) for >0.5 to 1 ml; 17.9% (5/28 patients) for >1 to 1.5 ml; and 27.3% (6/22 patients) for >1.5 ml (p = 0.014). Grade 2 rectal bleeding developed in 6.4% (12/188) of patients with a V30 ≤35% and in 14.1% (26/185) of patients with a V30 >35% (p = 0.02). When these dose-volume parameters were considered in combination, the Grade 2 rectal bleeding rate was 4.2% (5/120 patients) for a R100 ≤0.5 ml and a V30 ≤35%, whereas it was 22.4% (13/58 patients) for R100 of >0.5 ml and V30 of >35%. Conclusion: The risk of rectal bleeding was found to be significantly volume-dependent in patients with prostate cancer who received combined modality treatment. Rectal dose-volume analysis is a practical method for predicting the risk of development of Grade 2 rectal bleeding. © 2011 Elsevier Inc.

Access to Document (DOI)

Incidence of seed migration to the chest, abdomen, and pelvis after transperineal interstitial prostate brachytherapy with loose ¹²⁵I seeds

Sugawara Akitomo, Nakashima Jun, Kunieda Etsuo, Nagata Hirohiko, Mizuno Ryuichi, Seki Satoshi, Shiraishi Yutaka, Kouta Ryuichi, Oya Mototsugu, Shigematsu Naoyuki

Radiation Oncology (Radiation Oncology) 6 ( 1 ) 2011.10

Background: The aim was to determine the incidence of seed migration not only to the chest, but also to the abdomen and pelvis after transperineal interstitial prostate brachytherapy with loose ¹²⁵I seeds.Methods: We reviewed the records of 267 patients who underwent prostate brachytherapy with loose ¹²⁵I seeds. After seed implantation, orthogonal chest radiographs, an abdominal radiograph, and a pelvic radiograph were undertaken routinely to document the occurrence and sites of seed migration. The incidence of seed migration to the chest, abdomen, and pelvis was calculated. All patients who had seed migration to the abdomen and pelvis subsequently underwent a computed tomography scan to identify the exact location of the migrated seeds. Postimplant dosimetric analysis was undertaken, and dosimetric results were compared between patients with and without seed migration.Results: A total of 19,236 seeds were implanted in 267 patients. Overall, 91 of 19,236 (0.47%) seeds migrated in 66 of 267 (24.7%) patients. Sixty-nine (0.36%) seeds migrated to the chest in 54 (20.2%) patients. Seven (0.036%) seeds migrated to the abdomen in six (2.2%) patients. Fifteen (0.078%) seeds migrated to the pelvis in 15 (5.6%) patients. Seed migration occurred predominantly within two weeks after seed implantation. None of the 66 patients had symptoms related to the migrated seeds. Postimplant prostate D90 was not significantly different between patients with and without seed migration.Conclusion: We showed the incidence of seed migration to the chest, abdomen and pelvis. Seed migration did not have a significant effect on postimplant prostate D90. © 2011 Sugawara et al; licensee BioMed Central Ltd.

Access to Document (DOI)

　 Previous page - Next page 　