Micrometastatic Colorectal Cancer Lesions in the Liver

Abstract

A surgical resection of metastatic liver lesions from colorectal cancer contributes to an improved prognosis. However, the postoperative recurrence rate remains high, particularly in the residual liver. This is probably the result of the failure to detect small lesions. In the present study, we histologically examined the presence of intrahepatic micrometastases, which are considered to be related to recurrence in the residual liver. Intrahepatic micrometastases were histologically examined in 31 resected specimens of 25 patients undergoing a hepatic resection because of metastasis to the liver from colorectal cancer. Micrometastases were found in 14 of 25 cases (56.0%). They were located in the portal veins, central veins, sinusoid, and bile ducts. The longest distance from the main metastasis was 38.2 (mean 7.5 +/- 8.0) mm. The size of the macrometastases became larger, and the frequency of micrometastases and the distance of micrometastases from macrometastases had a tendency to increase. Continuous invasion of the macrometastases into the micrometastases through the vasculature or bile duct was also observed. These results suggested that some micrometastases observed in the metastatic liver from colorectal cancer were thus seeded from the primary lesions, while other micrometastases originated from the macrometastatic lesions as satellite lesions.

Effects of tirapazamine on experimental colorectal liver metastases after radiofrequency ablation1

“…Local tumour recurrence may be due to incomplete destruction of the tumour lesion or to stimulation of satellite micrometastases. Indeed, examination of resection specimens has shown that more than 50 per cent of colorectal liver metastases are surrounded by microsatellite lesions 27 . Improved imaging and RFA procedures are needed to minimize incomplete destruction of the tumour mass 28 .…”

“…Improved imaging and RFA procedures are needed to minimize incomplete destruction of the tumour mass 28 . However, RFA is unlikely to be effective in eradicating satellite micrometastases, at least in part owing to their invisibility using current imaging modalities 27 . Adjuvant chemotherapy or targeted therapy may therefore have a place in the treatment of patients with colorectal cancer undergoing RFA treatment for colorectal liver metastases.…”