Shuichiro Kobayashi

Tokyo Medical and Dental University, Tokyo, Tokyo-to, Japan

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Publications (18)18.7 Total impact

  • Article: Impact of bladder neck involvement on progression in patients with primary non-muscle invasive bladder cancer: A prospective validation study.
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    ABSTRACT: PURPOSE: Our previous retrospective study reported that bladder neck involvement (BNI), as well as tumor grade and stage, was a significant risk factor for progression in primary non-muscle invasive bladder cancer (NMIBC). We prospectively validated BNI as a significant predictor for progression using a new cohort of patients with primary NMIBC. PATIENTS AND METHODS: A total of 297 new Japanese patients who underwent transurethral resection and were pathologically diagnosed with Ta or T1 urothelial carcinoma were enrolled in this prospective study. Clinicopathologic data were collected at study entry. Multivariate Cox proportional hazards regression models were performed to identify the independent predictors for progression. A predictive scoring model for progression was developed using the regression coefficients (RCs) from the final multivariate model. The predictive ability of the model was assessed using Harrell's c-index. RESULTS: With a median follow-up of 37 months, 16 patients (5.4%) progressed. Progression probability at 1 and 5 years were 1.5% and 8.0%, respectively. Multivariate analysis revealed that histologic grade 3 (hazard ratio [HR] 9.45, P = 0.0004, RC 2.25), pathologic T1 stage (HR 6.91, P = 0.0014, RC 1.93), and BNI (HR 11.75, P = 0.0009, RC 2.46) were all independent predictors of progression. When all 3 variables were scored as 1 point and the patients were divided into 3 groups, progression rates were clearly discriminated (P<0.0001). The c-index was 0.80. CONCLUSIONS: This prospective validation study has shown that BNI is a significant prognostic factor for progression in primary NMIBC. The scoring model including BNI enables the physician to classify patients with primary NMIBC into 3 groups with clearly different progression rates.
    Urologic Oncology 05/2013; · 3.22 Impact Factor
  • Article: Apparent diffusion coefficient value reflects invasive and proliferative potential of bladder cancer.
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    ABSTRACT: PURPOSE: To elucidate a role of apparent diffusion coefficient (ADC) value as a biomarker of bladder cancer, we investigated its associations with Ki-67 labeling index (LI) along with classical clinicopathological prognosticators. MATERIALS AND METHODS: Diffusion-weighted MRI (DW-MRI) at 1.5 Tesla using b-values of 0, 500, 1000, and 2000 s/mm(2) was prospectively taken before transurethral resection by 132 bladder cancer patients. ADC value of index tumors was measured and compared with clinicopathological prognosticators including Ki-67 LI. RESULTS: ADC value was significantly lower in tumors with higher Ki-67 LIs, sessile tumors (versus papillary), larger tumors, higher grade disease, and higher T stage disease. ADC value inversely correlated with Ki-67 LI (ρ = -0.57; P < 0.0001). On multiple regression analysis, T stage and Ki-67 LI significantly correlated with ADC value. The Akaike information criterion confirms these two parameters constitute the best model for determining ADC value. Similarly, T stage and ADC value significantly correlated with Ki-67 LI and these two parameters composed the best model for predicting Ki-67 LI. CONCLUSION: ADC value would reflect T stage and Ki-67 LI, representing invasive and proliferative potential, respectively. ADC value is likely to serve as a biomarker reflecting aggressiveness of bladder cancer. J. Magn. Reson. Imaging 2013. © 2013 Wiley Periodicals, Inc.
    Journal of Magnetic Resonance Imaging 04/2013; · 2.70 Impact Factor
  • Article: Apparent diffusion coefficient as a prognostic biomarker of upper urinary tract cancer: a preliminary report.
