medwireNews: Elevated levels of circulating tumor (ct)DNA are associated with significantly worse disease-free survival (DFS) in patients with early, locally advanced, or metastatic breast cancer, indicates a meta-analysis.
“These findings suggest that monitoring ctDNA levels in breast cancer has the potential to gauge response to treatment and aid in early detection of disease progression or recurrence,” write the researchers in JAMA Network Open.
They collated data on 739 participants of eight studies that measured ctDNA and DFS, progression-free survival (PFS), or relapse-free survival (RFS); five studies reported on patients with early-stage breast cancer and three on those with locally advanced or metastatic disease.
Carolyn Cullinane, from Cork University Hospital in Ireland, and colleagues identified a significant association between elevated ctDNA levels and reduced DFS, where the definition of DFS included PFS and RFS, with a hazard ratio (HR) of 4.44.
The results remained consistent when participants were grouped by disease stage, at significant HRs of 8.32 and 1.91 for those with early-stage and locally advanced or metastatic disease, respectively.
There was also a significant correlation between elevated ctDNA in samples collected prior to initiating oncologic or surgical therapy and worse DFS (HR=3.30; five studies). By contrast, although there was a trend toward reduced DFS among participants with raised ctDNA levels in post-treatment samples (three studies), the association did not reach statistical significance (HR=8.17).
The study authors report that heterogeneity in the included studies was “statistically significant” for the overall meta-analysis and for the subgroup analysis of post-treatment samples; for the remaining analyses, there was “no considerable heterogeneity between the studies.”
They also highlight other limitations, such as the fact that “all of the relevant literature pertaining to this subject could not be included in the analysis owing to lack of data available,” despite efforts to communicate with the authors.
And the team concludes that “[a] standardized technique needs to be established in order to introduce ctDNA analysis into routine clinical practice.”
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