Abstract

Background

Despite no radiological or pathological evidence of disease, about 25–50% of stage II–III colorectal cancer (CRC) and early-stage breast cancer (BC) patients are known to experience recurrence. The presence of circulating tumor cells (CTCs) with epithelial–mesenchymal transition (EMT) traits represents aggressive systemic disease. Through autonomous oncogenic activation, epithelial cells acquire invasive properties that enable metastasis. A high EMT score combined with immune checkpoint expression, such as PD-L1, may allow tumor cells to evade immune surveillance. Following curative-intent surgery and therapy, CTCs represent minimal cellular residual disease (MCRD) and serve as strong predictors of recurrence. In this study, we present an automated extracorporeal device designed to capture, analyze, and deplete CTCs for further clinical evaluation.

Methods

We retrospectively analyzed 66 patients, including stage II–III CRC patients (n = 41) and breast cancer patients (n = 25). Whole blood samples were processed to deplete CTCs using the OncoMetastat device. Among the CRC patients, 12 were female and 29 were male. The average age of BC and CRC patients was 53.6 and 58 years, respectively. The device consists of a spiral channel (127 × 85 × 5 mm; spiral span: 66 mm; width: 4 mm) 3D-printed using biocompatible resin and filled with anti-EpCAM antibody–conjugated glass beads (GB). The system includes a controller and a peristaltic pump that circulates blood in and out of the spiral channels. Vibrational energy induces motion in the glass beads to enhance cell capture. Hemolysis, protein binding, leukocyte adsorption, and CTC capture efficiency were evaluated. CTC capture efficiency was compared with the CDSCO-approved OncoDiscover CTC technology in India. Blood samples were pumped into the device and incubated with affinity-enriched glass beads for 30 minutes under constant vibration (200 Hz) to enhance CTC capture and prevent blood stagnation. CTCs were confirmed using CK18⁺, DAPI⁺, and CD45⁻ markers and analyzed using an automated fluorescence microscope.

Results

A total of 48 CTCs were detected in 58% (38/66) of patients. CTC positivity was slightly higher in breast cancer patients (60.0%) compared with CRC patients (56.1%). The mean CTC distribution was 0.73 overall, with CRC and BC both showing mean values of 0.73 and 0.72, respectively. The negative predictive value (NPV) was determined to be 0.86 (86%). Automated scanning demonstrated 100% efficiency in detecting CTCs. Low leukocyte adhesion was observed with anti-EpCAM–coated glass beads. White blood cell (WBC) counts varied by cancer type, with mean counts of 4.9 × 10⁶/mL for breast cancer and 3.9 × 10⁶/mL for colorectal cancer, both lower than healthy controls (6.9 × 10⁶/mL). Clinically insignificant hemolysis (<1%) and minimal protein binding (~1.5%) were observed in the spiral channel. Glass beads subjected to vibrational energy demonstrated enhanced CTC sequestration, achieving over 90% cell capture efficiency compared with vibration-free conditions.

Conclusions

This study demonstrates efficient CTC depletion in 66 CRC and breast cancer patients using an automated extracorporeal device. Early-stage CRC and BC patients with detectable CTCs may have a higher risk of developing distant metastasis. Therefore, following complete remission, the use of an extracorporeal device to deplete CTCs could potentially reduce the risk of metastatic progression.