Hi and welcome to HCm. Cancer is the last you should think of. This looks like blood clot, and causes of abnormal bleeding in women are various. Most of them arent serious. She should do hormone blood levels and pelvic ultrasounds to rule out ovary disorder such as cysts or endometriosis. You didnt mention her age. Different causes are common in different age groups. In peri and postmenopause uterus cancer is more common and bleedings are usually irregular. In middle aged woman pregnancy should always be excluded. The last possibility is pelvic infection which can cause bleeding, disharge and ain in lower abdomen. I suggest to do tests i ve mentioned and then plan further treatment. Wish you good health and good luck Sir.