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M L Blute

Publications and source records attributed to M L Blute.

At least 55 records · Page 3Linked to original sources
PubMed1999

Comparison of clinically nonpalpable prostate-specific antigen-detected (cT1c) versus palpable (cT2) prostate cancers in patients undergoing radical retropubic prostatectomy.

OBJECTIVES: Serum prostate-specific antigen (PSA) testing has led to increased detection of clinically localized prostate cancer. We analyzed the clinical characteristics and outcome of digitally palpable (cT2) and PSA detected (cT1c) prostate cancers. METHODS: We evaluated 4453 patients with clinically localized prostate cancer who underwent radical retropubic prostatectomy (RRP) between 1987 and 1995 at the Mayo Clinic. Overall, 1041 (23.4%), 1076 (24.2%), and 2336 (52.5%) patients had cT1c, cT2a, and cT2b/c disease, respectively. Patients were analyzed with regard to Gleason score, preoperative PSA, pathologic stage, deoxyribonucleic acid (DNA) ploidy, margin status, tumor volume, and adjuvant treatment. Survival outcomes at 5 and 7 years were estimated using the Kaplan-Meier method with respect to the end points of systemic/local clinical progression and clinical and/or PSA progression (greater than 0.2 microg/mL). Multivariate analysis was employed to estimate the relative risk of progression associated with each clinical stage when adjusted for the above factors. RESULTS: Clinical T1c tumors were more likely to be organ confined (76% versus 54%), have a Gleason score less than 7 (75% versus 61%), and be diploid (80% versus 70%) than cT2b/c tumors (P <0.001). Clinical T1c disease closely resembled cT2b/c disease with respect to preoperative PSA. Considering pathologic stage, DNA ploidy, and tumor volume, cT1c tumors were comparable to cT2a lesions. Of the patients with T1c cancers, 96.2% had clinically significant cancer on the basis of pathologic grade and tumor volume. The 5 (and 7 year) systemic/local clinical progression-free and PSA progression-free survivals for cT1c tumors were 97.7+/-0.7% (96.4+/-1.1%) and 82.2+/-1.7% (72.9+/-3.8%), respectively. There was a significant survival advantage at 5 and 7 years regarding both end points for cT1c and cT2a compared with cT2b/c tumors (P <0.001). Multivariate analysis revealed a continued benefit in PSA and systemic/local clinical progression for cT1c tumors compared with cT2b/c tumors adjusting for the above factors. CONCLUSIONS: Clinical T1c tumors are clinically significant cancers. When compared with digitally palpable tumors, progression-free survival rates for cT1c tumors are similar to cT2a lesions, but are significantly better than cT2b/c lesions. This supports continued use of serum PSA to detect potentially curable prostate cancer.

Adult↗
PubMed1999

Mycotic vascular infections of large arteries with Mycobacterium bovis after intravesical bacillus Calmette-Guérin therapy: case report.

Disseminated infection after intravesical bacille Calmette-Guérin instillation for bladder cancer is a rare but potential complication. Vascular infection is an additional serious complication but is seldom reported. We present the first report of a small series of patients with vascular infections after intravesical bacille Calmette-Guérin instillation, and we review the related literature.

Administration, Intravesical↗
PubMed1999

Renal oncocytoma: multifocality, bilateralism, metachronous tumor development and coexistent renal cell carcinoma.

PURPOSE: We analyzed a large series of cases of renal oncocytoma to define the incidence of coexistent renal cell carcinoma, multifocality, bilateralism and metachronous tumor development. MATERIALS AND METHODS: Between 1980 and 1997, 100 men and 38 women with a mean age of 68 years with oncocytoma, were treated surgically at our institution. We analyzed tumor characteristics and reviewed specimens for coexistent renal cell carcinoma. RESULTS: Tumors were discovered incidentally in 58% of the cases. Specimens were obtained from 84 radical and 70 partial nephrectomies. Tumor size ranged from 0.3 to 14.5 cm. (median 3.2). Oncocytoma was unilateral in 131 cases (95%) and bilateral in 7 (5%), while there were multiple oncocytomas in 8 (6%). Mean followup was 41 months (range 0 to 200). The disease specific survival rate was 100% and no patient had metastasis. In 6 patients (4%) metachronous oncocytoma developed during followup. No patient had locally recurrent oncocytoma after partial nephrectomy for a solitary renal oncocytoma. Renal cell carcinoma and oncocytoma were found in 14 patients (10%), including unilateral synchronous disease in 9 and bilateral synchronous disease in 5. CONCLUSIONS: Our data support the benign nature of renal oncocytoma. Multifocality, bilateralism and metachronous tumor develop in approximately 4 to 6% of all cases. Renal cell carcinoma coexisted in 10% of oncocytoma cases.

