AB003. SOH22ABS024. Assessment of preoperative and postoperative circulating cell free tumour DNA (ctDNA) can predict risk of recurrence in patients with nonmetastatic breast cancer
Clinical Breast Session

AB003. SOH22ABS024. Assessment of preoperative and postoperative circulating cell free tumour DNA (ctDNA) can predict risk of recurrence in patients with nonmetastatic breast cancer

Fara Hassan1,2, Jiang Huai Wang2, Donal Peter O’Leary1,2, Carolyn Cullinane1,2, Mark Corrigan1,3, Henry Paul Redmond1,2

1Department of Breast Surgery, Cork University Hospital, Cork, Ireland; 2Department of Breast Surgery, University College Cork, Cork, Ireland; 3SURGUVANT Research Lab, University College Cork, Cork, Ireland

Background: Postoperative risk stratification in nonmetastatic breast cancer presents ongoing challenges. Circulating tumour DNA (ctDNA) contains tumour-specific gene mutations detectable in the blood of patients with breast cancer. In this study, we investigated the feasibility of High-Resolution Melting (HRM) PCR technology for detecting PIK3CA mutations in preoperative and postoperative blood samples and its prognostic significance in patients with breast cancer.

Methods: Preoperative and postoperative blood samples were analysed from 63 patients with breast cancer who underwent curative surgery. HRM PCR was used to identify PIK3CA mutations at exon 9 and 20 in ctDNA. HRM assays were developed using specifically designed primers and genomic DNA isolated either from cell lines or ctDNA. Melting curve analyses and mutation analyses were performed on the Light Cycler PCR platform.

Results: In a cohort of 63 patients [age, median interquartile range (IQR), 52 years (26–84 years)], with a median follow-up of 60 months (IQR, 3–60 months), 26 (41.2%) and 22 (35%) patients had detectable PIK3CA mutations in ctDNA preoperatively and postoperatively, respectively. Detectable PIK3CA mutations in postoperative ctDNA [hazard ratio (HR): 4.95, 95% confidence interval (CI): 1.87–13.09, P=0.0003] was associated with inferior recurrence-free survival (RFS). ctDNA-based detection preceded clinical detection of recurrence (n=13,35%) in patients with positive metastasis with an average lead time of 16 months (range, 12–24 months)

Conclusions: Our study highlights the prognostic significance of ctDNA in preoperative and postoperative serum samples of patients with breast cancer. However, prospective studies are needed to assess the prognostic potential of ctDNA in patients with non-metastatic breast cancer.

Keywords: Circulating tumour DNA (ctDNA); breast cancer; preoperative period (preop); postoperative period (postop); recurrence

Acknowledgments

Funding: None.

Footnote

Conflicts of Interest: The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

doi: 10.21037/map-22-ab003
Cite this abstract as: Hassan F, Wang JH, O’Leary DP, Cullinane C, Corrigan M, Redmond HP. AB003. SOH22ABS024. Assessment of preoperative and postoperative circulating cell free tumour DNA (ctDNA) can predict risk of recurrence in patients with nonmetastatic breast cancer. Mesentery Peritoneum 2022;6:AB003.

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