Variation in recurrence rate and overall survival (OS) outcomes by disease stage and incremental impact of time to recurrence on OS in localized renal cell carcinoma (RCC).

4543 Background: Prior research shows that post-nephrectomy recurrence is correlated with significantly increased mortality in patients (pts) with intermediate-high (int-high) risk and high risk RCC. However, no study has quantified the incremental OS associated with increased time to recurrence (ToR). Additionally, limited evidence is presented on the variation of recurrence rate and OS by stage of RCC. Methods: The SEER-Medicare database (2007–2016) was used in this retrospective observational study. Post-nephrectomy pts with newly diagnosed, int-high risk (pT2 N0 high grade, pT3 N0 any grade) or high-risk (pT4 N0 any grade, pT any N1 any grade) RCC were identified and stratified based on tumor stage and grade. Grade was defined based on Furhman grading system and was reported in SEER Registry. Post-nephrectomy recurrence free rates and OS by disease stage were described using Kaplan-Meier analyses. OS from nephrectomy in pts with recurrence vs pts without recurrence was compared by disease stage. Multivariable regression analysis was used to quantify the incremental OS associated with increased ToR post-nephrectomy in all pts with recurrence. Results: 643 pts met the inclusion criteria (269 with vs 374 without recurrence; median follow-up: 23 months). The mean age was 75.5 years (yrs), 61% male, and 86% white. Results presented in the table showed wide variance in 5-yr recurrence-free rate in int-high risk group (28%-63%) and indicated substantial risk of disease recurrence in all subgroups of int-high risk pts. Among those with T3 Grade 1-2, T3 Grade 3, and T3 Grade 4 disease, pts with recurrence had significantly higher risk of death than those without (all ps<0.05;). Results for pts with T2 and T4 disease were not presented due to small sample size. Multivariable regression analysis indicated that 1 additional yr of ToR was associated with 0.73 additional yrs (8.8 additional months) of OS post nephrectomy (95% CI: 0.40, 1.05 yrs; p<0.001). Conclusions: The non-trivial recurrence rates observed in pts with T3 Grade 1-2 and T3 Grade 3 RCC highlighted the substantial risk of recurrence and unmet needs in the int-high risk RCC patients. This study also confirms the incremental nature of the association of ToR and OS in patients with int-high and high risk localized RCC. These findings highlight the need for effective early intervention with adjuvant treatments in int-high and high risk post-nephrectomy RCC pts. [Table: see text]