Purpose: We tested the hypothesis that the presence of circulating tumor cells (CTCs) is a negative prognostic factor in patients with stage I-III colorectal cancer (CRC).

Patients and methods: This was a prospective study to test for the presence of CTCs in peripheral blood and bone marrow in 182 colorectal cancer patients at the time of surgery and one month after surgery using real-time RT-PCR for carcinoembryonic antigen (CEA) and cytokeratin 20 (CK20).

Results: Overall, 24 of 147 (16.3%) stage I-III CRC patients developed recurrence/metastasis postoperatively in a mean follow-up period of 22.9 months. There was no correlation between CTCs and conventional clinical pathological features. In total, 51.7% of patients were CTC positive detected in peripheral blood and/or bone marrow at the time of surgery using CEA and/or CK20 and 47% of patients were CTC positive one month after surgery. At surgery, CTC positive patients measured as CEA mRNA copy number in peripheral blood showed significantly poorer disease-free survival (DFS) (p=0.05). One month after surgery, both increased above threshold CEA and/or CK20 mRNA levels in bone marrow and CK20 mRNA level in blood correlated with shorter DFS (p=0.005, resp. p=0.0035). In addition, systemic increase in CEA gene expression, even if the values remained below cut-off threshold also correlated with poorer DFS (p=0.005).

Conclusion: Detection of CTCs at surgery and/or one month after surgery is an independent negative prognostic factor for relapsing-free survival in stage I-III colorectal cancer.

Acknowledgments of research support: This study was supported by grants MSM 151100001, IGA MZCR NR/7804-5 and IGA MZCR NR/9076.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 842.