Ran Katz

Hebrew University of Jerusalem, Yerushalayim, Jerusalem District, Israel

Are you Ran Katz?

Claim your profile

Publications (54)93.17 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Introduction: Bones represent the most common metastatic sites in prostate cancer (PCa) patients, and in addition with androgen deprivation therapy, they represent the causative reasons of bone mineral density loss and the onset of skeletal-related events.Areas covered: An extensive search of PubMed/Medline was performed to identify randomized, Phase II/III controlled trials reporting results regarding the prevention of skeletal morbidity in patients with PCa.Expert opinion: Preventing bone health is an imperative issue for preserving quality of life and elongate survival and, thus, a concerted effort should be made to monitor skeletal changes and to apply treatment for preventing bone loss. Although several agents have received approval for routine use, it is of paramount importance to identify the appropriate patients who would mostly be benefited by the use of these agents with attention to documenting the toxicity and economic implications. Additionally, it remains to be justified the frequency of administration in order to balance the efficacy and the potential complications.
    Expert Opinion on Pharmacotherapy 09/2014; · 2.86 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To create a model for prediction of stone radiopacity based on computed tomography (CT) parameters.
    Urology 08/2014; · 2.42 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Objective: To analyze the epidemiological and clinical characteristics and therapeutic outcomes of patients with cystine stones and to compare them with the characteristics of patients with calcium oxalate stones. Patients and methods: We identified 30 patients with cystine stones who were consulted in our department from January 1972 until December 2013. These patients were matched and paired, based on age and gender, to 30 calcium oxalate stone formers who were diagnosed and treated in our department from January 2011 until December 2013. Results: Cystine stones were significant larger in size (p<0.001) while most of them were found in the kidney (p=0.002). Patients with cystinuria had their first stone episode in earlier age (p<0.001) compared to patients with calcium oxalate stones. No significant differences were observed regarding the frequency and the severity of symptoms. Both groups had similar visits per year in outpatient clinic, emergency room admissions and episodes of febrile urinary tract infections. Cystine stone formers had undergone significantly higher number of procedures for stone removal (p<0.001). No statistical differences were found in the compliance rates between the groups. Patients with cystine stones had significantly higher serum creatinine levels (p=0.005). Conclusions: Cystine stones present in an earlier age and have the likehood to be large in size. Patients with cystine stones undergo a greater number of procedures, and they have a greater risk to develop chronic renal impairment.
    Journal of endourology / Endourological Society 08/2014; · 1.75 Impact Factor
  • Source
  • [Show abstract] [Hide abstract]
    ABSTRACT: We describe an unusual presentation of metastatic lung adenocarcinoma as malignant retroperitoneal fibrosis (MRPF). The diagnostic challenge, due to the small solitary lung mass and absence of a discrete retroperitoneal mass, was overcome by diagnostic laparoscopy. Molecular analysis of tissue acquired was positive for ALK gene rearrangement. Treatment of the patient with crizotinib reversed MRPF. He was weaned off the nephrostomy tubes and is with stable renal function 11 months after diagnosis.
    Canadian Urological Association journal = Journal de l'Association des urologues du Canada 07/2013; 7(7-8):E490-4. · 1.66 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: BACKGROUND: The management of patients with high-grade non muscle invasive bladder cancer (NMIBC) brings diagnostic and therapeutic challenges. In the current study, we sought to study the natural history of progression to "secondary" muscle-invasive bladder cancer (MIBC)-cancer that developed during follow up of patients presenting with non-muscle invasive bladder cancer (NMIBC). METHODS: Between 1998 and 2008, 760 patients were treated for bladder cancer. Primary MIBC (>=T2) tumors (present upon presentation) were diagnosed in 114 patients. All patients with high-grade NMIBC were treated with intravesical BCG. Mean follow-up was 44 months. RESULTS: Forty patients (6.1%) developed secondary MIBC after a mean period of 21 months from initial diagnosis of bladder cancer. The 2- and 5-year disease-specific survival rates were better for patients with secondary MIBC (90% and 56% compared to 69% and 42% for patients with primary disease, p=0.03). The Kaplan-Meier curves of the two groups were parallel but displaced by approximately 2 years. CONCLUSION: In the current series, MIBC progression occurred among initially presenting patients with NMIBC in 6.1%. In most patients, the initial diagnosis of NMIBC is correct and muscle invasion occurs after a mean period of about 2 years. This supports a non-radical approach in patients with high-grade T1, Ta or Tis. Meticulous follow-up with liberal biopsy of any suspicious lesion may provide early diagnosis of invasive disease.
