A classification tree for the prediction of benign versus malignant disease in patients with small renal masses.

INTRODUCTION: To develop a classification tree for the preoperative prediction of benign versus malignant disease in patients with small renal masses. MATERIALS AND METHODS: This is a retrospective study including 395 consecutive patients who underwent surgical treatment for a renal mass < 5 cm in maximum diameter between July 1st 2001 and June 30th 2010. A classification tree to predict the risk of having a benign renal mass preoperatively was developed using recursive partitioning analysis for repeated measures outcomes. Age, sex, volume on preoperative imaging, tumor location (central/peripheral), degree of endophytic component (1%-100%), and tumor axis position were used as potential predictors to develop the model. RESULTS: Forty-five patients (11.4%) were found to have a benign mass postoperatively. A classification tree has been developed which can predict the risk of benign disease with an accuracy of 88.9% (95% CI: 85.3 to 91.8). The significant prognostic factors in the classification tree are tumor volume, degree of endophytic component and symptoms at diagnosis. As an example of its utilization, a renal mass with a volume of < 5.67 cm3 that is < 45% endophytic has a 52.6% chance of having benign pathology. Conversely, a renal mass with a volume ≥ 5.67 cm3 that is ≥ 35% endophytic has only a 5.3% possibility of being benign. CONCLUSIONS: A classification tree to predict the risk of benign disease in small renal masses has been developed to aid the clinician when deciding on treatment strategies for small renal masses.

Growth kinetics of renal masses: analysis of a prospective cohort of patients undergoing active surveillance.

BACKGROUND: Active surveillance (AS) represents a treatment option for renal masses in patients who are not surgical candidates either because of existing comorbidities or patient choice. Among renal masses undergoing AS, some grow rapidly and require treatment or progress to metastatic disease. Patient and tumour characteristics related to this more aggressive behaviour have been poorly studied. OBJECTIVE: To report the analysis of a multi-institutional cohort of patients undergoing AS for small renal masses. DESIGN, SETTING, AND PARTICIPANTS: This prospective study included 82 patients with 84 renal masses who underwent AS in three Canadian institutions between July 2001 and June 2009. INTERVENTION: All patients underwent AS for renal masses presumed to be renal cell carcinoma (RCC) as based on diagnostic imaging. MEASUREMENTS: Age, sex, symptoms at presentation, maximum diameter at diagnosis (cm), tumour location (central/peripheral), degree of endophytic component (1-100%), and tumour consistency (solid/cystic) were used to develop a predictive model of the tumour growth rate using binary recursive partitioning analysis with a repeated measures outcome. RESULTS AND LIMITATIONS: With a median follow-up of 36 mo (range: 6-96), the mean annual renal mass growth rate for the entire cohort was 0.25 cm/yr (standard deviation [SD]: 0.49 cm/yr). Only one patient (1.2%) developed metastatic RCC. Amongst all variables, maximum diameter at diagnosis was the only predictor of tumour growth rate, and two distinct growth rates were identified. Masses that are ≥2.45 cm in largest diameter at diagnosis grow faster than smaller masses. This series was limited by its moderate sample size, although it is the largest published prospective series to date. CONCLUSIONS: We confirm that most renal masses grow slowly and carry a low metastatic potential. Tumour size is a predictor of tumour growth rate, with renal masses <2.45 cm growing more slowly than masses >2.45 cm.

Multi-drug resistant E.coli urosepsis in physicians following transrectal ultrasound guided prostate biopsies--three cases including one death.

Three male physicians underwent transrectal ultrasound guided prostate biopsies for elevated prostate-specific antigen levels or irregular digital rectal exam findings. All three of these patients developed urosepsis secondary to multi-drug resistant organisms despite antibiotic prophylaxis. There are increasing reports of infectious complications following prostate biopsy caused by multi-drug resistant organisms. These cases highlight the potentially lethal risks to healthcare workers who are more likely to harbor multi-drug resistant organisms than the general population. Further research into preoperative assessment and appropriate antibiotic prophylaxis in all potentially high risk patients is warranted.

Randomized double-blind study of immunoprophylaxis with basiliximab, a chimeric anti-interleukin-2 receptor monoclonal antibody, in combination with mycophenolate mofetil-containing triple therapy in renal transplantation.

BACKGROUND: Acute rejection remains a major problem in renal transplantation. Immunoprophylaxis with basiliximab (Simulect) has achieved significant reductions in acute rejection episodes in renal allograft recipients receiving dual immunosuppression. This study explored the tolerability and cumulative benefit of combining basiliximab with triple-drug therapy-cyclosporine (USP Modified, Neoral), mycophenolate mofetil, and steroids. METHODS: In a randomized, double-blind, placebo-controlled, multicenter study, 123 kidney transplant recipients received either basiliximab at 20 mg before transplantation (day 0) and 20 mg on day 4 (n=59), or placebo (n=64). All received triple-drug immunosuppression and were followed for 6 months. RESULTS: Tolerability of basiliximab was equivalent to placebo, with no increase in serious adverse events, infection, malignancy, or posttransplant lymphoproliferative disorder. At 6 months, there were trends in favor of basiliximab over placebo in the incidences of first biopsy-confirmed acute rejection (15.3% vs. 26.6%, P=NS) and of acute rejection treated with antibody (5.1% vs. 15.6%, P=NS). Kaplan-Meier estimates at 4 weeks and 6 months were significantly in favor of basiliximab treatment for first acute rejection, biopsy-confirmed rejection, rejection episodes treated with antibody therapy, and treatment failure. Renal function improved more rapidly in the basiliximab group, with mean creatinine clearance at week 2 being 54.7 mL/min versus 43.2 mL/min for placebo (P=0.034). At 12 months, patient survival was 100% in both groups; graft survival was 94.9% with basiliximab and 92.2% with placebo. CONCLUSIONS: Basiliximab immunoprophylaxis is safe, well tolerated, and shows a trend toward reduction in number of acute rejection episodes in renal transplant patients receiving cyclosporine, mycophenolate mofetil, and steroids.

T-cell/periodic acid-Schiff stain: a useful tool in the evaluation of tubulointerstitial infiltrates as a component of renal allograft rejection.

Distinguishing between tubulitis and tubulointerstitial mononuclear cell infiltrates and determining the severity of tubulitis are critical components of diagnosing and grading renal allograft rejection using the 1993 Banff schema, the revised 1997 Banff schema, or the Cooperative Clinical Trials in Transplantation grading system. We describe a novel staining method, the T-PAS stain (CD3 and periodic acid-Schiff), which removes some of the subjectivity in the evaluation of tubulointerstitial infiltrates in renal allograft biopsies. The method simply combines two routine stains, immunoperoxidase staining for T cells (CD3) and periodic acid-Schiff (PAS) staining for tubular basement membrane, on the same section.