Ovarian cancer is most effectively treated when detected early, but because of its lack of symptoms at that time, it is usually not found until later stages when it has spread to other organs and tissues. Later signs of ovarian cancer may include unexpected weight loss, urinary frequency, abdominal bloating and pelvic discomfort. Sometimes, changes in bowel habits are noticed as well. Ovarian cancer occurs in one of three forms: epithelial tumors, stromal tumors and germ cell tumors. Most are epithelial tumors. While no one knows what causes ovarian cancer, women with an inherited mutation of the breast cancer gene BRCA1 or BRCA2 are at greater risk for developing it. Other risk factors include being over the age of 50, having estrogen replacement therapy, having never given birth, smoking, undergoing fertility treatment, using an intrauterine device and being diagnosed with polycystic ovary syndrome. Most patients diagnosed with ovarian cancer are treated with surgery to remove the ovaries, proximal lymph nodes, uterus, fallopian tubes and some abdominal tissue, as well as with chemotherapy.