Ovarian cancer is any cancerous growth that may occur in different parts of the ovary. The majority of ovarian cancers arise from the epithelium (outer lining) of the ovary. According to the American Cancer Society it is the 8th most common cancer among women in the USA (excluding non-melanoma skin cancers). In the UK ovarian cancer is the fifth most common cancer among females, after breast cancer, bowel cancer, lung cancer and uterine cancer (cancer of the uterus).