Biomedical subjects

Masahiro Yanase

Publications and source records attributed to Masahiro Yanase.

9 recordsLinked to original sources

PubMed2006

Preoperative computed tomography finding predicts for postoperative inguinal hernia: new perspective for radical prostatectomy-related inguinal hernia.

OBJECTIVES: To investigate the incidence of radical prostatectomy-related inguinal hernia (RPRIH) and the predictive factors for RPRIH. METHODS: We reviewed the medical charts of patients who had undergone retropubic radical prostatectomy (RRP) at our institution from January 2002 to December 2004 and had a median follow-up of 17 months (range 3 to 42). All patients were examined for RPRIH every 3 months. We also reviewed the computed tomography results in a blinded manner and investigated the predictive factors for RPRIH with multivariate analysis using the Cox proportional hazards model. RESULTS: Of 98 patients analyzed, 17 were diagnosed with RPRIH after RRP (17.3%) at the median of 7 months (range 3 to 12). Preoperative computed tomography results were available for all patients, and subclinical inguinal hernia was identified in 20 (20.4%) of the 98 patients. Multivariate analysis showed that a subclinical inguinal hernia was the single predictive factor for RPRIH. The estimated rate of RPRIH was 60.6% in the subclinical inguinal hernia group and 9.5% in the normal group at 12 months (log-rank test, P <0.001). CONCLUSIONS: The results of the present study have indicated that a preoperative computed tomography finding of a subclinical inguinal hernia predicts for postoperative inguinal hernia formation after RRP. RRP might only advance the time at which the inguinal hernia would develop with or without surgery. Thus, all patients with a subclinical inguinal hernia finding should be informed about the possibility of the development of RPRIH within 12 months after RRP and recommended to undergo surgical repair at RRP.

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PubMed2005

[Tumor size and regional lymph node metastasis in patients with M0 renal cell carcinoma: analysis in those having regional lymph node dissection].

We evaluated the relationship between regional lymph node metastasis and tumor size in patients with M0 renal cell carcinoma who received regional lymph node dissection. The study involved 234 of the 247 patients with localized renal cell carcinoma who underwent radical nephrectomy with lymph node dissection at our institute between 1985 and 1999. Patients were arbitrarily classified into 3 groups by the greatest diameter of the tumor on preoperative computed tomography (CT): 4.0 cm or less (group A), 4.1 to 7.0 cm (group B), and 7.1 cm or more (group C). The incidence of lymph node metastasis was assessed in each group. The current study showed that 11 (4.7%) of the 234 patients with lymph node dissection together with radical nephrectomy were lymph node positive. The incidences of lymph node metastasis were 4.0% in group A, 2.3% in group B, and 8.4% in group C (p = 0.79). Of these 11 patients with lymph node metastasis, 2 (18.2%) have so far survived for over 5 years following surgery. Although the role of regional lymph node dissection with radical nephrectomy might be limited and controversial in renal cell carcinoma, urological surgeons should always be aware of possible metastasis for any tumor size.

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PubMed2004

Erectile function following external beam radiotherapy for clinically organ-confined or locally advanced prostate cancer.

BACKGROUND: External beam radiotherapy (XRT) has been a standard treatment for clinically localized prostate cancer. However, preservation of erectile function following XRT is controversial. In this study, the influence of XRT on erectile function of patients with clinically organ-confined or locally advanced prostate cancer was retrospectively evaluated. METHODS: The study included 34 of 84 patients with organ-confined or locally advanced prostate cancer who underwent XRT between 1995 and 2002. Erectile function following radiotherapy was assessed by a simple mailed questionnaire that was constructed for the study. To determine the predictive factors for erectile dysfunction following radiotherapy, data were analyzed by multivariate analysis with the Cox proportional hazards model. RESULTS: The modality of XRT was the only factor to independently predict erectile dysfunction following XRT. The maintenance rates of erectile function were 47.6% at 1 year and 19% at 3 years in patients who received the 3-dimensional conformal radiotherapy, which were significantly higher than in those who received conventional radiotherapy (P = 0.026). CONCLUSIONS: XRT significantly reduced the maintenance rate of erectile function during the follow-up period, with the rate being 19% at 3 years in patients who received 3-dimensional conformal radiation. The XRT modality was involved in the reduction of erectile function. These results suggest that erectile dysfunction is a possible adverse event following XRT.

