Is there a connection between metastatic colon cancer and difficulty walking?

Can be serious. Metastatic colon cancer often involves the bones, including the vertebrae that protect the spinal cord and provide support to your body. If you are having difficulty walking, the worst case scenario is having a metastatic lesion involve a vertebral body, and possibly causing nerve damage by compressing the spinal cord. As this can be very serious, you should consult your oncologist immediately.
Perhaps. Metastatic colon cancer can go to the brain or spine and thus cause difficulty walking, but it, or the treatment for it, can also cause electrolyte disturbances that can affect your brain, balance as well. So if it is happening to you or yours, call your doctor please.