My 70 yr old mom just found out she is anemic could she have cancer?

my mom is 70. she had a colonoscopy last year which was fine. she went to the doc today for a normal check up and her blood work she had a few weeks ago came back she is anemic. the doc wants to test her stools to see if she is ping any blood but she said she hasnt saw anything could she have cancer. i am so scared!!!