
Well, that's the promise anyway.
It's called focal cryoablation, which allows doctors to freeze cancer cells at negative 40 degrees, using 3D biopsies to target the treatment directly to the tumor. Sounds like a targeted cold therapy to me -- not unlike the targeted radiation of IGRT compared to the old shotgun approach with external beam.
In conventional crytotherapy, the treatment would freeze the prostate in order to kill off clusters of cancer cells. Side effects are considered rather mild, although the big risk is the impairment of sexual function, so I suppose it depends on your definition of “mild.” The freezing of the prostate may destroy the nerve bundles responsible for erections.