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    ABSTRACT: OBJECTIVES: To investigate the role of apparent diffusion coefficient (ADC) as a biomarker reflecting the aggressiveness of upper urinary tract urothelial cell carcinoma (UUT-UCC). METHODS: Thirty-four consecutive patients treated with nephroureterectomy for non-metastatic disease were prospectively enrolled in this study. ADC was compared with clinicopathological variables including Ki-67 labelling index (LI) and cancer-specific survival (CSS). RESULTS: The overall 3-year CSS rate was 82 % (median follow-up, 36 months). ADC was significantly lower in grade 3 disease than in grades 1-2 disease (P = 0.011) and significantly and inversely correlated with Ki-67 LI (ρ = -0.59, P = 0.0002). Low ADCs (<1.10 × 10(-3) mm(2)/s) were significantly associated with shorter CSS (P = 0.039). Multivariate analysis of preoperative variables identified ADC and MRI-based clinical T stage as independent indicators of shorter CSS; the patients were stratified into high-risk (8 patients with low ADC and at least clinical T3) and low-risk (26 patients with high ADC or not more than clinical T2) groups with 3-year CSS rates of 43 % and 93 % (P = 0.0003). CONCLUSIONS: Our preliminary data suggest the potential role of ADC as a quantitative biomarker reflecting the aggressiveness of UUT-UCC. ADC might be useful for preoperative risk stratification of UUT-UCC patients. KEY POINTS : • Diffusion-weighted MRI offers new information about the aggressiveness of urinary tract cancers. • The apparent diffusion coefficient acts as a quantitative biomarker for upper urinary tract cancers. • ADC inversely correlates with immunohistochemical and histological grading of UUT-UCC. • ADC offers a prognosis for UUT-UCC patients treated with nephroureterectomy.
    European Radiology 03/2013; · 3.22 Impact Factor
  • Article: Role of diffusion-weighted magnetic resonance imaging in predicting sensitivity to chemoradiotherapy in muscle-invasive bladder cancer.
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    ABSTRACT: In chemoradiation (CRT)-based bladder-sparing approaches for muscle invasive bladder cancer (MIBC), patients who respond favorably to induction CRT enjoy the benefits of bladder preservation, whereas nonresponders do not. Thus, accurate prediction of CRT sensitivity would optimize patient selection for bladder-sparing protocols. Diffusion-weighted MRI (DW-MRI) is a functional imaging technique that quantifies the diffusion of water molecules in a noninvasive manner. We investigated whether DW-MRI predicts CRT sensitivity of MIBC. The study cohort consisted of 23 MIBC patients (cT2/T3 = 7/16) who underwent induction CRT consisting of radiotherapy to the small pelvis (40 Gy) with two cycles of cisplatin (20 mg/day for 5 days), followed by partial or radical cystectomy. All patients underwent DW-MRI before the initiation of treatment. Associations of apparent diffusion coefficient (ADC) values with CRT sensitivity were analyzed. The proliferative potential of MIBC was also assessed by analyzing the Ki-67 labeling index (LI) in pretherapeutic biopsy specimens. Thirteen patients (57%) achieved pathologic complete response (pCR) to CRT. These CRT-sensitive MIBCs showed significantly lower ADC values (median, 0.63 × 10(-3) mm(2)/s; range, 0.43-0.77) than CRT-resistant (no pCR) MIBCs (median, 0.84 × 10(-3) mm(2)/s; range, 0.69-1.09; p = 0.0003). Multivariate analysis identified ADC value as the only significant and independent predictor of CRT sensitivity (p < 0.0001; odds ratio per 0.001 ×10(-3) mm(2)/s increase, 1.03; 95% confidence interval, 1.01-1.08). With a cutoff ADC value at 0.74 × 10(-3) mm(2)/s, sensitivity/specificity/accuracy in predicting CRT sensitivity was 92/90/91%. Ki-67 LI was significantly higher in CRT-sensitive MIBCs (p = 0.0005) and significantly and inversely correlated with ADC values (ρ = -0.67, p = 0.0007). DW-MRI is a potential biomarker for predicting CRT sensitivity in MIBC. DW-MRI may be useful to optimize patient selection for CRT-based bladder-sparing approaches.
