Thermal ablation therapies in patients with breast cancer liver metastases: a review

BACKGROUND

The liver is involved in about half of patients with metastatic breast cancer. Unfortunately systemic chemotherapy as the treatment of choice is limited. Due to multifocality and/or insufficient remnant liver volume, the majority of liver metastases are also unresectable. Currently, thermal ablations are used in these patients with acceptable impact.

METHODS

We reviewed studies on radiofrequency ablation (RFA), laser-induced thermotherapy (LITT) and microwave ablation (MWA) regarding local tumour response, progression and survival indexes in patients with breast cancer liver metastases (BCLM).

RESULTS

The reviewed literature showed positive response rates of 63 % to 97 % in RF-ablated lesions, 98.2 % in LITT-treated lesions and 34.5-62.5 % in MW-ablated lesions. Median survival was 10.9-60 months using RFA, 51-54 months after LITT and 41.8 months using MWA. Five-year survival rates were 27-30 %, 35 % and 29 %, respectively. Local tumour progression ranged from 13.5 % to 58 % using RFA, 2.9 % with LITT and 9.6 % with MWA.

CONCLUSION

The reviewed literature demonstrated that ablation therapies either as single therapy or combined with other locoregional therapies are a good alternative as an adjunction to resection in patients with resectable lesions or with positive response using chemotherapy. However, multicentre randomised studies should be conducted to obtain further evidence of the benefits of these treatments in patients with BCLM.

Use of gold nanoshells to constrain and enhance laser thermal therapy of metastatic liver tumours

PURPOSE

To investigate the impact of intravenously injected gold nanoparticles on interstitially delivered laser induced thermal therapy (LITT) in the liver.

METHODS

3D finite element modelling, ex vivo canine liver tissue containing gold nanoparticles absorbing at 800 nm, and agar gel phantoms were used to simulate the presence of nanoparticles in the liver during LITT. Real-time magnetic resonance temperature imaging (MRTI) based on the temperature sensitivity of the proton resonance frequency shift (PRFS) was used to map the spatiotemporal distribution of heating in the experiments and validate the predictions of 3D finite element simulations of heating.

RESULTS

Experimental results show good agreement with both the simulation and the ex vivo experiments. Average discrepancy between simulation and experiment was shown to be 1.6 degrees C or less with the maximum difference being 3.8 degrees C due to a small offset in laser positioning.

CONCLUSION

A high nanoshell concentration in the surrounding liver parenchyma, such as that which would be expected from an intravenous injection of gold nanoshells ( approximately 120 nm) acts as both a beam stop for the laser and secondary heat source for the treatment, helping to better heat the lesions and confine the treatment to the lesion. This indicates a potential to use nanoparticles to enhance both the safety and efficacy of LITT procedures in the liver.