Yasuyuki Hamada

Kumamoto Kinoh Hospital, Kumamoto, Kumamoto, Japan

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Publications (16)15.62 Total impact

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    ABSTRACT: Objective: The objective of this study was to assess whether adding isovoxel 3-dimensional T2-weighted imaging (volume isotropic T2-weighted acquisition [VISTA]) to multiparametric magnetic resonance imaging (mp-MRI) improves the ability to diagnose the extracapsular extension (ECE) of prostate cancer. Methods: Two radiologists independently evaluated ECE on images acquired with mp-MRI only (method A) and mp-MRI plus VISTA (method B) in 50 men who had undergone prostatectomy. We also compared the signal-to-noise ratio of the tumor on T2WI and VISTA scans. Results: Sensitivity, specificity, and accuracy were higher with method B. For both readers, specificity, accuracy, and the area under the receiver operating characteristic curve of method B were significantly higher than those of method A (reader 1: P = 0.028, 0.025, and 0.006; reader 2: P = 0.017, 0.0071, and 0.018). The signal-to-noise ratio was significantly higher on T2-weighted imaging than VISTA images (9.21 [SD, 2.46] vs 7.30 [SD, 1.87], P < 0.01). Conclusions: The addition of VISTA to mp-MRI improves the diagnostic value for ECE significantly.
    No preview · Article · Oct 2014 · Journal of computer assisted tomography
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    ABSTRACT: Purpose: Normalization of the apparent diffusion coefficient (ADC) may overcome ADC variability attributable to different patient and/or technical factors. The purpose of this study was to compare the efficacy of ADC and the normalized ADC (nADC) for differentiating between prostate cancer with a Gleason score (GS) = 6 and GS > 6 and to identify an optimum reference for nADC calculations. Materials and methods: Our study population comprised 58 patients who underwent diffusion-weighted MRI followed by radical prostatectomy. The nADC of the prostate cancer was calculated as ADC (cancer)/ADC (reference) by using the obturator internus muscle, urine in the bladder, and a 20-ml saline bottle placed on the groin as references. We performed receiver operating characteristic (ROC) analysis to identify the optimum reference for nADC calculations. Results: To differentiate between GS = 6 and GS > 6 prostate cancer, the area under the ROC curve of the nADC obtained with a saline bottle as reference was best (0.85) and significantly better than the area under the ADC ROC curve (0.71). Conclusions: nADC is superior to ADC for estimating the aggressiveness of prostate cancer. It is a noninvasive technique that aids in the selection of appropriate treatments.
    No preview · Article · Oct 2014 · Japanese journal of radiology
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    ABSTRACT: To evaluate long-term continuous administration of docetaxel (DOC), over survival rate, PSA level and adverse effects were analyzed, retrospectively. We also compared the results of long-term treatment group and short-term treatment group. This study reported that 14 cases of long-term continuous administration of DOC consisting of 11 or more cycles among 51 patients of castration-resistant prostate cancer (CRPC) treated with DOC from October 2008 to September 2013 at our institution, retrospectively. Nineteen patients who had treated with DOC 10 or less cycles were defined as short-term dose group, and both groups were compared. DOC was administered every 3 to 4 weeks at 60 to 70 mg/m2, and was treated with prednisolone at 10 mg/day as a general. The median number of treatment cycles was 15. Thirteen cases showed a decrease in PSA levels and 10 cases showed a decrease in PSA levels of 50% or more, the 1-year survival rate of long-term dose and short-term dose group were 100% and 16%. Adverse effects of grade 3 or lower consisted of leukocytopenia in 85% and thrombocytopenia in 28%, however, grade 4 or higher were not observed in long-term dose group. In multivariable analysis of parameters, long-term treatment was related to PSA levels at start of treatment and ALP levels. Forty-two percent of patients who have CRPC at our institution undergo long-term DOC based chemotherapy treatment It may be suggested that long-term DOC based chemotherapy for some cases contribute to extend survival time with no serious adverse events.