    International journal of radiation oncology, biology, physics 03/2012; 83(1):e21-7. · 4.59 Impact Factor
  • Article: [Transurethral lithotripsy with rigid and flexible ureteroscopy for renal and ureteral stones: results of the first 100 procedures].
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    ABSTRACT: We evaluated the clinical outcome of transurethral lithotripsy (TUL) using rigid & flexible ureteroscopy and holmium : yttrium-aluminum-garnet (YAG) laser in our hospital. We retrospectively reviewed 100 consecutive transurethral lithotripsy procedures performed on 82 patients from May 2008 to June 2010 at our hospital. Twenty-five patients (30%) had multiple stones and 10 patients (12%) had bilateral stones. The main stones were located in the renal pelvis, ureteropelvic junction, upper ureter, middle ureter, and lower ureter in 14, 12, 26, 3, and 27 cases, respectively. Median operative time was 75 minutes (range, 18-238 minutes). Operative complications were 5 cases of pyelonephritis and 1 case of ureteral perforation that was managed conservatively with percutaneous nephrostomy. The average number of procedures was 1.22 with 65 patients requiring one, 16 requiring two, and 1 requiring three procedures. Three patients had shock wave lithotripsy (SWL) and two patients had minipercutaneous nephrolithotomy (mini-PNL) after first TUL. However, all of these patients eventually needed additional TUL. The overall success rate was 99% (81/82). Rigid & flexible ureteroscopy and holmium : YAG laser lithotripsy achieved excellent results of treatment for urolithiasis. TUL gave a high stone-free rate with low complication rates. In Japan, where shock wave lithotripters are widely used, trend of treatment for urolithiasis will shift from SWL to TUL.
    Hinyokika kiyo. Acta urologica Japonica 08/2011; 57(8):411-6.
  • Article: Diagnostic performance of diffusion-weighted magnetic resonance imaging in bladder cancer: potential utility of apparent diffusion coefficient values as a biomarker to predict clinical aggressiveness.
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    ABSTRACT: The diagnostic performance of diffusion-weighted magnetic resonance imaging (DW-MRI) in bladder cancer and the potential role of apparent diffusion coefficient (ADC) values in predicting pathological bladder cancer phenotypes associated with clinical aggressiveness were investigated. One hundred and four bladder cancer patients underwent DW-MRI and T2-weighted magnetic resonance imaging (T2W-MRI) before transurethral resection. The image sets were reviewed by two independent radiologists. ADC values were measured in 121 eligible tumours. In detecting patients with bladder cancer, DW-MRI exhibited high sensitivity equivalent to that of T2W-MRI (>90%). Interobserver agreement was excellent for DW-MRI (κ score, 0.88) though moderate for T2W-MRI (0.67). ADC values were significantly lower in high-grade (vs. low-grade, P < 0.0001) and high-stage (T2 vs. T1 vs. Ta, P < 0.0001) tumours. At a cut-off ADC value determined by partition analysis, clinically aggressive phenotypes including muscle-invasive bladder cancer (MIBC) and high-grade T1 disease were differentiated from less aggressive phenotypes with a sensitivity of 88%, a specificity of 85% and an accuracy of 87%. DW-MRI exhibits high diagnostic performance in bladder cancer with excellent objectivity. The ADC value could potentially serve as a biomarker to predict clinical aggressiveness in bladder cancer.
    European Radiology 06/2011; 21(10):2178-86. · 3.22 Impact Factor
  • Article: [A case of metastatic paratesticular rhabdomyosarcoma in an adult successfully treated with multidrug combination chemotherapy].