    BMC Urology 05/2013; 13(1):23. · 1.69 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The objective of the study is to assess the etiology and prognosis of gross hematuria (GH) in patients with carcinoma of the prostate (CAP). From 1991 to 2011, 81 men (mean age 74.3 years, SD 6.5) with CAP were hospitalized with GH. Primary treatment of CAP was radical surgery in 13 patients (group 1) and nonsurgical therapy in 68 (group 2), mostly radiotherapy (35 cases) and hormonal treatment (25 cases). The common etiologies of GH in group 1 were bladder cancer (38.5%) and urinary infection (23%). In contrast, CAP itself caused GH in 60% of the patients in group 2. Thirty-nine patients (48%) required transurethral surgery to manage GH which was effective in all cases; nevertheless, the prognosis of group 2 patients was dismal with median overall survival of 13 months after sustaining hematuria, compared to 50 months in group 1 (P = 0.0015). We conclude that the etiology of GH in patients with CAP varies according to primary treatment. After radical prostatectomy, it is habitually caused by bladder cancer or infection. When the primary treatment is not surgical, GH is most commonly due to CAP itself. Although surgical intervention is effective in alleviating hematuria of these patients, their prognosis is dismal.
    ISRN surgery. 01/2013; 2013:685327.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: OBJECTIVE: To evaluate the importance of stone composition and crystallite size in the formation of ultimate stone burden. Crystallite is the smallest building block, which is unique in size and architecture for each type of stone component. Currently, the knowledge about the clinical importance of crystallite size is very limited. METHODS: The results of quantitative X-ray diffraction phase analysis performed on 286 kidney stones extracted during endourological surgery or expelled spontaneously were retrospectively analyzed. Stone composition and crystallite size were determined and were compared to the burden occupying the pelvicalyceal system. RESULTS: A total of 286 renal stones were analyzed. Stones were low burden and high burden in 242 and 44 of cases, respectively. We observed statistically significant association of phosphates and urates with high-burden stones in contrast to oxalates, which formed mainly low-burden stones. Crystallite sizes were available for 179 stones. Large-sized crystallites of calcium oxalate monohydrate and hydroxyl apatite formed low-burden stones, whereas small-sized crystallites formed staghorn stones. Struvite and urates had a uniform average size of crystallites. CONCLUSION: Oxalate stones have statistically significant association with smaller stones, whereas high-burden calculi are significantly associated with urates and phosphates, especially the struvite type. The smaller the crystallite size is to start with, the larger will be the ultimate stone burden. This rule is followed by calcium oxalate monohydrate and Apatite minerals.
