The risk of regression after refractive surgery is similar between epilasik / Lasik, and is predominantly determined by the residual corneal thickness, how high the original myopia was, and other systemic collagen disorders that the patient may have.
These risks can may be reduced for high-risk patients by the concomitant performance of an adjunctive collagen cross-linking procedure (commonly referred to as Lasik-extra, or epilasik-extra). Discuss your risks with your attending ophthalmologist who may be in the best position to advise you further!