A NEW, EFFECTIVE, AND SAFE THERAPEUTIC OPTION USING PROTON IRRADIATION FOR HEPATOCELLULAR-CARCINOMA

Background/Aims: Conventional radiation is almost useless for hepatoce llular carcinoma (HCC) because of the severe adverse effects of the ir radiation to the accompanying liver cirrhosis. In contrast, the proton beam has Bragg peak, which limits distribution of the beam. The aim o f this study was to prove the usefulness of proton irradiation for HCC . Methods: The proton irradiation was performed in 32 nodular lesions in 24 patients with HCC who had unresectable tumors or serious complic ations; the proton irradiation was performed either as monotherapy (15 lesions) or as combination therapy to insufficient Lipiodol-targeted chemotherapy (Kodama Co. Ltd., Tokyo, Japan) (17 lesions). The energy was 250 MeV, and 50-87 Gy (76.5 +/- 9.5, mean +/- SD) in total was irr adiated for a time period of 17-69 days. Results: After 1 year, size r eduction was seen in 12 out of 13 lesions (92%) in the monotherapy gro up and 9 out of 9 lesions (100%) in the combination therapy group; aft er 2 years, size reduction was seen 4 out of 5 lesions (80%) in the mo notherapy group and 5 out of 5 lesions (100%) in the combination thera py group. Local tumor control has being assured for 2 years of the obs ervation, which is continuing for another 2 years. None of the patient s have experienced any serious adverse effects. Conclusions: These res ults show that proton irradiation is a new, safe, and effective therap eutic option in cases of HCC, even in patients with unresectable tumor s or those with serious complications.