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PubMed2004

Partial nephrectomy for small localized renal cell carcinoma.

We retrospectively reviewed the records of 54 patients with RCC who underwent partial nephrectomy for the primary lesion between 1992 and 2001. The indications for partial nephrectomy were elective in 43 and imperative in 11 patients. We selected 51 patients with clinical stage T1a who underwent open radical nephrectomy for localized RCC for comparison during the same period. We evaluated the peri- and postoperative complications, disease-free survival rates and changes of renal function in the partial nephrectomy (PN) group, compared to the radical nephrectomy (RN) group. There was no significant difference with regard to pathological findings and clinical outcomes between two groups, except for the amount of intraoperative bleeding. Three patients in the PN group developed postoperative complications, consisting of urine leakage in 2 patients and renal hypertension in 1 patient. The 5-year disease-free survival rates in the PN and RN groups were 90% and 97%, respectively. Local recurrence from the resected area of the renal parenchyma was not found in patients in the PN group. All patients in the PN group maintained satisfactory and stable renal function. In the RN group, renal function slowly deteriorated in 2 patients. Therefore, partial nephrectomy offers cancer control and an acceptable low mortality rate, comparable to those of radical nephrectomy.

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PubMed2004

Clinical course in patients with percutaneous nephrostomy for hydronephrosis associated with advanced cancer.

We investigated the clinical courses of 33 patients with advanced malignancies who has undergone percutaneous nephrostomy (PNS) to clarify the efficacy and validity of PNS and evaluated the results according to the type of catheter. The pigtail, Malecot and balloon catheters were used. All the catheters were exchanged every 4 weeks, if necessary for larger ones. The site of the primary disease, preoperative performance status, duration of time spent at home after PNS construction, number of times the catheter was changed, type and size of the catheter and complications associated with PNS were compiled. The median overall survival was 3.0 months. Twenty-three patients (69.7%) were never discharged from hospital. Thirty patients died of their primary diseases. The median overall survival of patients with cancers of the upper gastrointestinal system, large bowel, urological organs and gynecologic organs were 1.5, 5.5, 3.0 and 3.0 months, respectively (p=0.0116). Eighteen patients (54.5%) experienced complications such as pyelonephritis, obstruction, dislodgement and so on. PNS is an appropriate urinary diversion for patients with hydronephrosis with advanced cancer and unilateral construction is effective for treating end-stage obstructive renal failure. However, PNS rarely improves the patient's quality of life and the risk of complications is unavoidable regardless of the type of catheter used.

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PubMed2003

Cell proliferation, apoptosis, angiogenesis and growth rate of incidentally found renal cell carcinoma.

BACKGROUND: Our previous study showed that the growth rate of incidentally found renal cell carcinoma (RCC) varied, and that the initial clinical and pathological features did not predict subsequent growth of the carcinoma. The objective of this study was to determine the relationships between cell proliferation, apoptosis, angiogenesis and the growth rates of these RCC. METHODS: We examined cell proliferation, apoptosis, and angiogenesis in 16 incidentally found cases of RCC. Cell proliferation was assessed by immunohistochemical staining with a Ki-67 antibody. Apoptosis was assessed by the terminal deoxynucleotidyl transferase (TdT) mediated deoxy-UTP biotin nick end labeling (TUNEL) technique. The Ki-67 labeling index (KI) and the apoptotic index (AI) were determined as the ratio of immunohistochemically positive cells per 1000 cancer cells. The KI/AI ratio was also determined. Angiogenesis was evaluated by CD34 immunostaining. Finally, we investigated the correlation between these parameters and the growth rate of primary lesions of incidentally found RCC. RESULTS: The KI ranged from 7 to 73 (median, 20), AI ranged from 6 to 171 (median, 26), and microvessel density (MVD) ranged from 21 to 673 (median, 265) for incidentally found RCC. Ki-67 labeling index, AI and MVD were not closely correlated to each other. Furthermore, these parameters were not associated with growth rates of incidentally found RCC. Only the KI/AI ratio was strongly correlated to the growth rate of incidentally found RCC (r = 0.709; P = 0.0083). CONCLUSION: Our results suggest that the balance between cell proliferation and apoptosis partly determines the growth rate of primary lesions of incidentally found RCC.

