Age-stratified distribution of metastatic sites in bladder cancer: A population-based analysis

Abstract

Introduction: Urothelial carcinoma of the urinary bladder (UCUB) is the most common malignancy of the urinary tract. We examined the distribution of site-specific metastases in patients with UCUB according to age and we assessed contemporary recommendations proposed by guidelines with regard to distant metastases.Methods: Patients with metastatic UCUB (mUCUB) were abstracted from the Nationwide Inpatient Sample (1998-2007). Age was stratified into quartiles: ≤63, 64-72, 73-79 and ≥80 years. Cochran-Armitage trend test and multivariable logistic regression analysis tested the relationship between age and the rate of metastases. Finally, we identified patients at high risk of brain or bone metastases.Results: Within 7543 patients with mUCUB, 25%, 24%, 23%,19%, 18% and 3% had lymph node, bone, urinary, lung and liver metastases, respectively. Overall, the rate of concomitant metastases was 29%. The rate of multiple metastatic sites decreased with increasing age (p < 0.001). This was confirmed in patients with lung, bone, liver, urinary system and brain metastases (all p ≤ 0.04). The rate of bone metastases was 15.0% in patients with exclusive abdominal metastases and 40.0% in patients with abdominal, thoracic and brain metastases. The rate of brain metastases was 1% inpatients with exclusive abdominal metastases and 7% in patients with thoracic and bone metastases. Our findings are limited by the retrospective nature of the analyses.Conclusions: We report a higher number of concomitant metastatic sites in young UCUB patients. Bone metastases are frequent in all patient groups, whereas brain metastases are common in UCUB patients with thoracic and/or bone metastases.