Electromagnetic thermotherapy using fine needles for hepatoma treatment

Hepatocellular carcinoma can be treated with heat-based therapies, especially radiofrequency ablation (RFA). However, RFA has limited efficacy and is quite expensive. We designed a new system using fine needles combined with an alternating magnetic field to generate hyperthermia for the treatment of hepatocellular carcinoma in a rat hepatoma model. Our aims are to assess the efficacy of our method and determine survival up to 30 days.

An N1-S1 cell line was inoculated into the livers of Sprague-Dawley rats, generating tumors after 14 days. The animals were randomized into 5 groups and treated after laparotomy either with normal saline (group I), iron oxide nanoparticles (group II), fine needles (group III), fine needles and iron oxide nanoparticles combined (group IV) or self-designed two-part needles placed under ultrasonographic guidance percutaneously (group V). Every rat was placed in an alternating magnetic field. The temperature in the treatment area was maintained between 55 and 60 °C. At day 30 after treatment, tumor volumes and mortality were assessed and histology samples were studied.

Tumor volumes were significantly reduced and survival rate was prolonged in groups III, IV and V versus groups I and II (P < 0.05). On pathological examination, groups III, IV and V presented obvious necrosis, apoptosis, calcifications and inflammatory changes in the treatment area.

Our study demonstrates that hyperthermia generated by fine stainless-steel needles combined with an alternating magnetic field effectively inhibits hepatoma growth in rats and prolongs their survival. Further, this method can be applied percutaneously under ultrasonographic guidance.