    Shuichiro Kobayashi, Tetsuro Tsukamoto, Tsuguhiro Tohma
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    ABSTRACT: A 20-year-old man was referred to our hospital with the complaint of a mass in the left scrotum. Computed tomography showed retroperitoneal lymph node metastases and multiple lung metastases. He underwent left high orchiectomy and was diagnosed with paratesticular embryonal rhabdomyosarcoma. He received combination chemotherapy consisting of cyclophosphamide, vincristine, doxorubicin, and dacarbazine. After four cycles of chemotherapy, lung metastases disappeared and lymph nodes decreased dramatically. He was alive without recurrence 31 months after the operation.
    Hinyokika kiyo. Acta urologica Japonica 09/2010; 56(9):531-3.
  • Article: [Estramustine phosphate withdrawal syndrome in relapsed prostate cancer: two case reports].
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    ABSTRACT: The decrease of the level of serum prostate specific antigen (PSA) after discontinuation of estramustine phosphate (EMP) has rarely been reported. We report 2 cases in whom EMP withdrawal syndrome was encountered. Case 1 was a 68-year-old man with a complaint of paresis of lower limbs. He was diagnosed with prostate cancer with multiple bone metastases. The serum PSA level was 9,300 ng/ml. He was treated with luteinizing hormone-releasing hormone agonist (LH-RHa) and bicalutamide (BCL). Six months later, EMP was started against PSA failure. During the 3-year treatment with EMP, PSA decreased to the nadir of 0.7 ng/ml and gradually increased to 14 ng/ml. After withdrawal of EMP, PSA decreased to 0.3 ng/ml (97.9% decline) and remained at this level for 4 months. Case 2 was a 61-year-old man who visited our hospital with gross hematuria. Transurethral bladder biopsy and transrectal prostate biopsy were performed. The diagnosis was moderately differentiated adenocarcinoma of the prostate that invaded to the bladder. Computed tomography (CT) showed a lymph node metastasis. He was treated with LH-RHa and BCL. The treatment was changed to EMP after PSA failure. EMP was withdrawn when PSA was 30 ng/ml. Then PSA decreased to less than 0.2 ng/ml (99% decline) and remained at this level for 9 months. We consider that in patients with EMP-resistant progression, EMP withdrawal syndrome should be checked.
    Hinyokika kiyo. Acta urologica Japonica 06/2008; 54(6):423-6.
  • Article: [A case of adenocarcinoma of the urinary bladder arising 45 years after ileal replacement of ureter for tuberculous ureteral stricture].
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    ABSTRACT: We report a case of adenocarcinoma arising in the urinary bladder 45 years after ileal replacement of ureter for tuberculous ureteral stricture. A 65-year-old man was admitted with gross hematuria. Cystoscopic examination demonstrated a broadbased non-papillary tumor on the left posterior wall of the bladder and a papillary tumor at the anastomotic site between the bladder and ileal segment. Total cystectomy and construction of ileal conduit were performed. The histopathological examination demonstrated well differentiated adenocarcinoma of the bladder and ileal ureter. Intestinal metaplasia widely infiltrated into the bladder epithelium around the anastomotic site.
    Hinyokika kiyo. Acta urologica Japonica 04/2008; 54(3):235-8.
  • Article: Preventive effect of risedronate on bone loss in men receiving androgen-deprivation therapy for prostate cancer.
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    ABSTRACT: Androgen-deprivation therapy for prostate cancer decreases bone mineral density and increases the risk of fracture. The effect of risedronate, a potent third-generation oral bisphosphonate, on bone loss during androgen deprivation therapy was investigated. Sixty-one prostate cancer patients with a mean age (+/- SD) of 79 +/- 6 years who had received androgen deprivation therapy for 42 +/- 29 months were enrolled, and were treated with 2.5 mg of risedronate daily for six months. Bone mineral density was measured at the femoral neck, lumbar spine, and ultradistal radius by dual energy X-ray absorptiometry. The percent change of bone mineral density after treatment with risedronate was calculated as the primary efficacy variable. Urinary N-telopeptide of type I collagen was measured as a bone resorption marker. Bone mineral density remained stable in the femoral neck and radius during risedronate therapy. In contrast, the bone mineral density of the lumbar spine showed a significant increase from 1069 +/- 488 mg/cm(2)-1112 +/- 497 mg/cm(2) (P < 0.001), representing a gain of 4.9 +/- 8.9%. Urinary N-telopeptide of type I collagen decreased significantly (P < 0.001) after three months of risedronate treatment. Risedronate could prevent and reverse bone loss in men receiving androgen deprivation therapy for prostate cancer by inhibiting bone resorption.
