Schmit, Grant D.

Radiologists play a key role in the management of renal masses, and it is important to understand the nonsurgical treatment options for solid renal masses, typical imaging findings after treatment, common complications, and methods to avoid pitfalls.

610 Background: Personalized treatment for clinical T1 renal cortical masses (RCMs) should account for competing risks related to tumor and patient characteristics. Using a contemporary multi-institutional cohort, we developed treatment-specific prediction models for cancer-specific mortality (CSM), other-cause mortality (OCM), and 90-day complication rates for patients managed with surgery, thermal ablation (TA), and active surveillance (AS). Methods: Preoperative clinical and radiological features were collected for eligible patients aged 18-91 years treated at four academic centers from 2000-2016. Prediction models used competing risks regressions for CSM and OCM and logistic regressions for 90-day Clavien >3 complications, adjusting for tumor size as well as patient age, sex, ECOG performance status (PS), and Charlson comorbidity index (CCI). Predictions accounted for missing data using multiple imputation. Results: After excluding 25 patients with no follow-up, the cohort included 4995 patients treated with radical nephrectomy (RN, n=1270), partial nephrectomy (PN, n=2842), thermal ablation (n=479), or active surveillance (n=404). Median follow-up was 5.1 years (IQR 2.5-8.5). Predictions from the fitted model are shown in an online calculator ( https://rgulati.shinyapps.io/rcc-risk-calculator ). To illustrate the use of this calculator for a specific patient, a 70-year-old female with a 5.5 cm RCM, PS of 2, and CCI of 3 has a predicted 5-year CSM of 4-7% across treatments, 5-year OCM of 34-49%, and 90-day risk of Clavien ≥3 complications of 4%, 10%, and 6% for RN, PN, and TA respectively. Conclusions: Personalized treatment selection for cT1 RCM is challenging. We present a competing risk calculator that incorporates pretreatment features to quantify competing causes of mortality and treatment-associated complications. Pending validation, this tool may be used in clinical practice to provide patients with estimated individualized treatment-specific probabilities of competing causes of death and complication risks to facilitate shared decision-making.

Objectives To evaluate the peri‐operative and renal functional outcomes of patients undergoing synchronous bilateral partial nephrectomy (PN) or percutaneous cryoablation (PCA). Patients and Methods We retrospectively reviewed our institutional nephrectomy and renal mass ablation registries to identify all patients with synchronous bilateral renal masses who underwent simultaneous bilateral PN ( n = 76) or PCA ( n = 13) between 1974 and 2013. Changes in estimated glomerular filtration rate (eGFR) as well as peri‐operative complications are descriptively reported for each procedure. Results The number of treated renal masses in the 76 patients in the PN group and the 13 patients in the PCA group was 249 and 28, respectively. The median (interquartile range [IQR]) age at treatment was 62 (50, 71) years for the PN group and 67 (56, 72) for the PCA group. The median (IQR) maximum tumour sizes were 4.6 (3.4, 6.5) cm and 2.6 (2.4, 3.2) cm for the PN and PCA groups, respectively. The median (IQR) length of hospital stay was 7 (5, 8) days for the PN group and 1 (1, 10) days for the PCA group. The median (IQR) change in eGFR from baseline to discharge was −32 (−46, −15)% for the PN group and −17% (−33, −3) for the PCA group. By 3 months, median (IQR) renal function improved, with changes of −9 (−19, 0)% and −8 (−11, 15)%, respectively, compared with baseline. No patient in either group required renal replacement therapy in the peri‐operative period. Early postoperative complications (within 30 days) occurred in 16 patients (21.6%) in the PN and four patients in the PCA group. In particular, angioembolization for bleeding was required in the postoperative period in two patients (2.7%) in the PN and one patient in the PCA group. Conclusions Our experience suggests that synchronous bilateral PN or PCA are feasible treatment options for select patients presenting with bilateral renal masses. In select cases, both approaches appear to have reasonable rates of peri‐operative complications and effects on renal function.

