Hepatic radioembolization with yttrium-90 containing glass microspheres: preliminary results and clinical follow-up

The treatment of hepatic tumors remains unsatisfactory. These lesions receive most of their blood supply from the hepatic artery, therefore the hepatic artery administration of beta-emitting particulate radiopharmaceuticals is an attractive approach to deliver therapeutic irradiation to the liver and differentially to tumors within the liver.

A Phase I dose escalation study of the hepatic tolerance to radiation delivered by 90Y containing glass microspheres was carried out in 24 patients with hepatic malignancy. Doses of 90Y microspheres to achieve an estimated whole-liver nominal absorbed radiation dose of 5000 cGy (two patients), 7500 cGy (six patients), 10,000 cGy (seven patients), 12,500 cGy (six patients), and 15,000 cGy (three patients) were administered via the hepatic artery. The administered nominal absorbed radiation dose (NARD) was estimated based on liver volume determined from CT scans and the assumption of uniform distribution of microspheres throughout the liver.

No hematologic, hepatic or pulmonary toxicity was encountered in the dose range examined during a mean follow-up period of up to 53 mo. Reversible gastritis or duodenitis was encountered in four patients without imaging or biopsy evidence for extrahepatic deposition of microspheres. Response data, based on CT scans obtained 16 wk after treatment, showed progressive disease in eight patients, stable disease in seven patients, minimal response in four patients and partial response in five patients. Subsequent follow-up revealed three long-term survivors at 204, 216 and 228 wk.

These preliminary data demonstrate that in the examined dose range, radiation may be safely delivered to liver tumors by means of 90Y glass microspheres with encouraging response data.