Very late relapse metastatic renal cell carcinoma: Characteristics and outcomes of patients with a disease-free interval of greater than 10 years.

Abstract

541 Background: Late relapse of renal cell carcinoma (RCC), or presentation with metastatic disease after a disease free interval of >5 years, is a known behavior of RCC. Recent studies have concluded that late relapse RCC is associated with favorable patient and tumor characteristics as well as an improved response to targeted therapy (TT) when compared to early relapse patients. Less studied are patients who relapse very late, with a disease free interval >10 years. We evaluated the clinical characteristics, response to TT and outcomes of this unique population. Methods: We collected data on consecutive patients with metastatic RCC who had disease recurrence >10 years after nephrectomy. Outcomes were tabulated using basic statistical techniques; adverse events were graded using CTCAE v4.0 and treatment response graded using RECIST 1.1. Results: Among 720 RCC patients treated with nephrectomy, we identified 8 who developed recurrent metastatic disease after a >10 year disease free interval (median: 16.7 years; range: 11.7-29.0). All patients presented with clear cell histology; 88% favorable IMDC and MSKCC risk subgroups. All patients presented with multiple metastases, with the most common sites being lung and bone, while unusual sites such as soft tissue, pancreas and adrenal were also detected. Median time on first-line TT was 20.1 months; 4, 3 and 1 patient received pazopanib (best response: PR), sunitinib (best response: SD) and cytokine (best response: PD) as first-line therapy, respectively. The median number of sequential TT received was 2 (range: 1-4). Four patients died, median OS was 46.6 months (range: 9.8-129), 3 year OS rate was 63%. Common adverse events to TT were fatigue (88%), anorexia (38%) and diarrhea (50%), 94% grade 1/2. Conclusions: Patients are at life-long risk of recurrence after resection of localized RCC as it is possible for metastases to present >10 years after resection. Patients in our study had relatively large metastatic burden and a wide distribution of metastatic sites, insights that may be useful clinically during surveillance. Our cohort demonstrated favorable prognostic features and outcomes when compared to historical controls.