Conference Coverage

CTC matches MD judgment for mBC therapeutic choice



SAN ANTONIO – For patients with estrogen-receptor positive, HER2-negative metastatic breast cancer, the use of circulating tumor cell (CTC) counts can help clinicians decide with confidence between ordering first-line hormonal therapy or chemotherapy, investigators say.

In the phase 3 STIC CTC trial, patients were randomly assigned to receive therapy based on either the clinician’s judgment of the best course of therapy for each patient; or on the CTC count with a cutoff of less than 5 CT/7.5 mL, indicating hormonal therapy; and 5 CTC/7.5 mL or above, indicating higher-risk disease requiring chemotherapy. In the clinician’s choice arm, the CTC reading was recorded but not implemented, and in the CTC arm, the clinician’s choice was dismissed.

The trial met its primary noninferiority endpoint, indicating that, in the overall population, CTC counts can provide clinician’s with confidence in the therapeutic choice, said Francois-Clement Bidard, MD, PhD, from Institut Curie in Paris.

In a video interview, Dr. Bidard discussed the trial findings, including the provocative exploratory analysis suggesting that, in patients in whom there is discordance between CTC and clinician choice, chemotherapy may be a better therapeutic option.

The study was funded by the National Cancer Institute of France, Institut Curie, and Menarini Silicon Biosystems. Dr. Bidard disclosed research funding and travel grants from Menarini.

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