Enumeration of CTCs in Predicting Therapeutic Outcomes in Metastatic Breast Cancer
Posted: Friday, January 8, 2021
After about 1 month of treatment for metastatic breast cancer, circulating tumor cell (CTC) assessments strongly predicted overall survival, according to an extensive retrospective analysis. These data were presented by Wolfgang J. Janni, MD, PhD, of the University Hospital Ulm, Germany, at the 2020 San Antonio Breast Cancer Symposium on behalf of his colleagues (Abstract GS4-08).
“These results provide clinical validation of CTC monitoring as an early treatment response marker in advanced breast cancer and suggest the potential for clinical utility,” said Dr. Janni in a premeeting press conference. “It is also very reassuring that CTC dynamics predicted outcomes for all breast cancer subtypes.”
This team of researchers compiled a meta-analysis of peer-reviewed studies with data on repeated CTC assessments in patients with metastatic breast cancer. Information from 2,761 individual patients within 32 studies was obtained from study investigators. Data from baseline plus one follow-up CTC assessment after a median of 35 days were compared using log rank tests and Cox regressions.
There were 588 patients (21.3%) with no CTC at both time points (neg/neg), 236 (8.5%) with negative CTC at baseline and positive CTC at follow-up (neg/pos), 712 (25.8%) with positive CTC at baseline and negative at follow-up (pos/neg), and 1,225 (44.4%) with at least one CTC at baseline and follow-up (pos/pos). The median overall survival for the neg/neg group was 45.6 months, compared with 34.6 months for the pos/neg group, 26.2 months for the neg/pos group, and 17.6 months for the pos/pos group.
On subgroup analysis based on hormone receptor or HER2 status of the primary tumor, patients who saw a CTC decrease after treatment had better survival outcomes. Overall survival improved by 53% in patients with luminal-like breast cancers, 46% in patients with HER2-positive breast cancer, and 59% in patients with triple-negative breast cancer when CTC levels decreased. Further, patients with triple-negative breast cancer in the pos/pos group had a significantly shorter overall survival than those in the neg/neg group (hazard ratio = 2.99).
Disclosure: For a full list of authors’ disclosures, visit www.sabcs.org.