Adenoma, Oxyphilic↗
PubMed1999

Deoxyribonucleic acid ploidy and serum prostate specific antigen predict outcome following salvage prostatectomy for radiation refractory prostate cancer.

PURPOSE: We assessed clinical and pathological variables for the ability to predict improved outcome following salvage prostatectomy for radiation refractory prostate cancer. We identify factors that might assist in selection of candidates for this procedure. MATERIALS AND METHODS: Between 1966 and 1996, 108 patients (mean age 64.7 years) underwent salvage radical retropubic prostatectomy for radiation refractory prostate cancer. Preoperative serum prostate specific antigen (PSA), available in 70 patients treated since 1987, was less than 4 in 19, 4 to 10 in 31 and greater than 10 ng./ml. in 20. Serum PSA before radiotherapy was available in 37 patients. Serum PSA before radiotherapy and salvage surgery, tumor grade, deoxyribonucleic acid (DNA) ploidy and margin status were analyzed for the ability to predict cancer specific and progression-free survival (local, systemic and PSA 0.2 ng./ml. or greater). Complication rates were compared between early (before 1990) and late (1990 to 1996) salvage prostatectomy groups. RESULTS: Overall cancer specific and progression-free survival at 10 years was 70 and 44%, respectively. The pathological stage was pT2N0 in 39%, pT3-4N0 in 42% and pTxN+ in 19% of cases. DNA ploidy was predominately nondiploid, that is diploid in 25%, tetraploid in 64% and aneuploid in 11% of tumors. Although preoperative serum PSA was not predictive of pathological stage, patients with preoperative PSA less than 10 ng./ml. had better progression-free survival than those with higher levels (p = 0.05). DNA ploidy was the strongest predictor of cancer specific (p = 0.002) and progression-free (p = 0.002) survival. Controlling for grade and PSA using the Cox proportional hazards model, DNA ploidy remained a significant predictor of prostate cancer death (p <0.001) and disease progression (p <0.001). Complication rates improved somewhat in more recently treated patients but incontinence and bladder neck contracture rates remained significant. CONCLUSIONS: DNA ploidy and preoperative serum PSA appear to be the most important predictors of outcome following salvage prostatectomy for radiation refractory prostate cancer. Preoperative consideration of these factors may be helpful in selecting candidates for this procedure.

Aged↗
PubMed1999

Radical retropubic prostatectomy plus orchiectomy versus orchiectomy alone for pTxN+ prostate cancer: a matched comparison.

PURPOSE: Untreated stage pTxN+ prostate cancer is associated with a poor outcome. Monotherapy (surgery, radiation, hormonal therapy) alone is associated with a high progression rate. We evaluate whether radical prostatectomy and pelvic lymphadenectomy plus early adjuvant orchiectomy impart a survival advantage compared to pelvic lymphadenectomy and orchiectomy alone in a matched cohort of patients. MATERIALS AND METHODS: Between 1966 and 1995, 382 and 79 patients with stage pTxN+ prostate cancer underwent pelvic lymphadenectomy and radical prostatectomy plus early adjuvant orchiectomy (within 3 months of prostatectomy), and pelvic lymphadenectomy and orchiectomy only, respectively. We selected 79 matched controls from the prostatectomy plus orchiectomy group for the orchiectomy group. Patients were matched according to the number of positive nodes, clinical grade, clinical stage, age, year of surgery and preoperative prostate specific antigen (after 1987). The Kaplan-Meier method and stratified Cox proportional hazards model were used to estimate overall and cause specific survival for the 2 groups. RESULTS: There was an overall survival advantage at 10 years for the prostatectomy plus orchiectomy (66+/-6%) compared to the orchiectomy (28+/-6%) group (p <0.001, risk ratio 0.36, 95% confidence interval 0.20 to 0.66). There was also an advantage in cause specific survival at 10 years in the prostatectomy plus orchiectomy (79+/-5%) versus the orchiectomy (39+/-7%) group (p <0.001, relative risk 0.28, 95% confidence interval 0.13 to 0.59). After 1987, when matched on preoperative prostate specific antigen, the apparent survival advantage at 5 years with radical prostatectomy was smaller (79+/-8 versus 63+/-9% orchiectomy) and not significant (p = 0.19). CONCLUSIONS: This retrospective study of patients with stage pTxN+ PC suggests that radical prostatectomy with early adjuvant orchiectomy may provide a significant advantage in overall and cause specific survival compared to orchiectomy alone.

