Spontaneous changes in tumour cell dissemination to bone marrow in colorectal cancer.

Aim: The study aimed to evaluate the incidence of disseminated tumour cells (DTCs) in bone marrow (BM) preoperatively and during follow up and to correlate these with established risk factors in patients with colorectal cancer.

Method: We prospectively studied BM in 57 patients using the anti-cytokeratin antibody A45-B/B3.

Results: The overall detection rate of DTCs was 23% with a similar detection rate through all stages of the disease. No significant association was found between the presence of DTCs and clinicopathological parameters. After a median follow up of 35.4 months, no differences were found in relapse and overall survival between patients with and without DTC preoperatively. In 31 of 45 patients with local disease, we performed a follow-up BM examination after 1 year. In 26% of the patients, the BM status had changed as compared with the preoperative finding.

Conclusion: This is the first study to report the follow up of DTC in BM in colorectal cancer using the A45-B/B3 antibody. The presence of tumour cells in the preoperative BM had no impact on outcome. The BM status had changed after 12 months in a quarter of patients.