    Urology 09/2012; · 2.42 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Background:The aim of radical prostatectomy (RP) is the complete removal of the prostate gland with negative surgical margins. The presence of cancer at the surgical margin is associated with higher probability of disease progression. Current methods of intraoperative margin assessment are inaccurate or time-consuming.The study goal was to evaluate the ability of a novel device (Dune Medical Devices) to differentiate between cancer and BPH.Methods:A total of 49 patients undergoing RP in four medical centers between November 2007 and May 2008 were enrolled in this study.The device was applied to numerous intra- and extra-capsular sites of freshly excised RP specimens. Measurement sites were accurately marked and analyzed histologically. The ability of the device to differentiate between malignant and nonmalignant sites was assessed.Results:A total of 15 156 measurements from 45 patients were analyzed. Differentiation of the intra-capsular malignant sites from extra-capsular nonmalignant sites (bladder neck and apex regions) depends on the cancer feature size. Differentiation was achieved with sensitivity and specificity of 93.6 (95% confidence interval (CI): 88-98) and 94.1 (95% CI: 93-95), respectively, at feature sizes at or >0.8 mm in diameter. The device was able to discriminate between all intra-capsular malignant (with feature sizes down to a few cells) and nonmalignant measurement sites, with sensitivity and specificity of 80.8 (95% CI: 73-87) and 68.4 (95% CI: 67-69), respectively.Conclusions:First results from a radio-frequency near-field spectroscopy sensor look promising for differentiation between cancer and benign prostate tissue. The sensor's dimensions (radius of ∼1 mm) and design enable use in open, laparoscopic and robotic RP to evaluate the surgical margins intraoperatively.Prostate Cancer and Prostatic Disease advance online publication, 11 September 2012; doi:10.1038/pcan.2012.34.
    Prostate cancer and prostatic diseases 09/2012; · 2.10 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Biofilms on the surfaces of urinary catheters are among the pivotal factors for recurrent and persistent infections in urology. Many techniques have been investigated and applied for eradication of these biofilms--but with no full success. The aim of this study was to examine the effect of sustained release medicated varnish, releasing chlorhexidine, on the formation of biofilm on the urinary catheter surface in an in-vitro model. A batch model was used to test the antibacterial/antibiofilm effect of the sustained release varnish: Catheter pieces coated with sustained release varnishes were placed in bacterial growth medium that was infected with Pseudomonas aeruginosa for 96 hours. Various concentrations of chlorhexidine impregnated in the varnish were tested. After the incubation period, the catheter pieces were assessed for biofilm formation by measuring the optical density, colony-forming units, and using confocal laser scanning microscopy, and electron scanning microscopy. Biofilm growth measurement (colony-forming units [CFU]) on the catheter surface coated with the various concentrations of chlorhexidine in sustained released varnish revealed a 94% reduction with 1% chlorhexidine (P<0.0001) and 43% reduction with 0.1% chlorhexidine (P=0.08) coated varnish in comparison with a positive control or the placebo varnish in preventing biofilm growth of P. aeruginosa. These biologic assays were confirmed using confocal and electron microscopy. Of the various tested concentrations of sustained release varnishes, the 1% chlorhexidine concentration has demonstrated the superior antibiofilm effect on urinary catheters with P. aeruginosa. Although similar varnishes are used in dentistry, it needs extended research in animals before applying this technology in human trials.
    Journal of endourology / Endourological Society 12/2011; 26(1):26-31. · 1.75 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To examine the hypothesis that the risk of high-grade bladder cancer can be predicted using noninvasively obtained data. We retrospectively analyzed the database of 431 patients that had transurethral resection of first-time bladder tumors between June 1998 and December 2009. Pre-operative parameters evaluated were: patients' age; gender; sonographic tumor diameter, number and location of tumor inside the bladder; presence of hydronephrosis, and results of urinary cytology. Parameters that showed significance in multivariate analysis were incorporated into the nomogram. Multivariate analysis of the data showed that patient's age, the presence of hydronephrosis, sonographic tumor diameter (risk of a high-grade tumor: 14, 29, 43.3, 55.7 and 69.4% at diameters: 0.5-1.5, 1.6-2, 2.1-2.5, 2.6-3 and >3 cm, respectively), location of tumor in the bladder (risk of high-grade tumor: 28.8, 47, 67.5 and 90.5% in the lateral walls, posterior/base, anterior and dome, respectively), and urinary cytology were all highly significant and independent predictors of high-grade tumors. A nomogram constructed using these variables scored an area of 0.853 in the ROC curve. The risk of high-grade bladder tumor can be accurately predicted using non-invasively obtained information. This prediction can help to triage patients with newly detected bladder cancer for biopsy.
