Types of ovarian cancer

Most ovarian cancers start in the cells that cover the surface of the ovary (the epithelium) and are called epithelial ovarian cancers.

There are several types of epithelial ovarian cancer. They include:

  • serous – the most common type
  • mucinous
  • endometrioid
  • clear cell
  • undifferentiated or unclassifiable.

It’s now thought that high-grade serous ovarian cancer may start in the fallopian tube and then spread to the ovary. But all epithelial ovarian cancers and cancers of the fallopian tube are treated in a similar way.

We have more information about fallopian tube cancer.

Borderline tumours

Borderline tumours are made up of abnormal epithelial cells, but they aren’t true cancers. They can sometimes turn into cancer, but most don’t.

Borderline tumours usually grow slowly and are unlikely to spread. They are staged in the same way as ovarian cancers and are always stage 1.

Non-epithelial ovarian cancers

There are non-epithelial cancers that can affect the ovaries, but this information is only about epithelial ovarian cancer.

We have more information about germ cell ovarian tumours of the ovary. These non-epithelial tumours start in the ovarian cells that produce eggs. They usually affect young women.

Back to Understanding ovarian cancer

What is cancer?

Cancer is a disease of our cells. Sometimes cells go wrong and become abnormal. They keep dividing to make more abnormal cells which form a lump or tumour.

The ovaries

The ovaries are two small organs in a woman’s pelvis. They are part of the reproductive system and also create hormones.

Why do cancers come back?

Sometimes, tiny cancer cells are left behind after cancer treatment. These can divide to form a new tumour.