How effective is laser treatment for removing melasma?

I am worried that as I get older, it seems inevitable that my melasma will increase, even with proper care. I try to block it with sunscreen when the sun is strong, but with the UV rays being so intense these days, it doesn't seem to be working. How long do the effects of melasma removal treatments at a dermatology clinic usually last? I am curious because some people say it works, while others say it actually got worse.