Cancer detection: Methods used to find cancer in persons who may or may not have symptoms. Symptoms of cancer are abnormal sensations or conditions that persons can notice that are a result of the cancer. It is important to your doctor for regular checkups and not wait for problems to occur. But you should also know that the following symptoms may be associated with cancer: changes in bowel or bladder habits, a sore that does not heal, unusual bleeding or discharge, thickening or lump in the breast or any other part of the body, indigestion or difficulty swallowing, obvious change in a wart or mole, or nagging cough or hoarseness. These symptoms are not always a sign of cancer. They can also be caused by less serious conditions. Only a doctor can make a diagnosis. It is important to see a doctor if you have any of these symptoms. Don't wait to feel pain. Early cancer often does not cause pain.