Experts have defined two subgroups of metastatic breast cancer (MBC) based on concentrations of circulating tumour cells (CTCs).
In the retrospective, pooled analysis of 2,436 MBC patients from 18 cohorts, a CTC threshold of 5 cells per 7.5 mL was used to stratify patients as Stage IVaggressive (≥5) or Stage IVindolent (
Stage IVindolent patients had longer median overall survival (OS) than those with Stage IVaggressive (36.3 vs 16.0 months; P<.0001 the same was seen when restricted to de novo mbc patients vs months p>
Patients with Stage IVindolent disease had significantly longer OS across all sub-types compared with the aggressive cohort: hormone receptor positive (40.7 vs 17.3; P<.0001 positive p and triple negative vs>
Results were similar, regardless of prior treatment or disease location.
“We strongly believe that the large data accumulated over the years and the new combined analysis of the large dataset included in this study strongly support the notion that CTCs enumeration should be used for prognostic stratification of MBC in two defined groups of patients identified as Stage IVindolent and Stage IVaggressive,” the authors said.
They recommend that this classification is used as a stratification factor in future prospective clinical trials.