    International Journal of Urology 12/2007; 14(12):1071-5. · 1.75 Impact Factor
  • Article: [A case of non-traumatic rupture of varicocele].
    Shuichiro Kobayashi, Tatsuya Machida, Kazuhiro Ishizaka
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    ABSTRACT: We report a case of a non-traumatic rupture of varicocele. A 28-year-old man visited our hospital complaining of left scrotal swelling with severe spontaneous pain of sudden onset after straining for defecation. MRI revealed a dilated spermatic cord with scrotal hematoma surrounding the left testis, which leads to the diagnosis of varicocele rupture. Conservative treatment with oral analgesics for a couple of weeks relieved the swelling and pain. Subinguinal microscopic ligation of left spermatic veins was performed 4 months later.
    Nippon Hinyōkika Gakkai zasshi. The japanese journal of urology 10/2006; 97(6):801-3.
  • Article: [5 years intravesical instillation with mitomycin-C and pirarubicin as a prophylactic treatment for superficial bladder cancer].
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    ABSTRACT: We studied prophylactic intravesical instillation of mitomycin C (MMC) and pirarubicin (THP) following transurethral resection of bladder tumor (TUR-Bt) for superficial bladder cancer. Forty-six evaluable patients were administered intravesically 20 mg of MMC dissolved in 20 ml saline on day 1 and 20 mg of THP dissolved 20 ml 5% dextrose on day 2. The patients were followed up by cystscopy and urinary cytology. Intravesical instillations were performed once a month and continued for 5 years. The non-recurrence rates at 1, 3 and 5 years were 88.8%, 79.5% and 67.0%, respectively. No significant differences were observed between grade 1-2 and 3, male and female, and solitary and multiple tumors. Although the side effects were relatively mild, 6 patients were stopped intravesical instillation. Because non-recurrence rates of our report is not better than previous reports with shorter treatment periods, intravesical MMC and THP instillation for 5 years is not beneficial to the patients with superficial bladder cancer.
    Nippon Hinyōkika Gakkai zasshi. The japanese journal of urology 06/2006; 97(4):636-41.
  • Article: [Long-term survival in patients with metastatic renal cell carcinoma managed with conservative therapy: a report of two cases].
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    ABSTRACT: Case 1. A 58-year-old man underwent radical nephrectomy due to a tumor in the left kidney (renal cell carcinoma, clear cell subtype, G3, pT1bpN0) in 1988. Thirteen years later, he underwent surgical resection of metastases to lung and cerebrum and gamma ray knife resection of two other sites of metastases to cerebrum in 2001. He had no evidence of disease in April, 2003. Case 2. A 53-year-old man underwent radical nephrectomy due to a tumor in the right kidney (renal cell carcinoma, clear cell type, pT1apN0) in 1987. From 1996 to 2001, irradiation therapy to multiple metastases to thoracic vertebrae (50 Gy), rib (50 Gy), para-aorta lymph nodes (40 Gy), sacrum (44 Gy) and sternum (44 Gy), and surgical resection of dermal metastasis were performed. Paraplegia occurred due to regrowth of thoracic bone metastasis in December, 2001. In February, 2002, he died of septic shock caused by infection of decubitus. Surgical resection and palliative therapy of recurrent metastatic foci was useful to improve the quality of life and probably prognosis.
    Hinyokika kiyo. Acta urologica Japonica 10/2004; 50(9):621-4.
  • Article: [Alveolar rhabdomyosarcoma originating in spermatic cord: a case report].