Aged↗
PubMed1999

Prospective analysis of intraoperative frozen needle biopsy of solid renal masses in adults.

PURPOSE: We prospectively determined the accuracy of intraoperative needle biopsy of solid renal masses. MATERIALS AND METHODS: A total of 103 patients diagnosed with a solid renal mass and scheduled for surgery were prospectively evaluated. Radical or partial nephrectomy was performed, and biopsy of the surgical specimen was done twice through the tumor using an 18 gauge biopsy gun. Biopsy specimens of 106 tumors were sent for frozen sectioning, stained with hematoxylin and eosin, and reviewed by 2 independent pathologists blinded to each other and whole tissue specimens. Biopsy results were compared to whole tissue specimens. RESULTS: Specimens were obtained from 60 radical and 46 partial nephrectomy cases. Malignant neoplasms were present in 91 cases (86%). Overall, 15 cases (14%) were benign, of which 11 were oncocytomas. If lesions 4 cm. or less only were included in analysis, the incidence of benign lesions increased to 22%. Overall accuracy of the 2 pathologists was 76 and 80%. Nondiagnostic rates were 11 and 17%. Both observers incorrectly diagnosed 4 malignant lesions (5%) as benign, and incorrectly diagnosed 3 and 5 benign lesions (21 and 36%), respectively, as malignant. Analysis of values for both observers yielded a sensitivity of 77 and 84%, specificity 60 and 73%, positive predictive value 94 and 96%, and negative predictive value 69 and 73%. CONCLUSIONS: Overall frozen needle biopsy was accurate in more than 75% of cases and showed an excellent positive predictive value for carcinoma of more than 94%. Unfortunately, there was a large degree of inaccuracy for benign lesions and we do not recommend the routine use of intraoperative frozen needle biopsy to guide surgical decision making.

Adult↗
PubMed1999

Cell proliferation in prostate cancer patients with lymph node metastasis: a marker for progression.

The biological aggressiveness of lymph node-positive prostate cancer is closely linked to cancer volume in nodal metastases. We evaluated MIB-1 (Ki-67) labeling index and bcl-2 expression in primary cancer and matched nodal metastases from 138 node-positive patients treated with radical prostatectomy and bilateral pelvic lymphadenectomy between 1987 and 1992 at the Mayo Clinic. One hundred twenty-eight patients (93%) received androgen deprivation therapy within 90 days after radical prostatectomy. Mean patient age was 66 years (range, 51-78). The median follow-up was 6.7 years (range, 0.03-11). MIB-1 (Ki-67) labeling index was determined by digital image analysis, and nodal cancer volume was determined by the grid method. Systemic progression, defined as the presence of distant metastasis documented by biopsy or radiographic examination, was used as an outcome end point in the Cox proportional hazard models. MIB-1 labeling index in nodal metastases was predictive of systemic progression-free survival (P = 0.001). The 8-year systemic progression-free survival was 100% for those with MIB-1 labeling index <3.5% compared with 78% for those with MIB-1 labeling index > or =7.8%. MIB-1 labeling index correlated with Gleason score, DNA ploidy, and nodal cancer volume (P<0.001, 0.04, and <0.001, respectively). After controlling for nodal cancer volume, MIB-1 labeling index remained significant in predicting systemic progression-free survival (P = 0.047). bcl-2 expression in the primary cancer and lymph node metastasis was associated with systemic progression-free survival in univariate analysis (P = 0.027 and 0.048, respectively) but was not significant after adjusting for nodal cancer volume (P = 0.52 and 0.17, respectively). Our data indicate that assessment of cell proliferation in nodal metastasis is predictive of clinical outcome in prostate cancer patients with regional lymph node metastasis.

Aged↗
PubMed1999

Comparison of screening methods in the detection of bladder cancer.

