As the American Cancer Society explains, symptoms of cancer generally include fatigue that does not improve with rest, localized pain in one area of the body that does not respond to medications, changes in the color and texture of skin and unexplained weight loss. Several symptoms are unique to specific types of cancer, such as finding blood in the urine or coughing up blood from the lungs.
According to the American Cancer Society, many forms of cancer progress slowly and remain undetected in the body until they begin to manifest obvious signs and symptoms in their advanced stages. For example, pain related to cancer often occurs as a result of excessive tumor growth that causes the affected organ to bulge and press on neighboring nerves or organs. People with brain tumors often experience chronic headaches and changes to their vision. Cancer commonly causes fevers as it begins to compromise a person's immune system. People who are affected with breast cancer often find a lump growing in one or both breasts or experience bloody discharge from the nipples.
The American Cancer Society urges patients with unexplained symptoms to speak with a doctor and to try to determine the source of the complaint. Many people ignore the signs and assume their health issues are nothing serious. This can give cancer unnecessary time to develop untreated.