Circulating Tumor Cells (CTCs) correlate with adverse prognosis in breast, colorectal, lung and prostate cancer patients. Little data is available for Renal Cell Carcinoma (RCC).
We designed a multicenter prospective observational study to assess the correlation between CTC counts and Progression Free Survival (PFS) in metastatic RCC patients treated with an anti-angiogenic tyrosine kinase inhibitor as a first-line regimen; Overall Survival (OS) and response were secondary objectives. CTC counts were enumerated by the Cellsearch® system at 4 time points: day 0 of treatment, day 28, day 56 and then at progression, or at 12 months in the absence of progression.
195 eligible patients with a median age of 69 years were treated with sunitinib (77.5%) or pazopanib (21%). At baseline, 46.7% of patients had 1 or more CTCs/mL (range, 1 to 263). Thirty patients had ≥ 3 CTCs, with a median PFS of 5.8 vs 15 months in the remaining patients (p = 0.002), HR = 1.99, independently of the International Metastatic RCC Database Consortium (IMDC) score at multivariate analysis (HR: 1.91, 95% CI: 1.16-3.14). Patients with ≥ 3 CTCs had a shorter estimated OS of 13.8 months vs 52.8 months in those with <3 CTCs (p = 0.003), HR = 1.99 (multivariate analysis HR: 1.67, 95% CI: 0.95-2.93). Baseline CTC counts did not correlate with response, as well as having CTC sequencing counts ≥ 1, 2, 3, 4 or 5.
We provide prospective evidence that the presence of 3 or more CTCs at baseline is associated with a significantly shorter PFS and OS in mRCC patients.
In this prospective study we evaluated whether the presence of circulating tumor cells (CTC) in the peripheral blood correlate with activity of first-line tyrosine kinase inhibitors in metastatic Renal Cell Carcinoma (RCC). We demonstrated that almost half of patients with metastatic RCC have at least one CTC in their blood and that those patients with ≥ 3 CTCs are at increased risk of early progressive disease and early death due to RCC. Studies incorporating CTC counts in the prognostic algorithms of metastatic RCC are warranted.

© AlphaMed Press 2021.