Association of Circulating Tumor Cells and Tumor Molecular Profile With Clinical Outcomes in Patients With Previously Untreated Metastatic Colorectal Cancer: A Pooled Analysis of the Phase III VISNÚ-1 and Phase II VISNÚ-2 Randomized Trials.

Background: The bCTC count is a well-established prognostic biomarker in mCRC, as well as in other tumor types. The aim of this analysis was to evaluate the prognostic/predictive role of the bCTC count (≥3 vs. <3) in previously untreated mCRC.
Patients and Methods: The study involved 589 untreated mCRC patients included in the intention-to-treat population of 2 randomized clinical trials (phase III VISNU-1 [NCT01640405] and phase II VISNU-2 [NCT01640444] studies).
Results: Of the 589 patients, 349 (59.2%) had bCTC≥3 and 240 (40.7%) had bCTC<3. Multivariate analysis showed that the bCTC count is an independent prognostic factor for overall survival (OS) (HR 0.59, 95% CI 0.48-0.72; P = 0.000) and potential for progression-free survival (PFS) (P = 0.0549). Median OS was 32.9 and 19.5 months in patients with bCTC<3 and bCTC≥3 (P <0.001), respectively. This effect was also observed comparing OS in RASwt patients from both studies. Other prognostic factors were: ECOG-PS, primary tumor site, number of metastatic sites and surgery of the primary tumor. Median OS was lower for patients treated with anti-VEGF versus anti-EGFR (22.3 vs. 33.3 months, P <0.0001) while there were no significant differences in PFS according to the targeted treatment received.
Conclusion: This post-hoc analysis of 2 randomized studies confirms the poor prognosis of patients with bCTC≥3 but this is not associated with other adverse independent prognostic factors such as RAS/BRAF mutations.
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