PURPOSE: We prospectively evaluate and compare the sensitivity and specificity of urine cytology, BTA stat, NMP22, fibrin/fibrinogen degradation products (FDP), telomerase, chemiluminescent hemoglobin and hemoglobin dipstick to detect bladder cancer. MATERIALS AND METHODS: Single voided specimens were obtained from 57 patients with bladder cancer, and 139 without evidence of bladder malignancy on cystoscopy or a negative biopsy of indeterminate lesions. A cytology report was available for 125 patients and interpreted independently. BTA stat, NMP22 and FDP were analyzed according to manufacturer specifications. The telomerase assay was performed on cells collected from urine by centrifugation in preparation for polymerase chain reaction based amplification using the telomeric repeat amplification protocol assay. The chemiluminescent screening assay for hemoglobin in urine uses the pseudoperoxidase activity of hemoglobin on hydrogen peroxide and subsequent oxidation of 7-dimethylaminonaphthalene-1,2-dicarbonic acid hydrazide to generate chemiluminescence emission. Hemoglobin dipstick was interpreted as positive if the hemoglobin content in the urine was trace or greater. RESULTS: Overall sensitivity with urine cytology, BTA stat, NMP22, FDP, telomerase, chemiluminescent hemoglobin and the hemoglobin dipstick was 44, 74, 53, 52, 70, 67 and 47%, respectively. Specificity with cytology, telomerase and FDP was high (95, 99 and 91%, respectively) but BTA stat, NMP22 (optimized), chemiluminescent hemoglobin (optimized) and the hemoglobin dipstick demonstrated lower specificity of 73, 60, 63 and 84%, respectively. Stepwise logistic regression analysis revealed that for all tumors, and within each tumor grade and stage telomerase had the strongest association with bladder cancer among all tests (69% overall concordance). Telomerase was also positive in 91% of the patients (10 of 11) with carcinoma in situ. CONCLUSIONS: Urinary telomerase had the highest combination of sensitivity and specificity (70 and 99%, respectively) for bladder cancer screening in these patients. It was the strongest predictor with superior accuracy in patients with grade 1 and noninvasive tumors (pTa), and extremely useful in patients with carcinoma in situ. Telomerase appears to be promising and outperformed cytology, BTA stat, NMP22, FDP, chemiluminescent hemoglobin and hemoglobin dipstick in the prediction of bladder cancer.

Adult↗
PubMed1998

Pathologic classification of prostate carcinoma: the impact of margin status.

BACKGROUND: A proposed pathologic (pTNM) classification system for prostate carcinoma was analyzed for its impact on survival outcome in the prostate specific antigen (PSA) era. The impact of margin status on the survival outcome of patients with otherwise organ-confined disease (i.e., without extraprostatic extension or seminal vesicle involvement) was assessed. METHODS: Among 5467 patients, the original pathologic classification was T2 in 2094 patients; those with evidence of positive margins, extraprostatic extension, or seminal vesicle involvement were initially classified as having pT3 disease (2920 patients) or pT4 residual disease (211 patients). According to the proposed pTNM system, 1512 patients for whom margin status was considered independent of T classification were reclassified. RESULTS: After reclassification, 803 specimens had been down-classified to pT2, resulting in 2932 (54%) with pT2N0 organ-confined disease and a margin positivity rate of 27%; originally, only 38% of patients had been classified as pT2N0. When the old and new classifications were compared, 5-year progression free survival to the combined endpoint of clinical and/or PSA progression (< or = 0.2 ng/mL) was 86% versus 84% and 70% versus 67% for disease classified as pT2N0 and pT3N0, respectively. Multivariate analysis assessed the effect of margin status on 2334 pT2N0 patients (classified according to the proposed pTNM system) who did not receive adjuvant therapy; adjustments were made for Gleason grade, preoperative PSA, and DNA ploidy. In this analysis, the relative risk (with 95% confidence interval) associated with positive margins was 1.65 (1.24-2.18); this was significant for the combined endpoint of clinical/PSA progression. The 5-year survival, free of clinical/PSA progression, was 86% for those without versus 75% for those with positive margins. CONCLUSIONS: This analysis supports the adoption of the proposed pTNM system, which will allow for uniform reporting of pathologic data on prostate carcinoma. For patients with organ-confined disease, positive margins are associated with higher rates of PSA progression. Accordingly, patients should be stratified based on margin positivity in addition to pT classification.