SummaryObjectiveEvidence on the diagnostic performance of adrenal imaging is limited. We aimed to assess the diagnostic performance of unenhanced computed tomography (CT) and 18F‐fluorodeoxyglucose (18FDG) positron emission tomography (PET)/CT imaging in a high‐risk population for adrenal malignancy using an optimal reference standard.DesignRetrospective cohort study.MethodsImaging studies of patients with adrenal nodules who underwent adrenal biopsy and/or adrenalectomy between 1994 and 2014 were reviewed and compared to the reference standard of histology. Eighty % of patients presented with known or suspected extra‐adrenal malignancy.ResultsUnenhanced abdominal CT was performed in 353 patients with adrenal lesions; median size was 3 (0.7‐15) cm and median radiodensity was 33 (−21‐78) Hounsfield units (HU). Radiodensity of >10 HU diagnosed malignancy with a sensitivity of 100%, specificity of 33%, positive predictive value (PPV) of 72% and negative predictive value (NPV) of 100%. 18FDG‐PET/CT was performed in 89 patients; median tumour size was 2.1 (0.7‐9.2) cm. Maximum standardized uptake (SUV max) was higher in malignant lesions when compared to benign lesions (median=10 [2.3‐29.4] vs 3.7 [1.4‐24.5], respectively, P<.0001). Similarly, median SUV max lesion to SUV max liver ratio (ALR) in malignant lesions was higher than in benign lesions (median=3 [0.74‐13.4] vs 1.2 [0.5‐6.6], respectively, P<.0001). 18FDG‐PET/CT ALR >1.8 diagnosed malignancy with a sensitivity of 87%, specificity of 84%, PPV of 85% and NPV of 86%.ConclusionNoncontract CT radiodensity of ≤10 HU excludes malignancy even in a high‐risk population. For indeterminate adrenal lesions, given a superior specificity, 18FDG‐PET/CT could be considered as a second stage imaging study.

Objectives To compare renal functional changes after percutaneous cryoablation ( PCA ) or partial nephrectomy ( PN ). Patients and Methods Patients who underwent PCA or PN for a solitary renal mass at a single institution were identified (2003–2013). Estimated glomerular filtration rates ( eGFR s) were calculated at baseline, discharge, and at the 3‐month follow‐up using the Chronic Kidney Disease Epidemiology Collaboration equation. Changes in renal function were compared between groups using 1:1 propensity score ( PS ) matching, adjustment for PS quintile, and inverse probability weighting ( IPW ). Results There were 2 040 procedures available for the PS analyses, including 448 PCA and 1 592 PN . After PS adjustments, there were no significant differences in baseline clinical features between PCA and PN patients. In the PS ‐matched analysis, the change in eGFR from baseline to discharge for PCA and PN patients was −3.1 and −1.1 mL /min/1.73 m 2 , respectively ( P = 0.038), with percentage changes of −4.5% and 0% respectively ( P = 0.006). From baseline to the 3‐month follow‐up, the absolute change in eGFR for PCA and PN patients was −4.3 and −2.1 mL /min/1.73 m 2 , respectively ( P = 0.008), and the percentage change was −6.1% and −2.4% respectively ( P = 0.005). Similar results were obtained after adjusting for PS quintiles and in the IPW analysis. Importantly, the rate of chronic kidney disease stage progression at the 3‐month follow‐up was similar between the groups (21% vs 18%). Conclusions Our results confirm that both PCA and PN have a minor impact on renal function. While we observed a statistically greater decline in eGFR after PCA compared with PN , both approaches result in excellent preservation of renal function.

433 Background: Current guidelines suggest that percutaneous thermal ablation (PTA) can be utilized in those with significant comorbidity who are unable to tolerate surgery (radical or partial nephrectomy). However, the use of PTA in healthy patients, who are otherwise candidates for surgery, has been limited. Here, we reviewed our institutional experience in healthy patients electing to undergo PTA, specifically cryoablation. Methods: We identified patients ≤65 years undergoing percutaneous cryoablation for solitary, non-metastatic renal masses <7cm (cT1). We further limited our cohort to patients with an ASA score of 1 or 2, and in whom pre-operative eGFR was >60. Clincopathologic characteristics and recurrence patterns (local recurrence within the kidney versus metastatic disease) were evaluated. Results: Between March 2003 and December 2015, 705 patients underwent cryoablation, of whom 43 (6.1%) were deemed to be “healthy”. Median age of this cohort was 57 years (IQR 52−62), with pre-ablation eGFR of 75.6 (IQR 69.0-86.3). Seven patients (16.3%) had a prior partial nephrectomy, and 5 (11.6%) had a solitary kidney. The majority (40, 93.0%) of ablated masses were cT1a, with 3 (7.0%) being cT1b. Median tumor size was 2.0 cm. 27 masses (63.7%) were biopsy-proven renal cell carcinoma (RCC) and 6 (13.6%) were benign; histology was unknown in 10 (22.7%). Follow-up imaging was available for 37 patients. Median radiological follow-up was 22 months (IQR 9-42), during which time 2 patients developed metastatic disease and 1 developed local recurrence; all events were in patients with biopsy-proven RCC. No patients died from RCC during this time period. Conclusions: In this single institution cohort of “healthier” patients with cT1 solitary renal masses, cryoablation offered reasonable short term oncologic control. While longer follow-up data are needed to evaluate for durability, cryoablation in healthy patients, particularly those with challenging surgical anatomy, warrants further study.