    Preview · Article · Oct 2014 · Nippon Hinyōkika Gakkai zasshi. The japanese journal of urology
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    ABSTRACT: Objective To assess the clinical negative predictive value (NPV) of multiparametric MRI (mp-MRI) for prostate cancer in a 5-year follow-up. Materials and Methods 193 men suspected of harboring prostate cancer with negative MRI findings were included. Patients with positive transrectal ultrasound (TRUS)-guided biopsy findings were defined as false-negative. Patients with negative initial TRUS-guided biopsy findings were followed up and only patients with negative findings by digital rectal examination, MRI, and repeat biopsy and no increase in PSA at 5-year follow-up were defined as “clinically negative”. The clinical NPV of mp-MRI was calculated. For quantitative analysis, mean signal intensity on T2-weighted images and the mean apparent diffusion coefficient value on ADC maps of the initial MRI studies were compared between peripheral-zone (PZ) cancer and the normal PZ based on pathologic maps of patients who had undergone radical prostatectomy. Results The clinical NPV of mp-MRI was 89.6% for significant prostate cancer. Small cancers, prostatitis, and benign prostatic hypertrophy masking prostate cancer returned false-negative results. Quantitative analysis showed that there was no significant difference between PZ cancer and the normal PZ. Conclusion The mp-MRI revealed a high clinical NPV and is a useful tool to rule out clinically significant prostate cancer before biopsy.
    No preview · Article · Oct 2014 · European Journal of Radiology
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    ABSTRACT: Objective: The purpose of our study was to identify low-risk prostate cancer on the basis of the D'Amico clinical risk score in patients with prostate-specific antigen (PSA) levels 10 ng/mL or less who had undergone radical prostatectomy by comparing apparent diffusion coefficient (ADC) with transrectal ultrasound (TRUS)-guided target biopsy. Materials and methods: In the preliminary study, we used receiver operating characteristic (ROC) analysis and determined the cutoff ADC to identify prostate cancer with a Gleason score of 6 or less for 117 patients. In the primary study, we assessed the combination of routine MRI (T2-weighted and diffusion-weighted imaging) plus the cutoff ADC value ("method A") to identify low-risk prostate cancer for another 89 patients. Their diagnostic value was compared with that of routine MRI combined with the Gleason score obtained from TRUS-guided target biopsies ("method B"). Results: The preliminary study showed that a mean ADC of 1.04 × 10(-3) mm(2)/s was the best cutoff. In the primary study, accuracy was statistically higher with method A for each reader (p = 0.041). Conclusion: In patients with PSA levels 10 ng/mL or less, the combination of MRI findings plus the cutoff ADC is significantly more accurate for the identification of low-risk prostate cancer than is the combination of MRI followed by TRUS-guided target biopsy.
