Evolving Approaches for Controlling Liver Metastases in CRC - Episode 7
Distinct selection criteria exist for determining which patients with liver metastases from colorectal cancer should undergo ablation therapy, including patients who are ineligible for curative surgical resection, have recurrent disease, those with less than 3 lesions, and patients with lesions of less than 4 centimeters, states David Liu, MD.
In the CLOCC clinical trial, patients with liver-only disease (no extrahepatic disease) and no more than 9 hepatic metastases received standard of care chemotherapy with or without radiofrequency ablation, describes Marwan Fakih, MD. There was no difference in overall survival (OS) when the CLOCC data was first published, and the study was regarded as a negative trial, says Fakih. However, at a median follow-up of 9.7 years, after the data were allowed to mature there was an improvement in OS with radiofrequency ablation.
In this long-term follow-up, patients treated with radiofrequency ablation plus chemotherapy experienced a 42% reduction in the risk of death. The median OS in the ablation arm was 45.6 months compared with 40.5 months with chemotherapy alone (HR, 0.58; P = .01). If hepatic metastases cannot be resected, radiofrequency ablation should be used, Fakih says. The data show that it is important to aggressively treat patients with liver-only disease and to aim for whole cytoreduction when possible. If the disease in the liver cannot be controlled, then OS will likely be impacted, adds Fakih.
One of the more recently developed ablative procedures is stereotactic beam radiotherapy (SBRT). This technique uses external beam radiation to target the tumor, explains Liu. This approach can be useful in patients with clearly visible lesions that can be targeted, which differs fundamentally from those who are eligible for Yttrium-90-resin microsphere therapy, which targets the tumor vasculature. Patients undergoing SBRT require fiducial placements, which are gold radiologic markers inserted percutaneously into the tumor.
SBRT has been associated with a high rate of control of liver metastases, comments Fakih, but it is not considered a definitively curative technique and does not replace surgery. The only technique that is considered curative at this time is surgical resection.