Thermoablation of colorectal liver metastases promotes proliferation of residual intrahepatic neoplastic cells.

BACKGROUND

Resection of liver neoplasms is believed to promote growth of residual intrahepatic neoplastic cells. As the effects of radiofrequency thermoablation (RFA) are still unknown, we aimed to compare the influence of RFA versus liver resection on residual intrahepatic neoplastic cells.

METHODS

A primary metastasis was established by injection of syngenic CT-26 coloncarcinoma cells into the right liver lobe of Balb/C mice. Five days later, 3 x 10(5) GFP-transfected CT-26 tumor cells were injected intraportally, and the primary metastasis was treated by resection (group I, n = 7) or RFA (group II, n = 7). The effect of resection/RFA on the growth of single intrahepatic GFP neoplastic cells was evaluated by intravital microscopy 7 days later.

RESULTS

Resection of a primary metastasis enhanced the proliferation of residual intrahepatic neoplastic cells, compared with the control group. RFA led to an increased survival of residual neoplastic cells (5% +/- 2% vs 1% +/- 1% single cells) and significantly promoted the proliferation of neoplastic cells, compared with resection (13% +/- 4% vs 2% +/- 2% micrometastases).

CONCLUSIONS

RFA strongly promotes intrahepatic growth of residual neoplastic cells. On the basis of our findings, RFA should not be recommended as an alternative curative treatment to resection. Furthermore, if RFA is performed as palliative therapy, postinterventional chemotherapy may be advisable to overcome the stimulation of residual neoplastic cells by RFA.