    No preview · Article · May 2014 · American Journal of Roentgenology
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    ABSTRACT: PURPOSE To identify low-risk prostate cancer we retrospectively determined the optimal cutoff apparent diffusion coefficient (ADC) and compared the diagnostic value of the combination of routine MRI studies (T2- and diffusion-weighted images) plus the cutoff ADC with that of MRI followed by transrectal ultrasound (TRUS)-guided target biopsy in patients with PSA levels ≤ 10 ng/ml. METHOD AND MATERIALS In the preliminary study we used receiver operating characteristic (ROC) analysis and determined the cutoff ADC optimal for the identification of prostate cancer with a Gleason score (GS) ≤ 6 in 120 consecutive patients with PSA levels ≤ 10 ng/ml who had undergone radical prostatectomy. Our primary study included another 89 consecutive patients with PSA levels ≤ 10 ng/ml who were also treated by radical prostatectomy for pathologically-proved prostate cancer. Two radiologists independently assessed the combination of routine MRI studies plus the results of the cutoff ADC value (method A) for its diagnostic effectiveness in identifying prostate cancer classified as low-risk by the D’Amico clinical risk score (T stage ≤ T2a, GS ≤ 6, PSA ≤ 10 ng/ml). Their findings were then compared with the diagnostic value of routine MRI combined with the GS obtained from TRUS-guided target biopsies (method B) to identify the superior diagnostic method. RESULTS Our preliminary study showed that a mean ADC of 1.04 x 10-3 mm2/sec was the optimal cutoff for identifying prostate cancer with a GS ≤ 6 with an area under the ROC curve of 0.707. Under method A, sensitivity, specificity, PPV, NPV, and accuracy were 71.4%, 97.3%, 83.3%, 94.8%, and 93.3% for reader 1, and 71.4%, 94.7%, 71.4%, 94.7%, and 91.0% for reader 2, respectively. Under method B they were 57.1%, 89.3%, 50.0%, 91.8%, and 84.3% (reader 1) and 57.1%, 85.3%, 42.1%, 91.4%, and 80.9% (reader 2). For each reader accuracy was statistically higher with method A (p = 0.041). CONCLUSION In patients with PSA levels ≤ 10 ng/ml, the combination of MRI findings plus the cutoff ADC is significantly more accurate for the identification of low-risk prostate cancer than is the combination of MRI followed by TRUS-guided target biopsy. CLINICAL RELEVANCE/APPLICATION MRI study combined with ADC evaluation is highly useful for the detection of low-risk prostate cancer in patients with PSA levels ;10 ng/ml and avoids unnecessary invasive procedures including biopsy.
    No preview · Conference Paper · Dec 2013
  • K. Miyamae · K. Kitani · K. Hara · K. Nakakuma · Y. Hamada
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    ABSTRACT: A prospective study using subcutaneous drains was performed to determine whether subcutaneous drainage can reduce surgical site infection (SSI) following retropubic radical prostatectomy (RRP). The current study involved 25 patients who underwent radical prostatectomy at our institution between February and September, 2012. In addition, 130 patients who underwent radical prostatectomy between April and December, 2011 acted as a control group. Following surgery, the patients were observed for the appearance of any SSI, including wound separation, hematoma, seroma or infection. Incision and closure type were identical for all patients. Average age was 70.6 years old, average subcutaneous fat thickness was 2.7 cm, average body mass index was 25 kg/cm2, average length of surgery was 77 minutes, and average blood loss volume was 531 ml. Patients' white blood cell count and C-reactive protein levels were normal 7 days after the operation. The rate of SSI was 1.5 % in the control group and there were no significant differences between the control group and the current study group. However, as there were no incidences of SSI in the current study group, the results suggest that the use of subcutaneous drains in RRP may have been effective in preventing SSI.
    No preview · Article · May 2013 · Nishinihon Journal of Urology
  • Y. Hamada · K. Kitani

    No preview · Article · Apr 2012
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    ABSTRACT: We reviewed the characteristics of 25 pediatric patients (41 ureters) with primary vesico-ureteral reflux (VUR) who underwent anti-reflux surgery. The patients comprised 14 males and 11 females. The median age at diagnosis and at operation was 5 years 3 months and 6 years 5 months, respectively. VUR grade comprised grade I, 4 cases, grade II, 3 cases, grade III, 11 cases, grade IV, 11 cases and grade V, 12 cases. We utilized the Cohen method as the anti-reflux surgery technique. VUR recurrence was detected in 1 case (2.9%) during follow-up. Moreover, there were no cases with progressive renal dysfunction or breakthrough infection. The rate of kidney with renal scar on scintigraphy before the operation was 48.9%, and the rate of kidney with renal dysfunction before the operation was 60.0%. As a result of Fisher's exact probability test, the risk factors of BTI were high grade VUR and renal scar on scintigraphy. Based on our clinical results, our future strategy for the management of pediatric patients with primary VUR is proposed as follows. In all patients younger than 1 year old, antibacterial prophylaxis should be applied. For patients younger than 6 years old, the initial treatment should be antibacterial prophylaxis, but for patients with VUR of grade III or more, in cases of breakthrough infection or in cases with progressive renal dysfunction, surgical treatment should be considered. For patients older than 6 years with VUR of grade III or more, surgical treatment is strongly recommended.
