Only a doctor can diagnose cancer. But in many cases, people consult a doctor only after the disease is far advanced. A person should therefore be alert to any physical change that may be a symptom of cancer. Detecting cancer while a tumor is small and confined to one location greatly increases the chances of a cure.
Cancer checkups. Many cancers cause no symptoms in their early stages. To detect early cancers, the American Cancer Society recommends that people aged 20 to 40 have a cancer-related checkup by a physician every 3 years. People aged 40 or older should have a checkup every year. A cancer-related checkup usually includes a physical examination. Physicians watch carefully for any visible signs of cancer when they perform physical examinations. Depending on the patient, screening tests for specific types of cancer may also be performed. Screening tests may include a breast X ray called a mammogram to detect breast cancer in women. A mammogram can detect some breast cancers before any lumps can be felt.
Physicians recommend that beginning at age 50, patients have routine tests for colon cancer. In one such test, called a fecal occult blood test (FOBT), the patient uses special kit to collect tiny samples of stool (solid body wastes). Laboratories test the samples for microscopic amounts of blood, which may indicate cancer. The Pap test, another recommended yearly test for women, has greatly reduced the death rate from cancer of the uterus. In the Pap test, experts examine cells scraped from the cervix under a microscope. Microscopic signs of cancer can be seen 5 to 10 years before symptoms appear.
A blood test for a protein called prostate-specific antigen (PSA) may detect early prostate cancer. PSA is made only in the prostate gland. Elevated levels of the protein may mean that the gland has become cancerous.