Low grade serous cancer is a type of carcinoma (epithelial cell cancer). It is usually hormone receptor positive (estrogen +/- progesterone). Epithelial ovarian cancer is the most common type of ovarian cancer. Approximately 10% of epithelial serous ovarian cancers are low-grade.

The ovaries are a pair of female reproductive organs located on either side of the uterus (womb). Epithelial cells line the surface of the ovary. Each ovary is about the size and shape of an almond. They connect to the uterus via a long thin tube called the Fallopian tube. The ovary produces eggs which travel through the Fallopian tube to the uterus. They also produce oestrogen and progesterone hormones.

Low-grade serous peritoneal cancer is considered a variant of low-grade serous ovarian cancer. The peritoneum is the internal layer of the abdomen. In some women low-grade serous cancer starts in the peritoneum instead of the ovary. The medical treatment for both conditions is the same.