Most important, benign tumors are rarely a threat to life. Malignant tumors are cancer. Cells in malignant tumors are abnormal and divide without control or order. These cancer cells can invade and destroy the tissue around them. The process by which cancer spreads from the original tumor to form new tumors in other parts of the body is called metastasis.
Cancer can cause a variety of symptoms.
When these or other symptoms occur, they are NOT always caused by cancer. They may also be caused by infections, benign tumors, or other problems. It is important to see the doctor about any of these symptoms or about other physical changes. Only a doctor can make a diagnosis. A biopsy is the most reliable way to know whether a medical problem is cancer.