Sorry about the news of your niece.

If you go to the info pages for various different cancers on this website I think most give survival rates.

But please tread lightly for a number of reasons.  One good reason is that you may not truly want the answer, never mind that you may end up with information that your niece doesn't want to know and accidentally treat her differently because of it.  But the best reason to tread lightly is that survival stats are out of date literally the minute they are published.  During the 5-10 years that they are following up on previous patients the newer patients can be receiving even better treatment.  Treatment is coming on leaps and bounds for many cancers if, sadly, not all.

I haven't looked up the stats myself and posted them here in case anyone who doesn't want to know accidentally comes across them, but they are available if you go to the page for the relevant cancer.

Best wishes to your family dealing with all this, it must be horrific.

LJx