    No preview · Article · Jan 2012 · Nishinihon Journal of Urology
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    ABSTRACT: To assess the diagnostic performance of diffusion-weighted magnetic resonance (MR) imaging (DWI) for prostate cancer detection, using different b-values. A total of 201 patients who underwent MR imaging before total prostatectomy were evaluated. MR images were independently assessed by three radiologists. Three combinations of sequences were separately evaluated, as follows: group 1 [T2-weighted images (T2WI) alone], group 2 (T2WI and DWI with a b-value of 1,000 s/mm2), group 3 (T2WI and DWI with a b-value of 2,000 s/mm2). Whole-mount-section histopathological examination was the reference standard. Areas under the receiver operating characteristic curve (AUCs) and diagnostic performance parameters were determined. The sensitivity, specificity, and AUC for the detection of prostate cancer were as follows: 52.2%, 80.7%, and 0.694 in group 1; 61.2%, 82.6%, and 0.755 in group 2; 73.2%, 89.7%, and 0.842 in group 3. Group 3 achieved the highest diagnostic performance, followed by group 2 (P<0.05). In the transition zone, the specificity was lower (P<0.001) for group 2 (82.2%) than for group 1 (86.2%). The addition of diffusion-weighted images with a b-value of 2,000 s/mm2 to T2WI can improve the diagnostic performance of MR imaging in prostate cancer detection.
    No preview · Article · Jan 2011 · European Radiology
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    ABSTRACT: We assessed the outcome after radical prostatectomy and pelvic lymphadenectomy for lymph node positive prostate cancer retrospectively. Furthermore, we compared the efficacy of immediate androgen deprivation adjuvant therapy in node positive patients who have undergone radical prostatectomy. We investigated 62 patients who have undergone radical prostatectomy and pelvic lymphadenectomy and have been found to have lymph node positive prostate cancer at our facility between January 1992 and January 2008. We researched the clinical stages, the pathological stages and Gleason scores for pathological pN1 + prostate cancer, retrospectively. The serum PSA levels were followed up every 6 months, and we considered that biochemical progression was PSA >0.4 ng/ml. We classified the groups treated with or without immediate androgen deprivation adjuvant therapy, the biochemical progression free survival and cause specific survival were analyzed by the Kaplan-Meier method, and the statistical significance was determined by the log rank test. The rate of lymph node positive patients who have undergone radical prostatectomy was 7.1%. The rate of 8 or greater in Gleason score of all the lymph node positive patients was 68.3%. The 5-year prostate cancer specific survival and 5-year biochemical progression free survival rates were 90.3 and 67.4% of all the patients. The biochemical progression free survival rate of the group of patients who have received immediate androgen deprivation therapy after radical prostatectomy was significantly higher than that of the group of patients who have not received immediately androgen deprivation therapy. It may be suggested that early androgen deprivation adjuvant therapy benefits patients with nodal metastases who have undergone radical prostatectomy and lymphadenectomy, compared with those who received deferred treatment, although in a retrospective nonrandomized study.
