Identification of patient and tumor characteristics associated with nondiagnostic biopsies is necessary to improve prebiopsy counseling and patient selection. We reviewed the clinical records and prebiopsy imaging of all patients treated with percutaneous biopsy for a renal mass 7 cm or less. Univariate and multivariate logistic regression models were constructed to examine the association between biopsy outcome and clinical/radiographic features. A total of 565 biopsies of renal tumors 7 cm or less in 525 patients were included in the study. There was no significant difference in age, body mass index, Charlson comorbidity score or gender between the patient cohorts with diagnostic and nondiagnostic biopsy. In 83 of 565 patients (14.7%) overall and in 72 of the 413 (17.4%) with a mass of 4 cm or less the biopsy findings were nondiagnostic. Overall 14.7% of masses were cystic and 85.3% were solid with a median tumor size of 2.75 cm (IQR 2.05-4.25). Independent predictors of nondiagnostic biopsy included cystic features, enhancement less than 20 HU, left tumor, tumor diameter and skin-to-tumor distance. The nondiagnostic rate of repeat biopsies was 20.8%, which did not statistically differ from the nondiagnostic rate at the initial renal mass biopsy attempt. Radiologist or pathologist experience was not associated with the biopsy nondiagnostic rate. In 7 of 565 patients (1.2%) hospital admission was required for adverse events after biopsy. Nondiagnostic renal mass biopsies are more common in cystic, nonenhancing, small masses when patients have a skin-to-tumor distance of 13 cm or greater. Excluding patients with these criteria decreased the nondiagnostic rate from 14.7% to 8.7%.

The traditional pathologic grading for human renal cell carcinoma (RCC) has low concordance between biopsy and surgical specimen. There is a need to investigate adjunctive pathology technique that does not rely on the nuclear morphology that defines the traditional grading. Changes in collagen organization in the extracellular matrix have been linked to prognosis or grade in breast, ovarian, and pancreatic cancers, but collagen organization has never been correlated with RCC grade. In this study, we used Second Harmonic Generation (SHG) based imaging to quantify possible differences in collagen organization between high and low grades of human RCC. A tissue microarray (TMA) was constructed from RCC tumor specimens. Each TMA core represents an individual patient. A 5 μm section from the TMA tissue was stained with standard hematoxylin and eosin (H&E). Bright field images of the H&E stained TMA were used to annotate representative RCC regions. In this study, 70 grade 1 cores and 51 grade 4 cores were imaged on a custom-built forward SHG microscope, and images were analyzed using established software tools to automatically extract and quantify collagen fibers for alignment and density assessment. A linear mixed-effects model with random intercepts to account for the within-patient correlation was created to compare grade 1 vs. grade 4 measurements and the statistical tests were two-sided. Both collagen density and alignment differed significantly between RCC grade 1 and RCC grade 4. Specifically, collagen fiber density was greater in grade 4 than in grade 1 RCC (p < 0.001). Collagen fibers were also more aligned in grade 4 compared to grade 1 (p < 0.001). Collagen density and alignment were shown to be significantly higher in RCC grade 4 vs. grade 1. This technique of biopsy sampling by SHG could complement classical tumor grading approaches. Furthermore it might allow biopsies to be more clinically relevant by informing diagnostics. Future studies are required to investigate the functional role of collagen organization in RCC.

Careful selection is critical to identify those with metastatic renal cell carcinoma who are most likely to benefit from cytoreductive nephrectomy. Surgery in patients who have metastatic renal cell carcinoma with tumor thrombus is complex and may not benefit some patients with poor overall survival. We evaluated whether preoperative variables or risk stratification systems could predict overall survival following cytoreductive nephrectomy. Prognostic factors for overall survival after surgery were evaluated in patients who had metastatic renal cell carcinoma with venous tumor thrombus at 5 institutions from 2000 to 2014. Prognostic variables, including metastatic renal cell carcinoma risk models, were evaluated for associations with overall survival. Multivariable analysis was used to determine independent associations of preoperative variables with overall survival. A total of 427 patients with metastatic renal cell carcinoma were identified with tumor thrombus. Patients with inferior vena cava thrombus above the diaphragm had shorter median overall survival vs those with renal vein only thrombus (9.2 months, IQR 4.2-30.8, vs 21.7, IQR 7.7-42.8, p = 0.0165). Individual risk factors from prognostic models were evaluated among other preoperative characteristics for associations with overall survival in 122 patients (32%) who died within 270 days of surgery. Independent predictors of overall survival included lactate dehydrogenase greater than the upper limit of normal (p = 0.003), systemic symptoms (p = 0.003), inferior vena cava thrombus above the diaphragm (p = 0.02) and sarcomatoid features (p = 0.005). Poor overall survival following cytoreductive nephrectomy in patients with metastatic renal cell carcinoma with tumor thrombus is associated with inferior vena cava thrombus above the diaphragm, poor risk group, systemic symptoms or sarcomatoid dedifferentiation. Patients with expected poor overall survival should be considered for preoperative systemic therapy clinical trials.

Purpose: Percutaneous radiofrequency ablation and cryoablation are accepted alternative treatments for small renal cell carcinomas (RCC) in high-risk patients. The recent development of high-powered microwave (MW) ablation offers theoretical advantages over existing ablation systems, including higher tissue temperatures, more reproducible ablation zones, and shorter procedural times. The purpose of this study is to review the feasibility, safety, and early efficacy of a novel high-powered percutaneous MW ablation system to treat RCC. Methods: An institutional database identified 53 consecutive patients with biopsy-proven RCC ≤4 cm (55 tumors) who were treated with percutaneous MW ablation using a novel MW ablation system. All patients had percutaneous renal mass biopsy, which identified RCC before ablation. Postprocedure follow-up imaging was performed by contrast-enhanced computed tomography or magnetic resonance imaging. Results: Mean patient age was 66 years and 81% of patients were male. RCC subtypes included clear cell ( n =25), papillary ( n =12), and unspecified ( n =18) and Fuhrman grades 1, 2, 3, and ungraded in 15, 25, 1, and 14 patients, respectively. The mean tumor diameter was 2.6 cm (range 0.8–4.0 cm). Six low-grade complications were recorded during 53 (11.3%) procedures: five Clavien Grade 1 (urine retention, fluid overload, and atrial fibrillation) and one Grade 2 (hemorrhage requiring transfusion). The postprocedure estimated glomerular filtration rate was not significantly changed from preprocedure levels (median: −1.1%, p =0.10). Median follow-up was 8 months (interquartile range [IQR] 5–18.25) with 0/38 (0%) patients demonstrating evidence of local recurrence or metastasis during surveillance imaging. Conclusions: Use of a high-powered MW ablation system for the treatment of T1a RCC is feasible, safe, and efficacious with short-term follow-up. A longer follow-up is warranted to evaluate oncologic outcomes.