    Urologia Internationalis 08/2011; 87(3):319-24. · 1.07 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Urothelial carcinomas have an established propensity for divergent differentiation. Most of these variant tumors are muscle invasive but not all. The response of non muscle invasive variant tumors to intravesical immunotherapy with BCG is not established in the literature, and is reported here. Between June 1995 and December 2007, 760 patients (mean age of 67.5 years) underwent transurethral resection of first time bladder tumors in our institution. Histologically variant tumors were found in 79 patients (10.4%). Of these 57 patients (72%) of them had muscle-invasive disease or extensive non-muscle invasive tumors and remaining 22 patients (28%) were treated with BCG immunotherapy. These included 7 patients with squamous differentiation, 4 with glandular, 6 with nested, 4 with micropapillary and 1 patient with sarcomatoid variant. The response of these patients to immunotherapy was compared with that of 144 patients having high-grade conventional urothelial carcinomas. Median follow-up was 46 months. The 2 and 5-year progression (muscle-invasion) free survival rates were 92% and 84.24% for patients with conventional carcinoma compared to 81.06% and 63.16% for patients with variant disease (P=0.02). The 2 and 5-year disease specific survival rates were 97% and 91.43% for patients with conventional carcinoma compared to 94.74 % and 82% for patients with variant disease (P=0.33). 5 patients (22.7%) of variant group and 13 patients (9.03%) of conventional group underwent cystectomy during follow-up (P=0.068).Patients with non-muscle invasive variants of bladder cancers can be managed with intravesical immunotherapy if tumor is not bulky (>4 cm). Although progression to muscle invasive disease is more common than in conventional group and occurs in about 40% of the patients, life expectancy is similar to patients with conventional high-grade urothelial carcinomas provided that follow-up is meticulous.
    Rare tumors 04/2011; 3(2):e22.
  • Journal of Urology - J UROL. 01/2011; 185(4).
  • [Show abstract] [Hide abstract]
    ABSTRACT: Current urologic laparoscopic procedures include preservation of locoregional nerve fibers. The use of electrical coagulation is limited because of tissue conductance of current and heat production. While ultrasonic coagulation does not use electricity, heat is still produced. We designed an animal model to characterize the heat spread around ultrasonic devices and assess whether it is neurodestructive. 10 rats were anesthetized; their skin was reflected, exposing the muscles. An ultrasonic probe was introduced into the tissue, and coagulation was performed for 10 seconds. Tissue temperature was measured using four thermocouples, at distances of 4, 8, 12, and 16 mm from the probes and in a circumferential manner. Thermal mapping of the probes was performed with an infrared camera. Further, four rats were anesthetized; the skin above their inner thighs was reflected bilaterally exposing the "nervus ischiadicus." Coagulation was performed in varying distances from the nerve on one side while the other served as control. One week later, the animals were sacrificed, and the nerves were obtained. Silver staining was used to assess the vitality of the axons. In distances of 4 to 8 mm from the device, temperatures as high as 81°C were recorded, and silver staining showed severe axonal damage. Although ultrasonic coagulation is efficient, local heat production may reach neurodestructive levels with a typical tissue distribution pattern. These features should be addressed during laparoscopic dissection and when considering nerve-sparing procedures.
    Journal of endourology / Endourological Society 10/2010; 24(11):1857-62. · 1.75 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: From 1985 to August 2007 we have performed 15,324 shockwave lithotripsy (SWL) treatments using the Dornier HM3 lithotripter. We studied trends in the characteristics of treatments and patients. Patient data were recorded in a computerized database. Changes in characteristics of patients and stones treated during this period were reviewed. A total of 15,324 treatments were performed on 10,734 patients. The following trends were observed: (1) Stone size: A significant increase in the proportion of patients treated for stones up to 10 mm in diameter, no change for stone size of 10 to 20 mm, and a decrease in stones larger than 20 mm in diameter. (2) Stone location: A significant increase in the proportion of patients treated for proximal and distal ureteral calculi, whereas a significant decrease in those with renal pelvic and staghorn stones. (3) Auxiliary procedures: A significant increase in the use of perioperative procedures (stents or ureteral catheters) ranging from 20% during the mid-1980s up to 60% in the year 2007. (4) Presenting symptoms: A significant increase in the percentage of patients referred with pain and a significant decrease in the percentage of patients referred with signs of infection. (5) Repeat SWL: A total of 13% of the patients required a second SWL for the same stone within 90 days of the first procedure. (6) Complication rate: This rate was relatively low, ranging from 1% to 6% per year. The evolvement of endourological procedures and techniques resulted in a decreased referral of large kidney stones for SWL. Advanced diagnostic modalities increased the diagnosis of renal colic in patients presenting with pain, and consequently their referral rate and timing for SWL treatment. The use of stents increased because of referral of patients with obstructing stones and infection or for prevention of posttreatment obstruction.
