Prognostic value of disseminated colorectal tumor cells in the liver: results of follow-up examinations.

BACKGROUND AND AIMS

Dissemination of tumor cells is an initial step in metastatic disease. Detection of disseminated tumor cells (DTC) in blood, bone marrow and lymph nodes has been associated with reduced disease-free survival, but to date there are no data for hepatic DTC. We investigated the prognostic relevance of hepatic DTC that are present in patients with colorectal cancer (CRC) at the time of surgery.

PATIENTS AND METHODS

In 121 patients with CRC clinically diagnosed for liver metastasis by ultrasound, CT, and exploration during surgery DNA from liver biopsy specimens obtained during surgery was examined by a PCR-RFLP assay for K-ras mutations as a marker for DTC. At the time of surgery 54 of the 121 were mutated in K-ras codons 12 or 13. After a median follow-up of 405 days all survivors were reevaluated by ultrasound/CT.

RESULTS

Patients with a K-ras mutation in their primary tumor had a significantly lower probability of survival and higher risk of harboring a synchronous second colorectal carcinoma than patients with a K-ras wild-type tumor. Based on specimens taken intraoperatively DTC were found in the liver of 14 of 54 patients (26%). At follow-up only 10 of 40 patients (25%) with DTC-free liver had died of their disease but 9 of the 14 patients with hepatic DTC. Among the 14 patients with hepatic DTC 10 (71%) had developed new liver metastasis, compared to 12 of 40 (30%) in those without hepatic DTC.

CONCLUSION

Hepatic DTC in colorectal cancer patients is associated with reduced overall survival and increased risk of hepatic metastasis development. Further studies are necessary to corroborate our results since the number of patients studied is still limited.