A real-world comparison of circulating tumor cells in breast cancer from China: Novel device, CTC counts and its overall survival.

BACKGROUND: Both CellSearch and CellCollector have been accepted as the proper devices to capture CTC by domestic approval department. However, there is little article about the comparison between these two devices around the world. Herein, we conducted the real-world study to compare with these two devices and to re-verify the efficacy of CTC counts.

METHODS: Patients who meet the following points should be included in the analysis. 1. Female, aged 18 years or older; 2. Eastern Cooperative Oncology Group (ECOG) score 0-2; 3. With at least one measurable tumor lesion; 4. Clear immunohistochemistry result; 5. Accept at least one CTC test. Patients were excluded in the analysis if they had a history of malignant tumors, incomplete follow-up information.

RESULTS: 536 metastatic breast cancer patients who had been detected for CTC at least once by CellSearch or CellCollector were included in the analysis. CellCollector in vivo CTC detection technology has a higher detection rate than the CellSearch system (69.2% vs 57.4%, P = 0.009). However, the proportion of CTC≥5 detected by CellSearch was higher than CellCollector (37.4% vs 16.3%, P < 0.001). There was a statistically significant difference in overall survival of patients with CTC negative and CTC positive (mOS:49.8 months vs 26.9 months). After 4 weeks of treatment, when CTC decreased by more than 50%, there was a significant difference in survival between the two groups (40.1 months vs 25.8 months, HR = 0.588, 95% CI: 0.350-0.933). In addition, for HER2-positive patients, Patients with CTC HER2 positive had longer overall survival than patients with CTC HER2 negative (median OS: 26.7 months vs 17.3 month, HR = 0.528, 95% CI: 0.269-0.887).

CONCLUSIONS: Real-world data indicate that CTC is an independent prognostic factor, and CellCollector and CellSearch have their own advantages in CTC detection.