Long-term clinical outcome of phase IIb clinical trial of percutaneous injection with holmium-166/chitosan complex (milican) for the treatment of small hepatocellular carcinoma

Purpose: The purpose of this study was to evaluate the long-term tumor response after phase IIb clinical study and the safety of percutaneous holmium-166 (¹⁶⁶Ho)/chitosan complex injection (PHI) therapy for small hepatocellular carcinoma as a local ablative treatment. ¹⁶⁶Ho is a radioactive isotope derived from natural hotmium-165. We developed a ¹⁶⁶Ho/chitosan complex (Milican, Dong Wha Pharmaceutical Co., Seoul, Korea) using chitosan as a vehicle to retain the radioactive material within the tumor. Experimental Design: Forty patients with single hepatocellular carcinoma <3 cm in maximal diameter were enrolled in this study. The patients either had refused surgery or were poor surgical candidates and were treated with only single session of PHI. Results: Two months after PHI, complete tumor necrosis was achieved in 31 of 40 patients (77.5%) with hepatocellular carcinoma lesions <3 cm and in 11 of 12 patients (91.7%) with hepatocellular carcinoma <2 cm. Tumors recurred in 28 patients during the long-term follow-up period, of which 24 recurred at another intrahepatic site. The 1 -year and 2-year cumulative local recurrence rates were 18.5% and 34.9%, respectively. The survival rates at 1, 2, and 3 years were 87.2%, 71.8%, and 65.3%, respectively. Transient bone marrow depression was serious adverse event requiring hospitalization in two patients. Conclusions: PHI was found to be a safe and novel local ablative procedure for the treatment of small hepatocellular carcinoma and could be used as a bridge to transplantation. A phase III randomized active control trial is clearly warranted among a larger study population.