Prognostic significance of circulating tumor cells (CTCs) in Egyptian non-metastatic colorectal cancer patients: A comparative study for four different techniques of detection (Flowcytometry, CellSearch, Quantitative Real-time PCR and Cytomorphology)

Purpose: We assessed CTCs counts in NMCRC patients using four different techniques. Methods: CTCs were detected in 63 NMCRC patients, 40 benign bowel diseases (BBD) and 40 normal controls (NC) using, flow-cytometry (FCM), CellSearch (CS), cytomorphology and quantitative real time (qPCR) for CK19, MUC1, CD44, CD133, ALDH1 expression. Results were correlated to progression free (PFS) and overall (OS). Results: Positive CTCs (≥4 cells /7.5 mL blood) were detected in 50.8% (32/63) NMCRC by FCM and 7.5% (3/40) BBD (p <.001). CTCs were detected in 34/63 (54%) NMCRC, 4/40 (10%) BBD (p <.001) by CS. CK19, MUC1, CD44, CD133 and ALDH1 were expressed in 35 (55.6%), 29 (46.0%), 28 (44.4%), 26 (41.3%) and 25 (41.3%) cases of NMCRC. In BBD 4/40 (10%) cases expressed CK19, MUC1 and CD44, while 2/40 (5%) expressed CD133. Cytomorphology showed the lowest sensitivity (47.6%) and specificity (90%) for CTCs detection. The combined use of FCM or CS with CTCs-mRNA markers improved the sensitivity and specificity to 68.3%, and 95.0%; respectively. Positive CTCs and mRNA markers expression were significantly associated with shorter 5-yr PFS and OS. In multivariate analysis, CTCs mRNA markers were independent prognostic factors for PFS and OS. Conclusions: Enumeration of CTCs by FCM and RNA expression for specific colon cancer markers are comparable to CS regarding sensitivity and specificity. CTCs also represent novel therapeutic targets for NMCRC cases.