I'm confidently stating that there was never any information released about the queen having multiple myeloma, because there never ever was any such information released from any official source. Google it, and you'll see that's the case.
The only claims that she "may" have had this were in books written by Gyles Brandreth and Boris Johnson, neither of whom are official mouthpieces for palace information. Those books are the only sources of this hypothesis.
I don't know what you think you saw on the news but it was not an official statement, it was probably a discussion about the claims in these books, none of which have been confirmed or denied by the palace, so may or may not be true.
You shouldn't go round asserting that the queen definitely had a particular cancer when all you know is that it was claimed in a book that she "might" have had it. Basically you have no idea whether she did so you shouldn't state it as fact.
In fact as a "healthcare provider" you should know better than to assert that speculation is the truth.