Introduction:

The presence of brain metastases and bone metastases are generally understood to herald worsened prognosis following nephrectomy in patients with renal cell carcinoma (RCC). However, we sought to determine the effect of bone metastases on outcomes when already present at the time of cytoreductive radical nephrectomy (RN). 

Methods:

Large, multicenter, retrospective review of patients with metastatic RCC (mRCC) undergoing cytoreductive RN between the years 2004 and 2018. To isolate the effect of bone metastases (BM) on outcomes, all patients with brain metastases were excluded from analysis. Demographic, clinical variables, and outcomes were collected. Patients were sorted into low, medium, and high-risk groups based on MSKCC/Motzer Scoring Criteria for mRCC. Primary outcome was progression-free survival and secondary outcome was overall survival. Kaplan Meier analysis (KMA) as well as Cox regression analysis (MVA) were performed for primary and secondary outcomes. 

Results:

There were 124 patients included in the analysis. KMA showed no difference in PFS or OS at 5 yrs PFS (25.5 vs. 27.4, p=0.958) and OS (7.0 vs. 6.2, p=0.973) with presence BM vs without, respectively. When patients were stratified by low (n=30), intermediate (n=208) and high risk (n=123), there were differences seen in OS times (p=0.001). However, there was no significant difference in intermediate or high-risk patients with or without BM (Intermediate risk: OS, p=0.365; PFS, p=0.786) (High risk: OS, p=0.558; PFS, p=0.487). In MVA for all patients with variables age, sex, BMI, ECOG, pathologic upstaging, positive surgical margins, intra-operative complications and presence of bone mets, no variable was independently associated with PFS. MVA for OS with the same variables demonstrated positive surgical margins alone to be significantly associated with worsened survival (OR 2.030, p=0.005).  

Conclusion:

In patients with metastatic RCC undergoing cytoreductive nephrectomy, the presence of bone metastases does not independently affect survival or oncologic outcomes. While further validation is needed, the prognostic significance of bone metastases at time of cytoreductive nephrectomy may overall be less than previously thought.

Funding: N/A