Update on treatment of liver metastases: focus on ablation therapies

Hydrothermal Duodenal Mucosal Resurfacing: Role in the Treatment of Metabolic Disease

The duodenum has become recognized as a metabolic signaling center that is involved in regulating insulin action and, therefore, insulin resistance states such as type 2 diabetes. Bariatric surgery and other manipulations of the upper intestine, in particular the duodenum, have shown that limiting nutrient exposure or contact in this key region exerts powerful metabolic effects. Early human clinical trial data suggest that endoscopic hydrothermal duodenal mucosal resurfacing is well tolerated in human subjects and has an acceptable safety profile. This article describes the rationale for this endoscopic approach and its early human use, including safety, tolerability, and early efficacy.

Laser ablation of liver tumors: An ancillary technique, or an alternative to radiofrequency and microwave?

Radiofrequency ablation (RFA) is currently the most popular and used ablation modality for the treatment of non surgical patients with primary and secondary liver tumors, but in the last years microwave ablation (MWA) is being technically improved and widely rediscovered for clinical use. Laser thermal ablation (LTA) is by far less investigated and used than RFA and MWA, but the available data on its effectiveness and safety are quite good and comparable to those of RFA and MWA. All the three hyperthermia-based ablative techniques, when performed by skilled operators, can successfully treat all liver tumors eligible for thermal ablation, and to date in most centers of interventional oncology or interventional radiology the choice of the technique usually depends on the physician’s preference and experience, or technical availability. However, RFA, MWA, and LTA have peculiar advantages and limitations that can make each of them more suitable than the other ones to treat patients and tumors with different characteristics. When all the three thermal ablation techniques are available, the choice among RFA, MWA, and LTA should be guided by their advantages and disadvantages, number, size, and location of the liver nodules, and cost-saving considerations, in order to give patients the best treatment option.

Characterization of Pancreatic Cancer Cell Thermal Response to Heat Ablation or Cryoablation

One of the most lethal carcinomas is pancreatic cancer. As standard treatment using chemotherapy and radiation has shown limited success, thermal regimens (cryotherapy or heat ablation) are emerging as viable alternatives. Although promising, our understanding of pancreatic cancer response to thermal ablation remains limited. In this study, we investigated the thermal responses of 2 pancreatic cancer cell lines in an effort to identify the minimum lethal temperature needed for complete cell death to provide guidance for in vivo applications. PANC-1 and BxPC-3 were frozen (-10°C to -25°C) or heated (45°C-50°C) in single and repeated exposure regimes. Posttreatment survival and recovery were analyzed using alamarBlue assay over a 7-day interval. Modes of cell death were assessed using fluorescence microscopy (calcein acetoxymethyl ester/propidium iodide) and flow cytometry (YO-PRO-1/propidium iodide). Freezing to -10°C resulted in minimal cell death. Exposure to -15°C had a mild impact on PANC-1 survival (93%), whereas BxPC-3 was more severely damaged (33%). Exposure to -20°C caused a significant reduction in viability (PANC-1 = 23%; BxPC-3 = 2%) whereas -25°C yielded complete death. Double freezing exposure was more effective than single exposure. Repeat exposure to -15°C resulted in complete death of BxPC-3, whereas -20°C severely impacted PANC-1 (7%). Heating to 45°C resulted in minimum cell death. Exposure to 48°C yielded a slight increase in cell loss (PANC-1 = 85%; BxPC-3 = 98%). Exposure to 50°C caused a significant decline (PANC-1 = 70%; BxPC-3 = 9%) with continued deterioration to 0%. Double heating to 45°C resulted in similar effects observed in single exposures, whereas repeated 48°C resulted in significant increases in cell death (PANC-1 = 68%; BxPC-3 = 29%). In conclusion, we observed that pancreatic cancer cells were completely destroyed at temperatures <-25°C or >50°C using single thermal exposures. Repeated exposures resulted in increased cell death at less extreme temperatures. Our data suggest that thermal ablation strategies (heat or cryoablation) may represent a viable technique for the treatment of pancreatic cancer.

Visible to near-infrared refractive properties of freshly-excised human-liver tissues: marking hepatic malignancies

The refractive index is an optical constant that plays a significant role in the description of light-matter interactions. When it comes to biological media, refraction is understudied despite recent advances in the field of bio-optics. In the present article, we report on the measurement of the refractive properties of freshly excised healthy and cancerous human liver samples, by use of a prism-coupling technique covering the visible and near-infrared spectral range. Novel data on the wavelength-dependent complex refractive index of human liver tissues are presented. The magnitude of the real and imaginary part of the refractive index is correlated with hepatic pathology. Notably, the real index contrast is pointed out as a marker of discrimination between normal liver tissue and hepatic metastases. In view of the current progress in optical biosensor technologies, our findings may be exploited for the development of novel surgical and endoscopic tools.