Circulating Tumor Cells in Bladder and Upper Tract Urothelial Carcinoma - Expert Commentary

Circulating tumor cells (CTCs) are cancer cells shed from the tumor that enter the circulation. Isolating circulating tumor cells from urothelial carcinoma patients has several potential diagnostic, prognostic and predictive clinical applications but the available data has been inconclusive.

A recent meta-analysis published in the journal Oncotarget evaluated the clinical utility of CTCs in urothelial carcinoma of the urinary bladder and the upper urothelial tract. The investigators identified 30 published studies including a total of 2161 urothelial cancer patients to identify associations between CTC-positive status and clinical characteristics and outcomes.

The investigators identified significant correlation between CTC-positivity and clinical characteristics that reflect advanced disease. CTC positivity was associated with a higher tumor stage (≤ II vs III, IV) (OR = 4.60, 95% CI: 2.34–9.03), histological grade (I, II vs III) (OR = 2.91, 95% CI: 1.92–4.40), metastasis (OR = 5.12, 95% CI: 3.47–7.55) and regional lymph node metastasis (OR = 2.47, 95% CI: 1.75–3.49). CTC-positive patients also had worse overall survival (OS) (HR = 3.98, 95% CI: 2.20–7.21), progression/disease-free survival (PFS/DFS) (HR = 2.22, 95% CI: 1.80– 2.73) and cancer-specific survival (CSS) (HR = 5.18, 95% CI: 2.21–12.13). The investigators conducted a sensitivity analysis that showed that the pooled survival HRs were not skewed by any individual study. 

This important study is an excellent synthesis of the published data on CTCs in urothelial carcinoma. Prospective large studies that account for different patient characteristics, CTC isolation methods and disease subtypes are needed. 

Written By: Bishoy Faltas MD 

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Reference:
Zhang Z, Fan W, Deng Q, Tang S, Wang P, Xu P, Wang J, Yu M.The prognostic and diagnostic value of circulating tumor cells in bladder cancer and upper tract urothelial carcinoma: a meta-analysis of 30 published studies. Oncotarget. 2017 Jun 16. doi: 10.18632/oncotarget.18521. [Epub ahead of print]
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