My friend suffers from leukemia she's 19 years old . she s ill since 2018 but now she stopped the traitement . how long she will live ?

With out knowing which type of leukemia she has it is not possible to make a prediction. For some acute leukemia’s I would recommend she not start any long books. For others she will have a normal life span. But even with knowing more details I always quote Yogi Berra: “It is difficult to make predictions. Especially about the future.”

It all depends on the circumstances that treatment has been stopped, was she getting too sick, complications, no more treatments available? Regardless, her oncologist remains the best resource for a specific prognosis.