Distinguishing Benign Renal Tumors with an Oncocytic Gene Expression (ONEX) Classifier

Renal oncocytoma (RO) accounts for 5% of renal cancers and generally behaves as a benign tumor with favorable long-term prognosis. It is difficult to confidently distinguish between benign RO and other renal malignancies, particularly chromophobe renal cell carcinoma (chRCC). Therefore, RO is often managed aggressively with surgery. We sought to identify molecular biomarkers to distinguish RO from chRCC and other malignant renal cancer mimics. In a 44-patient discovery cohort, we identified a significant differential abundance of nine genes in RO relative to chRCC. These genes were used to train a classifier to distinguish RO from chRCC in an independent 57-patient cohort. The trained classifier was then validated in five independent cohorts comprising 89 total patients. This nine-gene classifier trained on the basis of differential gene expression showed 93% sensitivity and 98% specificity for distinguishing RO from chRCC across the pooled validation cohorts, with a c-statistic of 0.978. This tool may be a useful adjunct to other diagnostic modalities to decrease the diagnostic and management uncertainty associated with small renal masses and to enable clinicians to recommend more confidently less aggressive management for some tumors. PATIENT SUMMARY: Renal oncocytoma is generally a benign form of kidney cancer that does not necessarily require surgical removal. However, it is difficult to distinguish renal oncocytoma from other more aggressive forms of kidney cancer, so it is treated most commonly with surgery. We built a classification tool based on the RNA levels of nine genes that may help avoid these surgeries by reliably distinguishing renal oncocytoma from other forms of kidney cancer

Use of haemostatic agents and glues during laparoscopic partial nephrectomy: a multi-institutional survey from the United States and Europe of 1347 cases

OBJECTIVES: Laparoscopic partial nephrectomy (LPN) is a technically challenging procedure for the management of renal tumours. Major complications of LPN include bleeding and urine leakage. Haemostatic agents (HAs) and/or glues may reduce haemorrhage and urine leakage. We sought to examine the current practice patterns for urologists performing LPN with regard to HA use and its relationship with bleeding and urine leakage. MATERIALS AND METHODS: A survey was sent via e-mail to urologists currently performing LPN in centres in the United States and Europe. We queried the indications for HA/glue usage, type of HAs/glues used, and whether concomitant suturing/bolstering was performed. In addition, the total number of LPNs performed, laparoscopic tools used to resect the tumour, tumour size, and tumour position were queried. RESULTS: Surveys suitable for analysis were received from 18 centres (n=1347 cases). HAs and/or glues were used in 1042 (77.4%) cases. Mean tumour size was 2.8cm, with 79% of the tumours being defined as exophytic and 21% deep. The HAs and glues used included gelatin matrix thrombin (FloSeal), fibrin gel (Tisseel), bovine serum albumin (BioGlue), cyanoacrylate glue (Glubran), oxidized regenerated cellulose (Surgicel), or combinations of these. Sixteen centres performed concomitant suturing/bolstering. The overall postoperative bleeding requiring transfusion and urine leakage rates were 2.7% and 1.9%, respectively. CONCLUSIONS: The use of HAs and/or glues is routine in most centres performing LPN. The overall haemorrhage and urine leakage rates are low following LPN. More studies are needed to assess the potential role of HAs and/or glues in LP