Old versus New – Tumor Ablation versus Tumor Nanoablation with Particular Emphasis on Liver Tumors

Loco-regional treatments play a key role in the management of hepatocellular carcino‐ ma (HCC). Image-guided tumor ablation is recommended in patients with early-stage HCC when surgical options are precluded. Radiofrequency ablation is currently es‐ tablished as the standard method for local tumor treatment. Despite major advances in tumor ablation techniques the disease recurs in a high proportion of cases. A major limitation in its overall effectiveness is due to the difficulties of heating large tumors. Small regions of viable tumor may still remain even after apparently good tumor ablation by perfusion-mediated tissue cooling, preventing the whole tumor reaching a sufficient temperature for coagulation and necrosis. Moreover simple heating techni‐ ques have trouble discriminating between tumors and surrounding healthy tissues leading to many side effects. In order to overcome these major limitations numerous groups are investigating the use of energy-absorbing agents localized within tumor tissues to facilitate localized heating. A personal answer based on the review of the literature will be offered to the following questions: NIR photothermal therapy, RFA with nanoparticles, or magnetic fluid hyperthermia for the long term management of HCC? How should we deliver nanoparticles: systemically or directly intratumoral? Ablation versus mild hyperthermia: Pros and Cons in the majority of cases, hyper‐ thermia is applied in one of two ways: a) high temperature for short time periods commonly referred to as ablation, or b) lower temperatures for long time periods, of‐ ten called mild hyperthermia. The former is used to kill cells directly with heat and consequently can be used to thermally ablate tumor. The second method is just above physiological temperature, and these temperatures are more often used to trigger re‐ lease from thermosensitive drug carriers. Both approaches can be combined with heat-sensitive drug targeting. There are many ways to induce nanoparticle mediated thermal therapy in solid tumors including absorption of infrared light, radiofrequency ablation and magnetically induced heating. These approaches have demonstrated high efficacy in preclinical models of HCC and are already tested in human clinical trials.