No they can’t. There is no 100% cure for any type of cancer. Some treatment of cancers have better success rates than others but none are 100% successful. Also doctors talk about being in remission as opposed to cured.
They can be cured. Just because there is no current known cure for every cancer from the big pharmacies doesn't mean they can't be cured. I'm sure @GeordieGeezer will be aware of holistic cures as well