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CTCs Breast Cancer — SCE Medical Oncology MCQ

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ModerateBreast CancerCTCs Breast CancerSCE Medical Oncology

A 58-year-old woman with breast cancer asks about the role of circulating tumour cells (CTCs) in her management. Her CTC count is 8 per 7.5 mL blood (elevated). What is the clinical significance?

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Correct answer: D — Elevated CTCs (≥5/7.5 mL in metastatic breast cancer) are an independent adverse prognostic marker for PFS and OS — however, CTC count is NOT currently recommended for routine treatment decisions

CTC enumeration (CellSearch) is FDA-cleared for prognosis in metastatic breast cancer. ≥5 CTCs/7.5 mL is associated with significantly worse PFS and OS. However, the SWOG S0500 trial showed that changing therapy based on persistently elevated CTCs did NOT improve outcomes compared with maintaining the current regimen. Therefore, CTCs are prognostic but not currently predictive for treatment decisions. Emerging CTC-based technologies (CTC-derived molecular profiling, CTC cultures) may have future clinical utility.

Reference: https://www.nice.org.uk/guidance/conditions-and-diseases/cancer