8P - Dismantling the role of liquid biopsy in predicting outcome of patients with early-stage breast cancer following neoadjuvant therapy: A systematic review

Background

Numerous studies have suggested that the dynamics of ctDNA during neoadjuvant therapy in early breast cancer have consequences for prognosis. Still, each study's small number of participants prevents drawing firm conclusions. We aimed to determine the predictive value of liquid biopsy in predicting the outcome of patients with early-stage breast cancer following neoadjuvant therapy.

Methods

Each author searched PubMed, EMBASE, and EuroPMC databases from inception until 5 June 2022. We conducted this study according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. The eligible studies must have the following inclusion criteria: Early-stage breast cancer patients receiving neoadjuvant systemic therapy of any kind, an observational study (prospective or retrospective), or randomized control trials, and have documented serial collection of ctDNA and outcome data of interest. The impact of ctDNA detection at several time intervals on relapse-free survival and overall survival was the primary key outcome of the current study. In terms of data extraction, we collected the following from eligible studies: author, year of publication, number of patients, method of ctDNA analysis, RFS, and OS. We applied the Cochrane Collaboration's Risk of Bias tool to thoroughly evaluate the risk of bias in all qualifying publications.

Results

11 were counted in the meta-analysis since they satisfied the qualifying requirements. ctDNA detection significantly decreased both RFS (HR of 4.21 [1.29, 13.81] and 5.90 [2.86, 12.15], respectively) and OS (HR 19.13 [6.90, 53.03] and HR 4.00 [1.90, 8.41], respectively), both at baseline and after the end of neoadjuvant therapy. 8 and 3 studies were good and moderate in quality, respectively.

Conclusions

Our meta-analysis showed that long-term outcomes in early breast cancer were associated with the presence of ctDNA at baseline and after neoadjuvant therapy. Harmonization of methodologies is crucial in forging ahead as it is currently unknown how the analysis method affects the prognostic importance of ctDNA. Further studies need to be conducted in the near future with a standardized analysis method of ctDNA.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

Jeremiah Hilkiah Wijaya.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.