Crow underwent minor surgery on Wednesday (22FEB06) and will now have precautionary radiation therapy.
Doctors insist they have caught the disease early and the outlook is good. Seven times Tour de France winner Armstrong - who is a testicular cancer survivor - has already been in touch with the singer, and is sure she will recover.
He says "Once again I'm reminded of just how pervasive this illness is, as it has now touched someone I love deeply.
"Based on my contact in recent days with Sheryl, her doctor and her family, I am confident that she will have a full and complete recovery and the world will be a better place for it."