Introduction:

As the use of cross-sectional imaging has become more widespread, the rate of incidentally detected small renal masses has increased, along with the utilization of partial nephrectomy (PN). Local recurrence (LR) following PN has been variably defined in the literature, including recurrence within the ipsilateral kidney or retroperitoneum, new ipsilateral tumor growth, and tumor recurrence within the PN bed. True LR within the PN bed is uncommon, with reported rates of 1-3% in the literature. To date, there is sparse literature examining oncologic outcomes following true tumor bed recurrence. Our study seeks to summarize true LR rates, define oncologic outcomes associated with LR, and to determine if there is an association of LR with metastasis-free and cancer-specific survival following PN for unilateral, sporadic, localized renal cell carcinoma (RCC).

Methods:

Following institutional review board approval, we identified 2,164 adults treated with PN for unilateral, sporadic, localized (M0) RCC between 2000 and 2019. Local recurrence was defined as new enhancing tumor growth within the PN bed on cross-sectional imaging (MRI or CT). Survival rates were estimated using the Kaplan-Meier method. Associations with distant metastases and death from RCC following PN were evaluated using Cox proportional hazards regression models and summarized with hazard ratios (HRs) and 95% confidence intervals (CIs). The association of LR with cancer-specific death was analyzed in the subset of patients with clear cell RCC alone after adjusting for tumor size, pT classification, and grade.

Results:

A total of 106 true LR were identified. LR-free survival is summarized in Table 1. Median time to LR was 3.3 years (IQR 1.7-5.1). Management of LR included 89 surgeries, 5 targeted therapy, 4 surveillance, 8 others. Forty-five patients died at a median of 3.5 years (IQR 1.6-5.3) following LR, including 26 from RCC at a median of 1.9 years (IQR 0.8-4.0). Median duration of post-recurrence follow-up for 61 patients alive at last follow-up was 5.1 years (IQR 2.3-9.1). Among 83 patients who remained M0 at LR, 26 subsequently developed distant metastases at a median of 1.5 years (IQR 0.3-2.4). Metastasis-free and cancer-specific survival rates following LR are summarized in Table 2. When analyzed as a time-dependent covariate, LR was associated with cancer-specific death (HR 12.45; 95% CI 6.65-23.31; p<0.001). When adjusting for distant metastases, association of LR with cancer-specific death was attenuated (HR 1.93; 95% CI1.07-3.50; p=0.03).

Conclusion:

Partial nephrectomy is an acceptable surgical option for localized RCC with low true LR rates. Although most LRs occur within the first few years following PN, recurrence after 5 years was noted in several patients, demonstrating the need for continued long-term surveillance. We found that true LR following PN is a rare event; however, our analysis demonstrates that LR is associated with death from RCC, even after adjusting for the development of distant metastasis. Our data provides the first evidence demonstrating the need for consideration of further intervention to prevent RCC-related death with true LR.

Funding: N/a