Liquid biopsy improves MRI accuracy in breast cancer patients: Study

Italy: Liquid biopsy addition to MRI may improve the ability to measure treatment response of breast cancer, finds a recent study. The study findings were presented at the American Association for Cancer Research (AACR) annual meeting. 

According to the study, in patients treated for localized breast cancer, measurement of plasma cell-free DNA (cfDNA) after chemotherapy and before surgery has the potential to improve MRI accuracy alone. This suggests a potential role of liquid biopsy for bolstering MRI which has suboptimal accuracy for this clinical use. There is a need for further and prospective evaluation.

Liquid biopsy's potential for improving the sensitivity of imaging has been an important area of cancer research in recent years.

Typically today, sentinel lymph node biopsy is performed to assess axillary node response after chemotherapy and is followed by lymph node dissection in those who do not have a complete response. A more accurate noninvasive method for gauging complete response and for monitoring could save some patients from the need for sentinel lymph node biopsy, the researchers noted.

To address the limitations of MRI as a presurgical guiding tool, Francesco Ravera, a fellow in the department of internal medicine at the University of Genoa in Italy, and colleagues, sought to assess if cfDNA testing could help assess pathological complete response following chemotherapy.

For the purpose, the researchers performed a retrospective study in which the researchers analyzed blood from breast cancer patients who had undergone neoadjuvant anthracycline/taxane chemotherapy, with samples available from the time of diagnosis and after treatment. The samples were profiled based on histopathological analysis, a DNA integrity index was developed as a measure of the degree of fragmentation of cells in the blood associated with responders and nonresponders.

The cfDNA integrity index was evaluated in 38 patients, of whom 11 had a pathological complete response after neoadjuvant chemotherapy treatment. Researchers assessed MRI and the cfDNA integrity index individually, as well as the accuracy of the two tests together when the results were in agreement.

Agreement of MRI and cfDNA results yielded a positive predictive value of 87.5% and a negative predictive value of 94.7%.