Purpose Renal cell carcinoma with sarcomatoid dedifferentiation (sRCC) is an aggressive malignancy associated with a poor prognosis. While existing literature focuses on patients presenting with metastatic disease, characteristics and outcomes for patients with localized disease are not well described. We aimed to evaluate post-nephrectomy characteristics, outcomes, and predictors of survival in patients with sRCC who presented with clinically localized disease. Patients and Methods An IRB-approved review from 1986–2011 identified 77 patients who presented with clinically localized disease, underwent nephrectomy and had sRCC in their primary kidney tumor. Clinical and pathologic variables were captured for each patient. Overall survival (OS) and recurrence-free survival (RFS) were calculated for all patients and those who had no evidence of disease (NED) following nephrectomy, respectively. Comparisons were made with categorical groupings in proportional hazards regression models for univariable and multivariable analyses. Results OS for the entire cohort (N=77) at 2 years was 50%. A total of 56 (77%) patients of the 73 who were NED following nephrectomy experienced a recurrence, with a median time to recurrence of 26.2 months. On multivariable analysis, tumor stage, pathologically positive lymph nodes, and year of nephrectomy were significant predictors of both OS and RFS. Limitations include the retrospective nature of this study and relatively small sample size. Conclusions Long-term survival for patients with sRCC, even in clinically localized disease is poor. Aggressive surveillance of those who are NED following nephrectomy is essential and further prospective studies evaluating the benefit of adjuvant systemic therapies in this cohort are warranted.

ObjectivesTo evaluate the feasibility, safety, pathological, radiological and functional outcomes of salvage surgery after previous renal mass ablation therapy. Patients and MethodsAfter institutional review board approval, we reviewed our renal tumour database, and described the characteristics and outcomes of patients who experienced a local recurrence after energy ablation for renal masses and underwent salvage surgical therapy. ResultsA total of 14 patients fit the inclusion criteria. The median (interquartile range [IQR]) age was 65 (59-77) years, with a median (IQR) Charlson comorbidity index score of 2 (0.75-3.00). Three patients had a solitary kidney. Seven patients received their ablation therapies at an outside institution. Ten patients had undergone percutaneous radiofrequency ablation, three percutaneous cryoablation and one laparoscopic cryoablation. The median (IQR) R.E.N.A.L. nephrometry score at time of surgery was 7 (5-9), while the median (IQR) time from ablation to surgery was 26.5 (16.3-39.3) months. Of the 14 patients, 11 underwent partial nephrectomy and three underwent planned radical nephrectomy. The median (IQR) surgery time was 203 (177-265) min and the median length of stay was 5.5 days. There was one microscopic positive surgical margin. The median tumour size at final pathology was 3.1 cm. In all, 13 patients had renal cell carcinoma and one had no tumour present. Nine were pT1a, 1 pT1b, 2 pT3a, and 1 pT3b tumours. There were four Clavien grade III complications in four patients. The median preoperative estimated glomerular filtration rate (eGFR) and the eGFR at last follow-up were 66 and 66 mL/min/1.73 m 2 . There had been no deaths by the median (IQR) follow-up of 26.5 (10.5-49.5) months. ConclusionsPatients who have undergone previous renal ablation therapy can be salvaged with partial or radical nephrectomy with good intermediate-term outcomes. These procedures may be associated with a high rate of adverse events. Longer follow-up is necessary.

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401 Background: sRCC is an aggressive subset of renal cell carcinomas that is associated with poor prognosis. We describe clinical and pathological characteristics and outcomes of the largest single-institutional cohort of patients with sRCC who underwent nephrectomy. Methods: Data were collected from 1986 to 2011 for patients identified as having sRCC. 221 patients with complete data who underwent a radical or partial nephrectomy and had a sarcomatoid component in the primary kidney tumor were included in the analysis. Clinical and pathologic variables were reviewed and Kaplan-Meier curves were used to compare differences in overall survival. Results: Mean age at diagnosis was 57 years and median tumor size was 11 cm (range 1.5-27.0 cm). 93% of patients were symptomatic at presentation and 96% had an ECOG performance status of 0 or 1. 12 patients had a preoperative biopsy that showed sRCC. 75% of patients were pT3 or higher at time of nephrectomy and 69% presented with metastatic disease. Of these, 11.8% had radiographic evidence of regional nodal involvement alone and 88.2% had distant metastatic disease. The associated epithelial component was clear cell in 72% of the patients, papillary in 12.7% and chromophobe in 3.1%. 29 patients received presurgical systemic therapy, while 161 patients received postoperative systemic therapy. During a median follow-up of 20.5 months, 187 patients (84%) died. Overall survival for the entire cohort at 1 year was 48%. Overall 1-, 2-, and 3-year survival rates for patients with metastatic disease at presentation versus no metastatic disease were 36, 20, and 16% versus 74, 51, and 44% respectively (p < 0.001). Patients with clear cell RCC epithelial component had a survival advantage over those with non-clear cell components with 1-, 2-, and 3-year survival rates of 52, 34, and 31% versus 38, 19, and 12% (p = 0.0057). Conclusions: The majority of patients with sRCC who underwent nephrectomy present with metastatic disease and outcomes are dismal despite surgical intervention and multimodal therapy. Overall survival is better for patients who present without metastatic disease and have clear cell histology at time of nephrectomy.