Cancer that begins in the ovaries. Ovarian cancer is the sixth most com¬ mon cancer in women. Because it is difficult to detect at an early stage, ovarian cancer is more likely to spread from the ovary and be fatal than is cancer of the cervix or endometrium (the lining of the uterus). Early stages of ovarian cancer usually have no symptoms. A tumor may first be detected when a doctor feels an enlarged ovary as part of a routine pelvic examination. At later stages, a woman may have vague intestinal problems, a feeling of fullness in her abdomen, or abdominal or pelvic pain or discomfort.