    No preview · Article · Jul 2009 · Nippon Hinyōkika Gakkai zasshi. The japanese journal of urology
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    ABSTRACT: Advances in high-precision radiation therapy techniques for patients with prostate cancer permit selective escalation of the radiation dose delivered to the dominant intraprostatic lesion and improve the therapeutic ratio. We evaluated the value of diffusion-weighted imaging (DWI) for dominant intraprostatic lesion assessment. The study population consisted of 23 patients with early prostate cancer. Before undergoing total prostatectomy, they were evaluated by means of magnetic resonance imaging, including DWI. T2-weighted imaging (T2WI) with and without DWI were retrospectively assessed by six independent observers. Imaging findings were compared with pathologic results from whole prostate specimens on a lesion-by-lesion basis. Pathologic study identified 43 lesions in 23 patients. On magnetic resonance imaging, the six observers correctly identified 11-22 of 43 lesions (sensitivity, 26-51%) on T2WI alone and 20-31 (sensitivity, 47-72%) on T2WI plus DWI. Positive predictive values were 42-73% on T2WI alone and 58-80% on T2WI plus DWI. For all observers, detection was higher on combined T2WI and DWI than on T2WI alone. Because the addition of DWI to T2WI improves the detectability of prostate cancer, DWI may offer a promising new approach for radiation therapy planning.
    No preview · Article · Dec 2008 · International journal of radiation oncology, biology, physics
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    ABSTRACT: The purpose of the present study was to evaluate the condition of urination and the International Prostate Symptom Score after radical prostatectomy. The cases of one hundred and ninety-two patients with prostate cancer who underwent radical prostatectomy at our facility between January 2005 and January 2007 were reviewed. The mean patients' age was 68.5 years old. Uroflowmetry and evaluation of I-PSS were performed before and 2 weeks, 6 months, and 12 months after the operation. The status of postoperative urinary incontinence was based on the patients' report. Maximal flow rate was decreased temporarily after radical prostatectomy. However, most patients had normal uroflowmetrogram at 6 months after the operation. I-PSS and QOL index was improved at 6 months after the operation. The findings from postoperative uroflowmetry and evaluation of I-PSS and QOL index turned worse temporarily, but they were improved 6 months after radical prostatectomy.
    No preview · Article · Nov 2008 · Nishinihon Journal of Urology
  • K. Miyamae · K. Kitani · K. Miyamoto · Y. Hamada · M. Kitaoka
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    ABSTRACT: We report a case of hemorrhagic adrenal cyst with infection. A 77-year-old woman was admitted with left flank pain and high fever. Abdominal CT revealed a left adrenal mass, 18 cm in diameter with regular margins, the contents of which were not enhanced with contrast medium. Abdominal MRI revealed that the majority of the adrenal mass had high-signal intensity and that some of the irregular contents of the lesion were not enhanced with contrast medium on T1-weighted MR images. Despite treatment with antibiotics, the high fever and pain persisted. According to these findings, the differential diagnosis was adrenal abscess or nonfunctional adrenal tumor. We performed transabdominal adrenalectomy, and the patients' condition improved soon after the operation. Pathological examination revealed a hemorrhagic adrenal cyst.
    No preview · Article · Jul 2008
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    ABSTRACT: A 25-year-old man had a painless swelling of the left testis and tarry stools. Chest radiography revealed multiple coin lesions suggestive of metastases. He was admitted to our hospital for the treatment of testicular tumor. He underwent left orchiectomy and histological examination of the resected testis showed non-seminomatous germ cell tumor (yolk-sac tumor and choriocarcinoma). Erythrocyte scintigraphy revealed the bleeding point from the jejunum tumor. Laparoscopic jejunectomy was performed and histological examination of the jejunum tumor showed metastasis of malignant germ cell tumor (choriocarcinoma). A computed tomography scan disclosed multiple foci suggestive of lung metastases, and tumor markers were found to be elevated (AFP 248.2 ng/ml (<15.0 ng/ml), β-HCG 5290 ng/ml (<0.2 ng/ml)). He was treated with two cycles of PEP (peplomycin, etoposide and cisplatin) and three cycles of EP (etoposide and cisplatin) resulting in normalization of AFP and β-HCG levels. CT scan showed residual lung metastases, so he underwent VATS (Video-Assisted Thoracoscopic Surgery) pneumonectomy and histological examination of the resected lung tumors showed no viable cells (necrotic tissue). However, β-HCG levels became elevated again, and he was then treated with two more cycles of EP resulting in normalization of β-HCG levels. The patient has been monitored for 14 months, during which time there has been no recurrence of the disease.