Humans↗
PubMed1998

Transurethral thermotherapy using the Prostatron device.

This paper reviews the available data on low- and high-energy transurethral microwave thermotherapy (TUMT) in the treatment of patients with benign prostatic hyperplasia (BPH). Furthermore, it provides a perspective for this minimally invasive treatment modality in the selection of patients and in future developments. In evaluations of the two software modalities, several clinical studies have proved them to be effective. Whereas the lower-energy software seems to be the better choice for treatment of patients with lower urinary tract symptoms who have a lower grade of outlet obstruction and a smaller prostate, the higher-energy mode should be used to deobstruct and can be used in patients with larger prostates and moderate to severe outlet obstruction. Although baseline parameters can be used to predict the response to treatment in the higher-energy software mode, the total amount of energy remains very important for the final outcome, and future efforts should be encouraged to quantify prostate vascularization and histology in relation to transurethral microwave heating. Furthermore, future developments should focus on shorter treatment times and minimization of morbidity.

Diathermy↗
PubMed1998

1997 American Urological Association Gallup survey: Changes in diagnosis and management of prostate cancer and benign prostatic hyperplasia, and other practice trends from 1994 to 1997.

PURPOSE: The American Urological Association first commissioned the Gallup Organization to conduct a study to assess urologist practice patterns in 1992. We present the results of the 1997 survey, the sixth consecutive Gallup survey performed for the Association. MATERIALS AND METHODS: A random sample of 502 American urologists who had completed urological residency and practiced at least 20 hours weekly in 1996 was interviewed by telephone in February and March 1997. RESULTS: Emerging trends showed significant changes since 1994 in how urologists diagnosed and treated prostate cancer. The survey revealed a significant change in the tests routinely ordered to stage newly diagnosed prostate cancer and for diagnostic evaluation of patients with benign prostatic hyperplasia. CONCLUSIONS: Urologists are becoming more cost conscious and effective in ordering pretreatment testing. Urologists are becoming more oriented toward medical treatment for the management of benign prostatic hyperplasia, and less laser surgery is being performed.

Adult↗
PubMed1998

Comparison of studer ileal neobladder and ileal conduit urinary diversion with respect to perioperative outcome and late complications.

PURPOSE: We compare the perioperative and long-term morbidity of a cohort of patients who had undergone Studer ileal neobladder urinary diversion with that of a similar cohort who had undergone ileal conduit urinary diversion during the same interval and by the same surgeons. MATERIALS AND METHODS: Between 1990 and 1996 we performed Studer ileal neobladder urinary diversion in 62 men and 4 women, and ileal conduit urinary diversion in 66 men. Mean age of the neobladder and conduit patients was 62 and 69 years, and mean followup was 17 and 20 months, respectively. RESULTS: Of 66 neobladder cases (18%) 12 had a total of 16 perioperative complications and a 5% reoperation rate, whereas 12 of 66 conduit cases (18%) had a total of 17 perioperative complications and a 6% reoperation rate. Mean hospital stay was 13 days for each group. Of the neobladder cases 14 (21%) had 14 late complications and an 11% reoperation rate, whereas 8 conduit cases (12%) had 9 late complications and an 8% reoperation rate. CONCLUSIONS: The Studer ileal neobladder urinary diversion is a safe procedure with perioperative and long-term morbidity comparable to ileal conduit diversion at our institution.

Adult↗
PubMed1998

Long-term outcome in patients with pTxN+ adenocarcinoma of prostate treated with radical prostatectomy and early androgen ablation.

