The Collaborative International Dictionary
Untreatable
Untreatable \Un*treat"a*ble\, a.
Incapable of being treated; not practicable. [R.]
--Dr. H.
More.
Douglas Harper's Etymology Dictionary
Wiktionary
untreatable
a. Not treatable; impossible to treat.
Usage examples of "untreatable".
An untreatable fungal disease called anthracnose is wiping out the lovely dogwoods not just here but everywhere in America.
Warren Zevon died in West Hollywood of mesothelioma, a rare form of untreatable lung cancer usually associated with asbestos, on September 7th, aged 56.
The alternative is to accept that Jeremy died because Of a cosnuc crapshoot, that he was unlucky, that he just happened to get a type of rare, untreatable cancer.