Electron beam computerized tomography assessment of in vivo single kidney glomerular filtration rate and tubular dynamics during chronic partial unilateral ureteral obstruction in the pig.

PURPOSE: The assessment of hydronephrosis due to chronic partial ureteral obstruction is controversial. We determined whether a new radiographic technique for assessing kidney function, electron beam computerized tomography (CT), can detect altered renal physiology due to chronic partial ureteral obstruction. We also compared and contrasted electron beam CT with standard well tempered diuretic mercaptoacetyltriglycine (MAG-3) urography. MATERIALS ANDS METHODS: Six pigs underwent creation of unilateral partial ureteral occlusion or sham operation. Three weeks after surgery diuretic enhanced MAG-3 renal scan was done and 48 hours later contrast enhanced electron beam CT was performed. RESULTS: Mean differential function plus or minus standard error of mean of the obstructed kidney was 5.6% +/- 2.4% on MAG-3 renography. In contrast, electron beam CT revealed significantly preserved mean renal function at 24.5% +/- 2.7% (p <0.01). Electron beam CT analysis of tubular function revealed persistent glomerular filtration and filtrate flow through the proximal tubules and loop of Henle with a selective decrease in distal tubular flow, which were findings suggestive of proximal tubular sparing that were not demonstrated by nuclear renography. CONCLUSIONS: Renal function on MAG-3 renography is primarily determined by measuring kidney perfusion and tubular secretion of the isotope. In contrast, electron beam CT determines renal function via quantifying the in vivo single kidney glomerular filtration rate and by assessing renal tubular function. This study documents that electron beam CT of differential renal function is significantly different from that of MAG-3 renography. To our knowledge which of these 2 radiographic studies is most clinically applicable is unknown to date.

Transurethral hot-water balloon thermoablation for benign prostatic hyperplasia: patient tolerance and pathologic findings.

OBJECTIVES: To determine the patient tolerance and thermal ablation pattern in human prostatic tissue after treatment with a hot water, catheter-based system. METHODS: Twenty-seven men scheduled for surgery for symptomatic benign prostatic hyperplasia or adenocarcinoma of the prostate underwent water-induced thermotherapy. The patients were randomly assigned to one of four treatment groups. Lidocaine gel was the sole means of pain control. The patients and an observer recorded patient discomfort during therapy. A Foley catheter was left in place until surgery (n = 13) or successful voiding (n = 14). Prostates were subsequently enucleated or removed, whole mounted, and examined. RESULTS: Patients reported mild treatment discomfort, the level of which did not correlate with the extent of necrosis, balloon diameter, or water temperature (all P >0. 05). Distal penile burning was the most commonly reported discomfort. All 14 patients successfully voided within 12 days of treatment. Prostates were enucleated (n = 24) or removed (n = 3) at a mean of 27 days (range 4 to 120) after thermotherapy, except for a single adenectomy 17 months after therapy. Pathologic findings included periurethral hemorrhagic necrosis, with focal or extensive urothelial denudation and mild inflammation. The mean maximal depth of necrosis from the urethral lumen was 7, 9, 10.33, and 11 mm in groups 1, 2, 3, and 4, respectively. The extent of necrosis was similar in all groups (P = 0.11), regardless of the water temperature; conversely, the balloon diameter correlated with the depth of necrosis (P = 0.024). CONCLUSIONS: This system of tissue ablation appears to be well tolerated, and it produced consistent pathologic results.

Does transurethral microwave thermotherapy have a different effect on prostate cancer than on benign or hyperplastic tissue?

OBJECTIVES: Transurethral microwave thermotherapy is useful for the treatment of benign prostatic hyperplasia, but its effect on cancer is not documented. We analyzed the pathologic changes occurring after microwave thermotherapy in whole mount radical prostatectomy specimens from patients with cancer. METHODS: Nine patients scheduled for radical prostatectomy for clinically localized prostate cancer were treated with transurethral microwave thermotherapy (Urologix Targis System). Patients ranged in age from 64 to 72 years (mean 68). Seven patients underwent prostatectomy 4 to 90 hours after thermotherapy, and 2 other patients underwent prostatectomy 12 months after thermotherapy. Whole mount totally embedded prostates were mapped for necrosis and cancer, and the volume of each was measured by the grid method. RESULTS: Pathologic stages were T2a (n = 4), T2b (n = 4), and T3b (n = 1). The prostates from patients who underwent radical prostatectomy within 4 to 90 hours of thermotherapy had a mean prostate weight of 47.4 g (range 19.5 to 70.3). Each consistently showed hemorrhagic necrosis and tissue devitalization without significant inflammation. Necrosis involved contiguous areas of benign epithelium, stroma, and cancer without skip areas. The mean volume of necrosis was 8.8 cc (range 1.4 to 17.8), and the mean percentage of the prostate involved by necrosis was 22% (range 3% to 39%). The necrosis was symmetric around the urethra in 6 of 7 cases. Urethral dilation was observed in 3 patients, and the mean maximum radial distance of necrotic tissue was 1.4 cm (range 0.6 to 1.8). Necrotic change was noted in 80% to 100% of the volume of cancer in 4 cases, 40% to 60% in 2 cases, and 5% in 1 case. The prostates from the 2 patients who underwent radical prostatectomy 12 months after thermotherapy had a mean weight of 88 g (55 and 121 g, respectively). Each showed periurethral fibrosis, nonspecific chronic inflammation, and squamous metaplasia of the urothelium. The mean volume of necrosis remaining was 0.2 cc. The mean percentage of the prostate involved by necrosis 1 year after thermotherapy was less than 1%. There was some reabsorption of dead tissue. The mean maximum radial distance of the necrotic tissue was 0.4 cm (0.2 and 0.7 cm, respectively). The prostatic urethra had viable and partially denuded urothelium in all cases. CONCLUSIONS: Microwave thermotherapy is clinically useful for ablation of benign prostate and cancer contiguous to the urethra, resulting in hemorrhagic necrosis with minimal damage to the urethra. There was no apparent differential morphologic sensitivity of benign prostatic tissue, hyperplastic tissue, or cancer to thermotherapy.