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    ABSTRACT: A 19-year-old man visited our hospital complaining of swelling of the left inguinal region. A thumb head-sized tumor was palpated through the skin on the left spermatic cord. Tumor resection was performed because it was dissected easily apart from the left spermatic cord. Pathological examination revealed alveolar rhabdomyosarcoma with positive surgical margin. Computed tomographic scanning revealed no retroperitoneal lymph node swelling, and there were no clinical findings of distant metastasis (clinical stage I). Radical inguinal orchiectomy with combined chemotherapy using vincristine, dactinomycin, and ifosfamide (VAI) was performed. He has been alive without any recurrence for 8 years and 8 months after the surgery.
    Hinyokika kiyo. Acta urologica Japonica 10/2004; 50(9):653-5.
  • Article: [A case of non-functioning adrenocortical adenoma associated with renal cell carcinoma].
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    ABSTRACT: Left renal and left adrenal masses were incidentally found by computerized tomography (CT) in a 56-year-old man who was admitted to our hospital for treatment of upper digestive tract hemorrhage. Apparently no clinical signs suggestive of Cushing's syndrome existed. The renal tumor was diagnosed as renal cell carcinoma based on the findings on enhanced CT. 131I-adosterol uptake in the examination of adrenal scintigraphy under dexamethasone suppression was definitely increased in the left adrenal gland, although hormonal examinations of serum and urine for adrenal functions were within the normal range. Plasma adrenocorticotropic hormone (ACTH) and serum cortisol were suppressed by administration of 2 mg dexamethasone for 2 days. The left kidney was radically removed by surgery together with the left adrenal gland. Histological diagnoses were left renal cell carcinoma and adrenocortical adenoma.
    Hinyokika kiyo. Acta urologica Japonica 11/2003; 49(10):607-9.
  • Article: [Transitional cell carcinoma of the urinary bladder accompanied by signet-ring cell carcinoma: a case report].
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    ABSTRACT: A 58-year-old man visited our clinic with complaints of gross hematuria and pollakisuria. Cystoscopic examination revealed multiple non-papillary broad based tumors and reddish unstable mucosa in the bladder. The pathological specimen of the transurethral biopsy of the tumors showed signet-ring cell carcinoma predominantly and adenocarcinoma transforming into signet-ring cell carcinoma partially. A total cystectomy with ileal conduit urinary diversion was performed. The histopathological finding of the radical cystectomy specimen was grade 3 transitional cell carcinoma accompanied by adenocarcinoma. These findings suggest that the adenomatous metaplasia of transitional cell carcinoma in the bladder could differentiate into signet-ring cell carcinoma.
    Hinyokika kiyo. Acta urologica Japonica 08/2003; 49(7):411-3.
  • Article: [A case of giant perineal epidermal cyst: a case report].
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    ABSTRACT: A 33-year-old man was admitted to our hospital with the chief complaint of a giant perineal mass causing difficulty in walking. Magnetic resonance imaging revealed cystic tumor with a diameter of 13 cm. We performed tumor resection. Histopathological diagnosis of the tumor was epidermal cyst. To our knowledge, this is the sixth case of perineal epidermal cyst reported in Japan.
    Hinyokika kiyo. Acta urologica Japonica 06/2003; 49(5):257-9.
  • Article: [A case of fibroepithelial ureteral polyp in an adult patient].
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    ABSTRACT: A 24-year-old man complaining of asymptomatic gross hematuria was referred to our hospital for treatment of bilateral hydronephroses (left > right) diagnosed at a previous clinic. Radiological examinations demonstrated a filling defect at the left uretero-pelvic junction. Cytological examination of the urine was negative. With the diagnosis of suspected benign ureteral polyp, the patient underwent endoscopic-assisted partial ureterectomy and pyeloplasty through a 5 cm flank incision. Histological examination revealed that the villous tumor in the ureter was a fibroepithelial polyp.
    Hinyokika kiyo. Acta urologica Japonica 03/2003; 49(3):161-3.