Surgery for colon cancer can cause erectile dysfunction (ED). The surgery can affect a man's ability to get an erection in two ways. First, the surgery can damage nerves that send signals to the body resulting in an erection. This problem has become less common as surgeons have developed more precise techniques that allow them to avoid the nerves. Second, the surgery can cause a man to become less interested in sex because of discomfort or concerns about sensitive areas near his penis.
Talk to your doctor about treatments and drugs that may help restore your ability to get an erection.