    Journal of endourology / Endourological Society 04/2010; 24(4):609-14. · 1.75 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Most urothelial carcinomas are exophytic, but some tumors exhibit subepithelial components, either in the form of endophytic growth pattern (EGP) or as von Brunn's nests involvement (VBNI). The purpose of this study was to investigate the frequency, inter-relations and clinical significance of these forms of subepithelial neoplasia in urothelial carcinoma. Between June 1995 and December 2007, 760 patients (mean age of 67.5 years) underwent transurethral resection of bladder tumors in our institution, including 478, 157, and 112 patients with stage Ta, T1, and ≥T2 disease, respectively. Isolated or concomitant Tis were present in 137 (18%) patients. Median postoperative follow-up period was 53 months. EGP was found in 86 cases (11.3%) and VBNI in 30 (3.9%) patients. Both forms of subepithelial growth were significantly more common in higher stage and grade tumors and were associated with each other. Multivariate analysis showed that EGP is an independent prognostic factor of stage progression (HR 4.6, P < 0.0001) and disease specific mortality (HR 2.6, P = 0.001) but not of tumor recurrence (HR 1.2, P = 0.51). VBNI was found an independent prognostic factor of tumor progression (HR 5.1, P < 0.0001), but neither of tumor recurrence nor disease specific mortality. Subepithelial growth is not an uncommon in bladder cancer. It is more frequent in high-grade and high-stage tumors. The findings of this study suggest that subepithelial growth carries a higher risk for stage progression (EGP and VBNI) and mortality (EGP), but not tumor recurrence.
    Urologic Oncology 03/2010; 30(1):49-54. · 3.65 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To identify risk factors for fever after shockwave lithotripsy (SWL) and suggest guidelines for prophylactic antimicrobial treatment. Between 1985 and 2007, a total of 15,324 SWL procedures were performed in our institution using the Dornier HM3 lithotripter. Because stone analyses were not available in the majority of patients, management of stones larger than 2 cm in diameter were excluded from this analysis to minimize the ratio of struvite stones as a possible cause for postprocedural fever. In this analysis, 11,500 SWL treatments were included. Clinical parameters before, during, and after treatments were prospectively registered using a computerized database. Potential risk factors for fever after SWL were evaluated. Fever >38.0 degrees C developed in 161 (1.4%) patients. The risk factors for fever after SWL were: A positive urine culture (P < 0.05), an indwelling nephrostomy tube or stent during the procedure (P < 0.001), lithotripsy of kidney or upper ureteral stones (P < 0.05) and preoperative symptomatic urinary tract infection (UTI) (P < 0.05) or sepsis (P < 0.05). Lithotripsy of mid and lower ureteral stones, stone size, and the use of ureteral catheters during the procedures were not associated with increased risk of fever after SWL. Fever (>38.0 degrees C) develops in only 1.4% of the patients undergoing SWL. Therefore, prophylactic antibiotic treatment is not indicated in all patients. Selective prophylactic treatment is recommended in patients who present with UTI, kidney or upper ureteral stones, and those for whom a nephrostomy tube or stent is necessary.
