The limited efficacy of current approaches to the treatment of patients with hepatic cancer, including external beam radiation therapy and cytotoxic chemotherapy, has reawakened interest in the use of internal radiation therapy.
METHODS.
The authors reveiwed series of patients with liver metastases or hepatocellular carcinoma (HCC) treated with 1) interstitial irradiation and direct intratumoral injection of 90 Y microspheres, 2) intraarterial infusion of 131 I-Lipiodol, 3) intraarterial infusion of 90 Y microspheres, or 4) parenteral administration of radiolabeled monoclonal antibodies.
RESULTS.
High dose rate interstitial irradiation with afterloading of 192 Ir resulted in local control of hepatic metastases for a median of 8 months and complete tumor eradication in 2 patients. Direct intratumoral injection of 90 Y microspheres reduced the size of 90.6% of tumors and completely destroyed them in 8 patients.
Treatment with arterial 131 I-Lipiodol resulted in a 17-92% response rate as well as a case of complete remission of unresectable HCC. It was found to be most effective against small tumors. No response was observed with liver metastases from colorectal carcinoma. Partial response was commonly achieved when patients with unresectable liver metastases or HCC were treated with intraarterial 90 Y microspheres. Among four patients whose HCC became resectable following treatment with 90 Y microspheres, two cases of complete remission were documented.
In a prospective randomized trial, 131 I-antiferritin combined with chemotherapy was no more effective than chemotherapy alone.
CONCLUSIONS.
The different approaches to internal radiation therapy that are reviewed in this article represent several ways in which radiation can be selectively targeted to hepatic tumors without undue radiation to the nontumorous liver.
However, the efficacy of each of these therapies still needs to be evaluated in randomized controlled trials.