CHICAGO — Radiation segmentectomy offers an alternative treatment for unresectable liver carcinoma that avoids the complications of traditional external beam therapy, according to a study presented at the annual meeting of the Radiological Society of North America.
Radiation segmentectomy involves infusing an internal point source of radiation—in this case, yttrium-90 glass microspheres (MDS Nordion's TheraSpheres)—to the tumor site, said Robert J. Lewandowski, M.D., of William Beaumont Hospital, Royal Oak, Mich.
With radiation segmentectomy, “tumoricidal radiation doses approaching 5,000 Gy can be achieved in portions of the liver—i.e., in the tumor—with virtually no adverse clinical events,” he said.
In contrast, tumoricidal radiation doses delivered by traditional external beam therapy—via a collimated beam of radiation from an external source—typically range between 100 and 120 Gy. Radiation doses greater than 35 Gy given to normal parenchyma increase the risk of radiation hepatitis, which is characterized by alkaline phosphatase elevation, hepatomegaly, jaundice, and ascites. Patients typically require complex pretreatment planning.
In this study, 18 patients underwent Y90 microsphere treatment for unresectable hepatoma (12 patients) or metastatic liver disease (6 patients). The microspheres were infused via the hepatic artery to the right lobe in 13 patients, the left lobe in 4 patients, and both lobes in 1 patient. All patients had good performance status and normal liver function at baseline. All patients received treatment on an outpatient basis.
The median absorbed tumor dose was 926 Gy, and the median dose to normal parenchyma was 14 Gy. Results from liver function tests remained within normal limits for all patients for a median follow-up of 60 days. No patient showed signs of radiation hepatitis during the follow-up period.
The success rate for the procedure is greater than 30%, principal investigator Riad Salem, M.D., told this newspaper. The procedure can also be repeated if necessary. Dr. Salem is the director of radiation oncology at Northwestern Memorial Hospital, Chicago. He is also a consultant for MDS Nordion.