Harras Zaid

MP72-01 PREDICTING RENAL CELL CARCINOMA PROGRESSION AFTER SURGERY

INTRODUCTION AND OBJECTIVES: Multiple algorithms exist for the prediction of progression after surgical treatment of localized renal cell carcinoma (RCC); however, most are limited to clear cell (ccRCC) only, and have not been updated with contemporary pathologic assessment. We therefore sought to develop predictive models for progression in ccRCC, papillary RCC (papRCC), and chromophobe RCC (chrRCC). METHODS: Binephric patients treated with radical or partial nephrectomy for sporadic, unilateral M0 ccRCC, papRCC, or chrRCC between 1980 and 2010 were identified. All patients had their pathology slides re-reviewed by one pathologist, blinded to patient outcome. Associations with time to progression (defined as local recurrence, distant metastasis, or death from RCC) were evaluated with multivariable Cox proportional hazards regression with stepwise selection using a 500sample bootstrap resampling approach. RESULTS: In total, 3,549 patients were identified: 2,726 (76.8%) with ccRCC, 601 (16.9%) with papRCC, and 222 (6.3%) with chrRCC. For patients with ccRCC, median follow-up was 9.9 years during which time 862 progressed. Features independently associated with ccRCC progression were constitutional symptoms, grade, coagulative necrosis, sarcomatoid differentiation, tumor size, fat invasion, tumor thrombus level, extension beyond Gerota’s fascia, and pN classification. The c-index of this model was 0.83. For papRCC patients, median follow-up was 10.3 years during which time 66 had progressed. Features associated with papRCC progression were grade, fat invasion, and tumor thrombus level, resulting in a c-index of 0.77. For chrRCC patients, median follow-up was 9.1 years during which time 35 had progressed. Features associated with progression included sarcomatoid differentiation, fat invasion, and pN classification, resulting in a c-index of 0.77. Predicted 10-year progression-free survivals for patients without any risk factors were 96%, 96%, and 91% for ccRCC, papRCC, and chrRCC, respectively. CONCLUSIONS: Using routine clinical and pathologic data, we generated 3 histology-specific predictive models for progression after surgical management of RCC. These models have excellent discrimination and may prove important in patient counseling and follow-up planning after surgical intervention. Source of Funding: None

MP100-06 CRYOABLATION OF CT1 RENAL MASSES IN “HEALTHIER” PATIENTS: EARLY OUTCOMES FROM MAYO CLINIC

INTRODUCTION AND OBJECTIVES: 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 “healthier” patients, who are otherwise candidates for surgery, has been limited. Here, we reviewed our institutional experience in such 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%) met inclusion criteria. Median age of this cohort was 57 years (IQR 52-62), with preablation eGFR of 75.6 (IQR 69.0-86.3) (Table). 14 (32.6%), 19 (44.2%), and 10 (23.2%) patients reported zero, one, or multiple prior abdominalpelvic surgeries, respectively. Five patients (11.6%) had a prior partial nephrectomy. 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 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 healthier patients, particularly those with challenging surgical anatomy or prior renal surgery, warrants further study.