PURPOSE: We assessed retrospectively the outcome after bilateral pelvic lymphadenectomy and radical prostatectomy for pathological pTxN+ adenocarcinoma of the prostate when treated with or without adjuvant androgen ablation therapy. MATERIALS AND METHODS: A total of 790 men treated with radical prostatectomy for prostatic adenocarcinoma were found to have pTxN+ disease and treated further with or without androgen ablation therapy. Mean patient age was 64 years (range 40 to 79). Mean followup was 6.5 years, (range up to 25). Clinical stages were T2 or less in 60% of the cases, T3 in 38% and N+ in 2%. Gleason scores were 6 or less in 31% and 7 or greater in 69%. Deoxyribonucleic acid ploidy was diploid in 43%, tetraploid in 39% and aneuploid in 18%. Of the patients 96 (12%) received no androgen ablation therapy, with the remainder getting androgen ablation therapy within 90 days of radical prostatectomy. RESULTS: Of the patients 186 (24%) died, with 109 (14%) dying of prostatic anedocarcinoma. Overall (and cause specific) survival probabilities at 5, 10 and 15 years were 87 (91), 69 (79) and 39% (60%), respectively. Patients with diploid tumors had better cause specific survival than those with nondiploid tumors (p = 0.009). Patients with diploid tumors were less likely to have progression biochemically, locally or systemically than those with nondiploid tumors (p = 0.038). Androgen ablation therapy had no effect on cause specific survival in nondiploid patients. Diploid patients treated with androgen ablation therapy for up to 10 years had no improvement in disease specific survival compared to those with no androgen ablation therapy. However, cancer death was significantly reduced after 10 years (p <0.002). The local control rate of pTxN+ cases that receive radical prostatectomy and androgen ablation therapy at 15 years is virtually identical to that of stage pT2c cases at our institution (79 +/- 3.0 versus 80% +/- 3.5%, respectively). There were no deaths secondary to radical prostatectomy, and complications were within the experience of that seen in patients with localized disease. CONCLUSIONS: Radical prostatectomy with androgen ablation therapy is a viable option for patients with pTxN+ disease, particularly in view of excellent local control rates and low morbidity. Patients with diploid tumors have a more favorable outcome than those with nondiploid tumors when treated with androgen ablation therapy.

Adenocarcinoma↗
PubMed1998

Influence of prostate-specific antigen testing on the spectrum of patients with prostate cancer undergoing radical prostatectomy at a large referral practice.

OBJECTIVE: To analyze trends in the clinical stage and pathologic outcome of patients with prostate cancer who underwent radical prostatectomy at a large referral practice during the prostate-specific antigen (PSA) testing era. MATERIAL AND METHODS: Between January 1987 and June 1995, 5,568 patients with prostate cancer (4,774 with clinically localized disease of stage T2c or less) underwent pelvic lymphadenectomy and radical retropubic prostatectomy at our institution. Patient age, preoperative serum PSA level, clinical stage, pathologic stage, Gleason score, and tumor ploidy were assessed. Outcome was based on clinical and PSA (increases in PSA level of 0.2 ng/mL or more) progression-free survival. RESULTS: Patient age (65 to 63 years old; P<0.001) and serum PSA level (median, 8.4 to 6.8 ng/mL; P<0.001) decreased during the study period. The percentage of patients with clinical stage T1c prostate cancer increased from 2.1% in 1987 to 36.4% in 1995 (P<0.001), and clinical stage T3 cancer decreased from 25.3% to 6.5% (P<0.001). Nondiploid tumors decreased from 38.3% to 24.6% (P<0.001), and the proportion of patients with pathologically organ-confined disease increased from 54.9% to 74.3% (P<0.001). More cT1c than cT2 tumors were diploid (80% versus 72%; P<0.001), had a Gleason score of 7 or less (75% versus 65%; P<0.001), and were confined to the prostate (75% versus 57%; P<0.001). Five-year progression-free survival was 85% and 76% for patients with clinical stage T1c and T2, respectively (P<0.001). CONCLUSION: Since the advent of PSA testing, patients referred to our institution for radical prostatectomy have shown a significant migration to lower-stage, less-nondiploid, more often organ-confined prostate cancer at the time of initial assessment. Cancer-free survival associated with PSA-detected cancer (cT1c) is superior to that with palpable tumors (cT2). Whether these trends translate into improved long-term cancer-specific survival remains to be confirmed with longer follow-up.

Adult↗
PubMed1998

A high-efficiency microwave thermoablation system for the treatment of benign prostatic hyperplasia: results of a randomized, sham-controlled, prospective, double-blind, multicenter clinical trial.

