Background: We assessed the distribution of site-specific metastases in patients with renal cell carcinoma (RCC) according to age. Moreover, we evaluated recommendations proposed by guidelines and focused specifically on bone and brain metastases.
Patients and methods: Patients with metastatic RCC (mRCC) were abstracted from the Nationwide Inpatient Sample (1998-2007). Age was stratified into four groups: <55, 55-64, 65-74 and ≥ 75 years. Cochran-Armitage trend test and multivariable logistic regression analysis tested the relationship between age and the rate of multiple metastatic sites. Finally, we examined the rates of brain or bone metastases according to the presence of other metastatic sites.
Results: In 11,157 mRCC patients, the rate of multiple metastatic sites decreased with increasing age (P < 0.001). This phenomenon was confirmed in patients with lung, bone, liver and brain metastases (all P ≤ 0.01). The rate of bone metastases was 10% in patients with exclusive abdominal metastases and 49% in patients with abdominal, thoracic and brain metastases. The rate of brain metastases was 2% in patients with exclusive abdominal metastases and 16% in patients with thoracic and bone metastases.
Conclusions: The proportion of patients with multiple metastatic sites is higher in young patients. The rates of bone (10%-49%) and brain (2%-16%) metastases are nonnegligible in mRCC patients.