Brachytherapy in the treatment of solitary colorectal metastases to the liver.

It is well-established that 30-40% of patients with solitary liver metastases from primary colorectal tumors can be cured by resection. Conventional radiation therapy has had only a palliative role in treating liver metastases because the dose that the liver will tolerate is far below a tumoricidal dose. In contrast, brachytherapy allows one to deliver a tumoricidal dose to the tumor while limiting the dose to surrounding normal tissue to the tolerance dose. As a pilot study, 125I seeds were implanted into unresectable hepatic metastases, or positive margins of resection, at the time of surgery. This report concerns six patients whose liver lesions were the only known site of disease and in whom precipitous drops in carcinembryonic antigen (CEA) levels followed the implants. Recurrence was observed in only one of the 11 implanted site, with a median follow-up of 12 months.