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PubMed2003

External beam radiation monotherapy for localized or locally advanced prostate cancer.

PURPOSE: We report the treatment results and complications of external beam radiation monotherapy for localized or locally advanced prostate cancer patients. METHODS: Fifty-four patients with T(1b-3a)N(0)(pN(0))M(0) prostate cancer were treated with external beam radiation monotherapy between 1989 and 2001 at four institutes. RESULTS: During the 4-122 month follow-up period (median: 25 months), 11 (20%) patients experienced biochemical failure, including one with simultaneous local recurrence. The 2-year actuarial biochemical control rate was 85%. Univariate analysis showed that the clinical T classification (P = 0.01), Gleason score (P = 0.006), pretreatment PSA (P = 0.02) and PSA nadir value (P = 0.01) were associated with a higher probability of biochemical failure. Multivariate analysis using the Cox proportional hazards model demonstrated that only the PSA nadir value was a strong predictor of PSA recurrence (P < 0.01). Adverse events were mild and tolerable. No severe urinary or bowel complications were observed. CONCLUSIONS: External beam radiation monotherapy is effective for clinically organ-confined prostate cancer with a low incidence of severe complications in a mean follow-up period of 2 years.

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PubMed2002

Recurrence of renal cell carcinoma more than 5 years after nephrectomy.

OBJECTIVES: We evaluated clinical features and predictive factors for the recurrence of renal cell carcinoma (RCC) developing more than 5 years after nephrectomy. METHODS: We retrospectively reviewed 239 patients with RCC who underwent surgery for the primary lesion. To identify factors that affected recurrence more than 5 years after nephrectomy (delayed recurrence) and its clinical outcomes, we performed a multivariate analysis using Cox's proportional hazards model and a survival study. RESULTS: Recurrence developing within 5 years after nephrectomy (early recurrence) was found in 57 patients and delayed recurrence in 11 patients. The multivariate analysis revealed no clinical and pathologic features influencing delayed recurrence in 114 patients who survived more than 5 years after nephrectomy without having early recurrence. The patients with delayed recurrence showed better clinical outcomes than those with early recurrence when the rate was determined from the time of recurrence. CONCLUSIONS: Although delayed recurrence is not a rare event for patients with RCC, no clinical and pathologic factors at the time of the initial treatment can predict the recurrence. Patients who are free of recurrence for more than 5 years after surgery for a primary lesion should be carefully followed up for delayed recurrence.

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PubMed2002

Does transurethral resection of the prostate facilitate detection of clinically significant prostate cancer that is missed with systematic sextant and transition zone biopsies?

BACKGROUND: A prospective study was conducted to determine whether transurethral resection of the prostate (TURP) facilitates detection of prostate cancer that is missed with systematic sextant biopsies associated with transition zone (TZ) biopsies. METHODS: A total of 139 consecutive patients underwent transperineal TZ biopsies of each lobe in addition to a transrectal systematic sextant peripheral zone (PZ) biopsy. Patients whose biopsies were negative for cancer received TURP for relief of lower urinary tract obstruction when indicated. RESULTS: Cancer was detected in biopsy specimens of 40 patients. Of these cancers, 18 originated in the PZ alone and 22 were located both in the TZ and the PZ. No cancers were detected in the TZ alone. Of 99 patients who were proven not to have cancer by the biopsies, 18 were indicated for TURP. Five of these patients (28%) had cancer in the resected tissues. All cancers were clinically organ confined and their Gleason sum scores were 2-5. Cancer-positive chips accounted for less than 10% of all resected specimens. Of the 66 patients with negative biopsies and without indication for TURP, four (6%) were revealed to have an elevation of the serum PSA level during follow up. They were later proven to have cancer by a second biopsy. CONCLUSION: Routine use of TZ biopsy is not warranted for detection of cancer. Transurethral resection of the prostate can detect cancers in patients with negative PZ and TZ biopsies. However, cancers detected by TURP may not always be clinically significant and only four of 66 patients who were not indicated for TURP and received a close follow up were later found to have cancer, although their follow-up period was short. Thus, it still remains to be elucidated whether TURP is necessary for all patients with negative biopsies of the prostate.

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