    No preview · Article · Aug 2006 · Nishinihon Journal of Urology
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    ABSTRACT: There were many case reports about bladder tamponade resulting from clots of blood. However, there were few reports about the clinical study that result from collecting cases of bladder tamponade. Thus, we performed a retrospective study about bladder tamponade resulting from clots of blood that we had managed. We investigated 20 patients who had bladder tamponade and were consulted at our facility between October 2002 and September 2005. We researched causes of the bleeding, characteristics of the patients, the laboratory data of coagulation system and treatments of our experience in managing patients. There were 17 males and 3 females. The average age of the patients was 74.0 years old. 8 cases took anticoagulant drugs, 6 cases had medical history of cerebral infarction or cardiac infarction, 4 cases took anticholinergic drugs and 9 cases had benign prostate hypertrophy or urethral stricture. Bleeding was due to bladder tumor in 9, prostate cancer in 1, radiation cystitis in 3, chronic cystitis in 1, malignant lymphoma in 1, idiopathic causes in 3 and unknown causes in 2 cases. Except 1 case, in all cases, evacuation of the clots was the first procedure followed by saline irrigation. This initial line of treatment was able to control the hemorrhage in 40% of the patients. For the remaining cases, transurethral coagulation and resection of bladder tumor were used as the second line treatment, and furthermore, radical cystectomy was performed in 1 case. Surgical treatments were required in 12 cases. Blood transfusion was required in 4 cases. According to progress aging society, the amounts of taken anticoagulant drugs and the patients who had lower urinary tract dysfunction may increase. It may be suggested that the cases of bladder tamponade resulting from clots of blood without bladder tumor or radiation cystitis tend to increase.
    Preview · Article · Aug 2006 · Nippon Hinyōkika Gakkai zasshi. The japanese journal of urology
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    ABSTRACT: A prospective longitudinal observation study was conducted, evaluating the quality of life (QOL) of patients before and after radical prostatectomy. For 65 patients who underwent radical prostatectomy at our facility between January and August 2003, QOL was evaluated immediately before surgery and at several points during the 6-month period after surgery. Health-related QOL was evaluated using SF-36 and FACT-G. Disease-specific QOL was evaluated using FACT-P and UCLA-PCI. In the evaluation using FACT-G, scores for social/family well-being showed no tendency of improvement until 6 months after surgery, while the other three items had improved to preoperative levels by the 6th postoperative month. In the evaluation using SF-36, the scores for role-emotional showed no tendency of improvement until 6 months after surgery. The score for general health perception remained unchanged during the survey period. The other 6 items tended to improve to their preoperative levels during the 6-month period after surgery. In the evaluation using FACT-P, QOL remained reduced throughout the 6-month period after surgery. In the evaluation using UCLA-PCI, the scores for urinary function became lowest immediately after surgery, but tended to improve thereafter during the 6-month period, although urinary function did not return to the preoperative level. The scores for bowel function and bowel bother had returned to their preoperative levels by the 6th month after surgery. The score for sexual function was low before surgery and it showed no improvement during the 6-month period after surgery. The score for sexual bother continued to decrease after surgery. In the evaluation of health-related QOL, scores for most items returned to their preoperative levels during the 6-month period after surgery, suggesting that health-related QOL improves rapidly after surgery. For evaluation of disease-specific QOL, UCLA-PCI seems to be particularly useful since this index allows the detailed evaluation of QOL to be divided into urinary, bowel and sexual function and bother. Furthermore, it would seem to be essential to continue the evaluation of disease-specific QOL for a period of more than 6 months.
    No preview · Article · Jan 2004