The role of cryosurgery of the prostate for nonsurgical candidates.

INTRODUCTION: Technological advancements have reduced the morbidity associated with cryosurgery, leading to an increased interest in this modality for the treatment of organ-confined prostate cancer. In this study, we critically examine the current role of cryoablation of the prostate to better understand how to counsel patients regarding this treatment option. METHODS: A database was compiled over a 3-year period (2008-2011) of 30 patients who underwent cryoablation for organ-confined prostate cancer. Indications for cryosurgery included primary treatment, focal treatment (institutional review board-approved prospective study), and salvage cryotherapy for radiation failure. The primary outcomes were biochemical response via prostate-specific antigen (PSA) measurement and morbidity associated with cryoablation. Cryotherapy failure was defined as an increasing postcryotherapy PSA level ≥ 2 ng/mL above the post-treatment nadir, a positive prostate biopsy, or radiographic evidence of metastatic disease. RESULTS: Of the 30 patients who underwent cryoablation from 2008 to 2011, 26 patients had complete follow-up data for analysis. Of these patients, 17 (65.38%) had total gland cryotherapy, 5 (19.23%) had salvage cryotherapy for radiation failure, and 4 (15.38%) had focal cryotherapy. The mean patient age was 68 years (54-89); median preoperative PSA was 5.5 ng/mL (1.7-15.9); median prostate volume was 35 mL (15-54); mean Gleason score was 7; and the median PSA at study conclusion was 0.7 (0.02-3.4) ng/mL. Of the 17 patients who had total prostate cryotherapy, 11 (64.7%) had significant factors precluding primary treatment by a surgical and/or radiation approach, including neurological disorders (2), morbid obesity (1), rectal cancer treated with radiation (1), kidney/pancreas transplant (2), ileoanal pouch secondary to inflammatory bowel disease (IBD) (1), renal failure (1), and age (3). There were no intra- or postoperative complications. After a median follow-up of 18 months (1-40), none of the patients with multiple comorbidities had biochemical failures. Two patients from the salvage group experienced treatment failure requiring androgen deprivation therapy. CONCLUSIONS: This critical analysis of a single-surgeon experience at a large academic prostate cancer program revealed that the contemporary role of cryosurgery is, in select patients with comorbidities, preventing surgical and/or radiation therapy. Additionally, cryosurgery has a role in treating radiation failures. Further studies are necessary to investigate focal cryotherapy as an option for primary treatment, but our preliminary results are promising, without any biochemical failures in our focal therapy cohort.

Prostate tissue characterization/classification in 144 patient population using wavelet and higher order spectra features from transrectal ultrasound images.

In this work, we have proposed an on-line computer-aided diagnostic system called "UroImage" that classifies a Transrectal Ultrasound (TRUS) image into cancerous or non-cancerous with the help of non-linear Higher Order Spectra (HOS) features and Discrete Wavelet Transform (DWT) coefficients. The UroImage system consists of an on-line system where five significant features (one DWT-based feature and four HOS-based features) are extracted from the test image. These on-line features are transformed by the classifier parameters obtained using the training dataset to determine the class. We trained and tested six classifiers. The dataset used for evaluation had 144 TRUS images which were split into training and testing sets. Three-fold and ten-fold cross-validation protocols were adopted for training and estimating the accuracy of the classifiers. The ground truth used for training was obtained using the biopsy results. Among the six classifiers, using 10-fold cross-validation technique, Support Vector Machine and Fuzzy Sugeno classifiers presented the best classification accuracy of 97.9% with equally high values for sensitivity, specificity and positive predictive value. Our proposed automated system, which achieved more than 95% values for all the performance measures, can be an adjunct tool to provide an initial diagnosis for the identification of patients with prostate cancer. The technique, however, is limited by the limitations of 2D ultrasound guided biopsy, and we intend to improve our technique by using 3D TRUS images in the future.

Histopathologic changes after bipolar resection of the prostate: depth of penetration of bipolar thermal injury.

BACKGROUND AND PURPOSE: While the power needed to initiate bipolar vaporization is higher than conventional monopolar resection, the energy needed to maintain bipolar vaporization is significantly lower and may result in less thermal tissue injury. This may have implications for hemostasis, scarring, and perioperative morbidity. The objective of this study is to assess histopathologic changes in prostatic tissue after bipolar transurethral vaporization of the prostate. PATIENTS AND METHODS: Male patients older than 40 years with a diagnosis of benign prostatic hyperplasia (BPH) who elected to undergo bipolar transurethral vaporization of the prostate were included in this study. Patients were excluded if they had a previous transurethral resection of the prostate (TURP) or prostate radiation therapy. An Olympus button vaporization electrode was used to vaporize prostate tissue. A loop electrode was then used to obtain a deep resection specimen. The vaporized and loop resection surfaces were inked and sent for pathologic analysis to determine the presence of gross histologic changes and the depth of penetration of the bipolar vaporization current. RESULTS: A total of 12 men underwent bipolar TURP at standard settings of 290 W cutting and 145 W coagulation current. Mean patient age was 70±10.2 years (range 56-88 years). Mean surgical time was 48.7±20.2 minutes (range 30-89 min). Mean depth of thermal injury was 2.4±0.84 mm (range 0.3-3.5 mm). Histopathologic evaluation demonstrated thermal injury in all specimens, but no gross char was encountered. CONCLUSIONS: In bipolar systems, resection takes place at much lower peak voltages and temperatures compared with monopolar systems. Theoretically, this leads to less collateral thermal damage and tissue char. Our tissue study illustrates that the button vaporization electrode achieves a much larger depth of penetration than previous studies of bipolar TURP. This may be because thermal injury represents a gradual continuum of histologic changes.