Clinically unsuspected and undetected (clinical stage t0) prostate cancer diagnosed on random needle biopsy.

OBJECTIVES: To describe the findings in 4 patients who underwent radical prostatectomy for clinically undetected and unsuspected prostate cancer detected on random needle biopsy. METHODS: We reviewed the Mayo Clinic Radical Prostatectomy Prostate Cancer Database of 5793 prostatectomies from 1987 to 1997, and identified 4 patients who had prostate cancer detected on random needle biopsy of the prostate with serum prostate-specific antigen (PSA) less than 4 ng/mL and normal digital rectal examination. Each had requested biopsy despite the absence of clinical suspicion of cancer; 3 had normal transrectal ultrasound, and the fourth had a benign hypoechoic lesion contralateral to the cancer. RESULTS: Mean patient age at diagnosis was 65.5 years (range 61 to 67). Mean PSA was 2.4 ng/mL (range 2 to 2.9). Mean tumor volume was 3 cc (range 0.04 to 11.2). Mean Gleason grade at prostatectomy was 5.75 (range 5 to 7). Prostate cancer was Stage T2a in 1 patient (25%), T2c in 2 (50%), and T3a (25%) in 1. Three tumors were DNA diploid, and one was aneuploid. All patients were alive without evidence of cancer at a mean follow-up of 43 months (range 25 to 53) with undetectable serum PSA concentration. CONCLUSIONS: Our findings indicate that clinically unsuspected and undetected (clinical Stage T0) prostate cancer may be clinically significant. Patient insistence on biopsy reflects increasing concern among the public about prostate cancer. Current clinical thresholds for biopsy detection will fail for some patients with clinically significant prostate cancer.

Prostatic central zone volume, lower urinary tract symptom severity and peak urinary flow rates in community dwelling men.

PURPOSE: Previous studies have suggested that central zone prostatic volume may be more strongly correlated with lower urinary tract symptom severity and peak urinary flow rates than total prostatic volume. We determine whether prostatic central zone volume and central zone index volume correlate better with these measures than total prostate volume in an age stratified, community based random sample of healthy white men. MATERIALS AND METHODS: A cohort of 474 men were randomly selected from the 2,115 community dwelling men, 40 to 79 years old, who participated in the Olmsted County study of urinary symptoms and health status among men. All men had undergone transrectal ultrasound of the prostate. The total prostate and hypoechoic central zone volumes were caliper measured by 1 operator on static ultrasounds from baseline. Volumes were calculated with the prolate ellipsoid formula. The operator was blinded to clinical information and outcome. The associations between total prostate volume and central zone index (central zone volume/total volume), and American Urological Association (AUA) symptom index and peak urinary flow rates, respectively, were quantified with the Spearman rank correlation coefficient and least squares regression models. RESULTS: There was a moderately strong correlation between patient age and central zone volume (rs 0.54, p <0.001), total prostate volume (rs 0.45, p <0.001) and central zone index (rs 0.38, p <0.001). The AUA symptom index and peak flow rates correlated less strongly with central zone volume (rs 0.17, p = 0.001 and rs -0.20, p <0.001, respectively) and total volume (rs 0.16, p <0.001 and rs -0.16, p <0.001, respectively). Central zone index weakly correlated with AUA symptom index (rs 0.08, p = 0.103) and peak urinary flow rate (rs -0.08, p = 0.0823). In regression models predicting AUA symptom index and peak flow rates central zone volume added little information after accounting for age and total prostatic volume in predicting AUA symptom index (p = 0.55) and peak flow rate (p = 0.84). CONCLUSIONS: Central zone volume measured from static images optimized for total prostate volume no more closely correlated with lower urinary tract symptom severity or peak urinary flow rates than total prostate volume. Thus, the potentially greater imprecision in measuring central zone volume may not be offset by gains in strength of association with lower urinary tract symptom severity or peak urinary flow rates.

Cystic renal cell carcinoma is cured by resection: a study of 24 cases with long-term followup.

