Ovarian cancer is a cancer that begins in an ovary. It results in abnormal cells that have the ability to invade or spread to other parts of the body. When this process begins, symptoms may be vague or not apparent, but they become more noticeable as the cancer progresses. These symptoms may include bloating, pelvic pain, and abdominal swelling, among others. Common areas to which the cancer may spread include the lining of the abdomen, lining of the bowel and bladder, lymph nodes, lungs, and liver.