Lost.....

on dec 20th she went in for surgery on her knee after tearing a tendon in it. they found a growth on her and we had it removed.. we found out yesterday that it is cancerous... we don't know what is going to happen now and are all very very sad... except her, cause she's always happy.
why does this have to happen to the good dogs in this world... why does it have to happen to anyone, dog or person.