    Journal of endourology / Endourological Society 02/2010; 24(2):277-81. · 1.75 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Bladder neck closure necessitates lifelong clean intermittent catheterization. Concerns have been raised regarding well-being and compliance in patients on long-term clean intermittent catheterization. Noncompliance may result in subsequent hydronephrosis, incontinence, infection, cystolithiasis and perforation. We analyzed our long-term results with bladder neck closure followed at least 10 years for patient compliance with clean intermittent catheterization, upper tract preservation, continence, complications and subsequent procedures. All patients followed at least 10 years after bladder neck closure were included in this study. Seven boys and 5 girls with a mean age of 7.0 years and urinary incontinence underwent bladder neck closure and continent urinary diversion between 1993 and 1998. The primary diagnosis was exstrophy in 5 patients, spinal dysraphism in 3, trauma in 2, sacral agenesis in 1 and a duplicated hindgut in 1. Mean followup was 12.4 years (range 10 to 14). All patients performed clean intermittent catheterization 4 to 6 times daily. Hydronephrosis improved or remained stable in the 11 patients who underwent bladder augmentation. Mild new hydronephrosis developed in 1 patient and resolved after increasing clean intermittent catheterization frequency. Bladder neck closure successfully cured incontinence in all of the last 6 patients who underwent modified bladder neck closure with a posterior bladder neck flap, while 2 of the earlier 6 bladder neck closures required revision for a subsequent 100% success rate. Additional operations were required in 6 patients. To our knowledge this is the longest followup after bladder neck closure reported in the literature. Patient compliance with long-term clean intermittent catheterization is good after bladder neck closure. Bladder neck closure provides excellent long-term safety for the upper urinary tract and continence. It is associated with relatively low morbidity, which is correctible.
    The Journal of urology 09/2009; 182(4 Suppl):1797-801. · 3.75 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The sophistication of percutaneous nephrolithotomy and ureteroscopy challenges the efficacy of ESWL for urolithiasis in prepubertal patients. We evaluated our long-term experience with ESWL in these patients and determined its efficiency. We retrospectively reviewed the charts of all prepubertal patients who underwent ESWL. We evaluated the need for tubing, the 3-month stone-free rate, the need for additional ESWL, and the effect of stone size and location, and cystinuria on the 3-month stone-free rate. Between 1986 and 2008, 119 males and 97 females with a mean age of 6.6 years who had urolithiasis underwent ESWL using the Dornier HM3 lithotriptor. We treated 157 children with renal calculi with an average +/- SD diameter of 14.9 +/- 8.9 mm, of whom 66 (42%) required a tube in the urinary system. The 3-month stone-free rate was 80% and 31 patients (19.7%) needed an additional procedure. Stone location did not affect the stone-free rate but stone size did. We treated 59 patients for ureteral stones with an average stone length of 9.5 +/- 4.8 mm, of whom 41 (69%) required tube insertion. The 3-month stone-free rate was 78% and 13 patients (22%) needed an additional procedure. The 3-month stone-free rate did not depend on stone location or size. The rate was 37.5% in patients with cystinuria and 82.5% in all others (p <0.0001). Six patients (2.8%) had complications. The 3-month stone-free rate after ESWL in prepubertal patients is 80% and 20% of patients require additional procedures. ESWL is most effective for kidney stones less than 11 mm. ESWL has inferior results for cystine stones compared to other calculi. Complications are rare.
    The Journal of urology 08/2009; 182(4 Suppl):1835-9. · 3.75 Impact Factor
  • Journal of Urology - J UROL. 01/2009; 181(4):640-640.

Publication Stats

272 Citations
93.17 Total Impact Points

Institutions

  • 1997–2014
    • Hebrew University of Jerusalem
      • • Department of Urology
      • • Department of Surgery
      Yerushalayim, Jerusalem District, Israel
  • 1997–2013
    • Hadassah Medical Center
      • Department of Urology
      Yerushalayim, Jerusalem District, Israel
  • 2008
    • The University of Chicago Medical Center
      • Section of Urology
      Chicago, Illinois, United States