PURPOSE: The true incidence and biological behavior of cystic renal cell carcinoma are not known. To our knowledge we present the largest series of patients with cystic renal cell carcinoma with long-term followup. MATERIALS AND METHODS: We reviewed the Mayo Clinic surgical pathology files of renal cell cancer cases with a cystic component resected from 1969 to 1997, and arbitrarily chose 75% tumor involvement by cysts as a cutoff for inclusion in the study. RESULTS: We identified 24 cases of clear cell renal cell carcinoma with 75% or greater involvement by cysts comprising 0.79% of 3,047 renal cell cancer cases resected at our institution between 1969 and 1997. Mean patient age was 62.7 years (range 40 to 83). A total of 11 patients (46%) underwent radical nephrectomy, 4 (17%) simple nephrectomy, 3 (12%) partial nephrectomy and 6 (25%) tumor enucleation. Mean tumor involvement by cysts was 84% (range 75 to 95) and in 11 cases (46%) involvement was 90% or greater. Cancer stage was T1 in 20 patients (83%), T2 in 1 (4.4%) and T3a in 4 (12.5%). Cancers were diploid in all but 1 case. Mean followup was 77.6 months (range 8 to 428, median 51). A total of 22 patients (92%) had no evidence of cancer and 2 died of intercurrent disease. CONCLUSIONS: Our results indicate that cystic renal cell carcinoma is uncommon and usually cured by resection, regardless of size, stage or number of cysts. These patients may benefit from nephron sparing surgery, such as partial nephrectomy.

Cancer volume of lymph node metastasis predicts progression in prostate cancer.

Clinical outcome is variable in prostate cancer patients with regional lymph node metastasis. We studied 269 patients who had regional lymph node metastasis at the time of radical retropubic prostatectomy and bilateral pelvic lymphadenectomy at the Mayo Clinic between January 1987 and December 1992. Two hundred fifty-three (94%) patients received androgen deprivation therapy within 90 days of radical prostatectomy. Patients ranged in age from 47 to 79 years (median, 67 years). Median follow-up was 6.1 years (range, 0.3-10.5 years). Nodal cancer volume (size) was measured by the grid-counting method. Cox proportional hazards models were used to determine the impact of numerous clinical and pathologic findings on systemic progression-free survival. Systemic progression was defined as the presence of distant metastasis documented by biopsies or radiographic examinations (abdominal computerized tomography, plain radiographs, or bone scan). Five-year progression-free survival was 90%. In predicting systemic progression using Cox multivariate analysis, only nodal cancer volume added significantly to the model containing the primary cancer variables (Gleason score, cancer volume, and DNA ploidy). The relative hazard rate for a doubling in nodal cancer volume was 1.6 (95% confidence interval, 1.3 to 2.0; p < 0.0001). Spearman rank analysis showed a correlation between nodal cancer volume and Gleason score of the primary cancer, the number of positive nodes, the aggregate length of metastases, and the largest nodal cancer diameter (correlation efficient = 0.37, 0.63, 0.96, and 0.95, respectively). Our data indicate that nodal cancer volume was the most significant nodal determinant of progression to distant metastasis in lymph node-positive prostate cancer patients. We recommend that the diameter of the largest metastasis be evaluated in patients with metastases, because this is a more powerful predictor of patient outcome than current methods, which recommend mere counting of the number of positive nodes.

Intestinal metaplasia is not a strong risk factor for bladder cancer: study of 53 cases with long-term follow-up.

OBJECTIVES: Intestinal metaplasia often coexists with adenocarcinoma of the urinary bladder, suggesting to some investigators that it is premalignant. However, the natural history and long-term outcome of intestinal metaplasia in isolation are unknown. We report 53 cases of intestinal metaplasia of the urinary bladder followed for more than 10 years. METHODS: We reviewed the Mayo Clinic surgical pathology files between 1926 and 1996 and all patients with exstrophic bladder recorded in the files of the Hospital for Sick Children (Toronto, Ontario, Canada) and Dallas Children's Hospital (Dallas, Texas) between 1953 and 1987, and identified all patients with intestinal metaplasia of the bladder. RESULTS: A total of 53 cases were identified from both series, and none of the patients developed adenocarcinoma of the bladder. The Mayo Clinic series consisted of 24 patients. Nineteen of the 24 (79.1%) were alive without evidence of cancer (median follow-up 14 years, range 0.9 to 53), and 5 patients died of intercurrent disease (at 0.9, 4, 8, 11, and 53 years after diagnosis) without evidence of bladder cancer. The Dallas Children's Hospital and the Hospital for Sick Children series consisted of 29 patients. Twenty-seven of the 29 (93.1%) were alive without evidence of cancer (median follow-up 13 years, range 3 to 23.9). Two patients died of trauma (at 10.9 and 12 years after diagnosis) and at autopsy had no evidence of bladder cancer. CONCLUSIONS: Intestinal metaplasia of the urinary bladder is not a strong risk factor for adenocarcinoma or urothelial cancer.