We here report the long-term (4years) effects of proton irradiation for HCC,in comparison with that of Lipiodol-targeted chemotherapy (1-TAI), in order to clarify the role of this new therapy for the treatment of HCC.[Materials and Methods] Informed consent was obtained from 48 HCC patients. 75 HCC lesions in the 48 patients which were treated with either proton irradiation alone (Mono : 46 lesions) or with Lipiodol-targeted chemotherapy (1-TAI) plus proton irradiation (Combi : 29 lesions) were included in the analysis. Proton beam was provided by the cynclotoron of the National Laboratory for High Energy Physics (KEK). Total amount of 75 Gy (mean) of the proton beam was targeted to HCC,which ranged from 1 to 12cm in size. The results from these patients were compared with those from 42 patients (65 HCC lesions) treated with 1-TAI alone (1-TAI group), whose background did not differ from the proton groups. All tumor was followed up by CAT scan and ultrasonography. [Results] 1) : After
1 yr, the reduction of tumor size was observed in 40 out of 46 lesions (87%) in Mono, 21 out of 29 lesions (72%) in Combi, compared with 30 of 65 lesions (46%) in 1-TAI group. After 2 yrs, size reduction was seen in 11 of 12 (92%) in Mono, 10 of 10 (100%) in Combi and 10 of 16 (63%) in 1-TAI group. After 4 yrs, size reduction was seen in 1 of 1 (100%) in Mono, 3 of 3 (100%) in Combi and 2 of 3 (67%) in 1-TAI group. 2) : Local tumor control rate (no local recurrence) was significantly higher in the proton groups (Mono and Combi) than in the 1-TAI group. By Kaplan and Meier's methods, cumulative local tumor control rates, at the end of 1st yr : 97% for both Mono and Combi, 70% for 1-TAI group, at the end of 4th yr : 60% for Mono, 90% for Combi, 30% for 1-TAI.3) : Survival rate was also significantly higher in the proton groups than in the 1-TAI group during follow-up period. Cumulative survival rates at the end of 2nd and 4th yrs, were 87%, 74% for the proton groups, and 74%, 45% for the 1-TAI group, respectively. 4) : Excellent QOL was maintained in all cases treated with proton therapy during observation period. [Conclusion] HCC patients treated with proton irradiation showed more excellent local tumor control as well as better survival and QOL,in comparison with 1-TAI,which lasted for at least 4 yrs. This therapy is safe and has a special merit of excellent QOL during the treatment without any complaints. Advantages of this methods are the availability for deep-seated tumor, patient with serious complications.