Radar and Chris, I have arthritis in my left knee cap and very bad in my right foot.
I also have degenerative changes in the spine which refers down to my legs. I was convinced I would need a knew hip the pain was so bad but I don't, the pain was caused by the back.
My left knee pain has been eased by an X ray guided injection into the right foot. Walking awkwardly because of the painful foot was obviously adding to the knee pain.
It is easy to assume that any new aches and pains are due to your cancer but it may well be related joint pain from muscle spasms from either the back or the hips (or like in my case the knees and foot)