Introduction: Most literatures researched radiofrequency ablation (RFA) for early hepatocellular carcinoma (HCC) defined the early tumor size as 3cm or less. However, detection rate of HCC smaller than 2 cm became increasing since high risk patients had received regular screening and the imaging techniques has been much improved. Whether RFA or percutaneous ethanol injection (PEI) is better for a patient with such a small HCC is still controversial. Methods: We retrospectively obtained patients with single HCC 2 cm in diameter or smaller from the computerized medical records database in a local teaching hospital located at southern Taiwan, diagnosed during January 1, 2002 to April 30, 2008. Those patients received RFA (RFA group) or PEI (PEI group) as the first-line nonsurgical treatments were enrolled for further analysis. We compared baseline characteristics of RFA and PEI groups, including gender, age, possible risk factors of recurrence, and prognostic factors. Then, we analyzed recurrent rate, time to recurrence, survival rate, complication rate, mean cost of each treatment, and hospital stay of RFA and PEI groups. Results: There were 32 patients qualified for the study design, including 22 in PEI group¡G13 males and 9 females with mean age was 63.73 years; and 10 in RFA group¡G7 males and 3 females with mea age was 58.30 years¡CNo statistically significant differences between RFA and PEI groups were observed with respect to baseline characteristics. Nevertheless, there was significant difference between these two groups with respect to mean hospital stay (p=0.007) and mean cost (p¡Õ0.001): mean cost of PEI was NTD $16934.7; mean cost of RFA was NTD $51677.6, the difference was NTD $34732.9. There was no difference respect to complication rate, recurrent rate, time to recurrence and overall survival rate between RFA and PEI groups. Conclusion: For patients with single HCC 2 cm in diameter or smaller (i.e. very early HCC), we concluded that: if under similar basic background, the cost of RFA was much higher than that of PEI, but no difference in the complication rate, recurrent rate, time to recurrence and overall survival rate between these two treatment.

HIFU is the upcoming technology for noninvasive or minimally invasive tumor ablation via the localized acoustic energy deposition at the focal region within the tumor target. The presence of cavitation bubbles had been shown to improve the therapeutic effect of HIFU. In this study, we have investigated the effect of HIFU on temperature rise and cavitation bubble activity in ethanol-treated porcine liver and kidney tissues. We have also explored changes in the viability and proliferation rate of HepG2, SW1376, and FB1 cancer cells with their exposure to ethanol and HIFU. Tissues were submerged in 95% ethanol for five hours and then exposed to HIFU generated by a 1.1 MHz transducer or injected into focal spot before HIFU exposure. Cavitation events were measured by a passive cavitation detection technique for a range of acoustic power from 1.17 W to 20.52 W. The temperature around the focal zone was measured by type K or type E thermocouples embedded in the samples. In experiments with cancer cells, 2.7 millions cells were treated with concentration of ethanol at concentration 2%, 4%, 10%, 25%, and 50% and the cell were exposed to HIFU with power of 2.73 W, 8.72 W, and 12.0 W for 30 seconds. Our data show that the treatment of tissues with ethanol reduces the threshold power for inertial cavitation and increases the temperature rise. The exposure of cancer cells to various HIFU power only showed a higher number of viable cells 24 to 72 hours after HIFU exposure. On the other hand, both the viability and proliferation rate were significantly decreased in cells treated with ethanol and then HIFU at 8.7 W and 12.0 W even at ethanol concentration of 2 and 4 percent. In conclusion, the results of our study indicate that percutaneous ethanol injection (PEI) and HIFU have a synergistic effect on cancer cells ablation. / acase@tulane.edu