Clinical Trials of High-Intensity Focused Ultrasound for Cancer: Concerns Arising from Low Post-Hoc Power.

ABSTRACT

Prospective controlled trials of high-intensity focused ultrasound for cancers were evaluated. Post-hoc power was <0.80 in 30/47 trials and in 22/39 trials with positive results, indicating low quality in most trials. Unscientific endpoints, small sample sizes, and high dropout rates led to low post-hoc power that caused inter-trial heterogeneity and overestimated the therapeutic effect. The objective response rate was not a substitute for survival time for estimating the sample size and assessing the efficacy. The present data can interpret a paradox HIFU is considered to have slighter cytotoxicity to non-cancer tissues and no radiation but is frequently combined with chemotherapy and/or radiotherapy in practice.