OBJECTIVES: To determine the effectiveness, safety, and impact on patient quality of life (QOL) of a novel transurethral microwave thermoablation system for the treatment of benign prostatic hyperplasia (BPH). METHODS: A total of 169 patients with BPH were randomized to undergo a 1-hour microwave (n = 125) or sham (n = 44) procedure using the Urologix Targis thermoablation system on an outpatient basis, without general or regional anesthesia. Symptoms, flow rates, and QOL scores were determined before the study procedure and periodically thereafter up to 6 months. RESULTS: Mean American Urological Association (AUA) score in the microwave group diminished 50% (P <0.0005) by the 6-month evaluation (10.5, 95% confidence interval [CI] 9.2 to 11.8) compared with baseline values (20.8, 95% CI 19.8 to 21.9). The sham group also exhibited lower postprocedural AUA scores; however, the magnitude of the postprocedural decline in AUA score in the microwave group was significantly greater (P <0.01) than that in the sham group. Half the microwave group had an AUA score of less than 9 by 6 months, and the decrease in symptoms was similar among patients with initially moderate versus initially severe symptoms. Mean peak urinary flow rate (Qmax) in the microwave group increased 51% (P <0.0005) by 6 months to 11.8 mL/s (95% CI 10.7 to 13.0) versus a pretreatment value of 7.8 mL/s (95% CI 7.4 to 8.2). The magnitude of the postprocedural increase in Qmax was significantly greater in the microwave than the sham group (P <0.05). In nearly half the microwave group (47%), Qmax increased 50% or more by 6 months compared with 24% of the sham group. Microwave treatment resulted in a significantly greater (P <0.05) positive impact on patient QOL than did the sham procedure. By 6 months, the QOL score in microwave-treated patients (2.2, 95% CI 1.9 to 2.4) averaged 48% lower (P <0.0005) than that at baseline (4.2, 95% CI 4.0 to 4.4). Significantly greater durability of treatment effects was also evident with microwave than with sham treatment, as judged by the higher proportion of microwave-treated patients (98.4%) requiring no further treatment during the 6-month study period versus 83.3% of sham control patients (P <0.0005). Microwave treatment was well tolerated, and complications were generally minor, readily manageable, and transitory. CONCLUSIONS: The microwave thermoablation system proved to be an effective and safe treatment modality for BPH, with a positive impact on patient QOL.

Aged↗
PubMed1998

Contrasting heating patterns and efficiency of the Prostatron and Targis microwave antennae for thermal treatment of benign prostatic hyperplasia.

OBJECTIVES: To determine the design and performance characteristics of two microwave antennae for use in thermal treatment of benign prostatic hyperplasia. METHODS: Prostatron and Targis antennae were subjected to detailed physical examination and measurement. The heating patterns generated by these two types of antennae were characterized in detail using tissue-equivalent phantoms. Measurements of return loss as a function of frequency were conducted to evaluate the capacity of the antennae for impedance matching. Percent reflected power was calculated from the return loss results to provide a relative measure of potential for efficient delivery of thermal energy. RESULTS: The Prostatron antenna was found to be a monopole design consisting of a coaxial cable with a 3.3-cm length of inner conductor exposed at the tip. The Targis antenna was observed to be a dipole design with a 2.8-cm helical coil attached through a ground connection and a tap point to a coaxial cable. The heating pattern of the Targis antenna was symmetric; that of the Prostatron was asymmetric with substantial back heating along the catheter axis in the direction of the microwave power source. The mean extension of the 30 degrees C isotherm in the direction of the power source with the Prostatron antenna (71.5 mm; 95% confidence interval [CI], 63.4 to 79.6 mm) was 55% greater (P < 0.0005) than that with the Targis antenna (46.0 mm; 95% CI, 38.2 to 53.8 mm). Return loss with the Targis antenna declined sharply to a relative minimum value of -32.9 dB (95% CI, -73.8 to 8.0 dB) at 915 MHz, providing evidence of this antenna's capacity for impedance matching; little change was observed with the Prostatron in return loss over a frequency range 100 MHz above and below this antenna's standard operating frequency of 1296 MHz. The mean reflected power of the Targis antenna (0.4%; 95% CI, 0.0% to 1.4%) was lower by more than 20-fold (P = 0.036) than that of the Prostatron antenna (11.0%; 95% CI, 3.4% to 18.7%); thus, the potential for efficient operation was greater with the Targis than the Prostatron antenna. CONCLUSIONS: The Targis microwave antenna was found to provide a more targeted heating pattern and have a capacity for more efficient thermal energy delivery than the Prostatron antenna. These differences observed in vitro could potentially translate into clinical advantages in vivo, such as improved tolerability of microwave treatment, reduced risk of complications, greater thermoablative efficacy, and scalability.

Diathermy↗