The ovaries are part of the female reproductive system and are located on either side of the uterus, or womb. They are almond shaped and approximately two to four centimetres in diameter. The role of the ovaries is to produce ova/eggs, as well as hormones that are involved in the menstrual cycle and fertility.

While cells in our body usually grow in a controlled and organised fashion, when they grow abnormally, they form a growth or a tumour, which can be benign or malignant. Benign tumours are not cancerous and do not spread, but a malignant tumour, also known as a cancer or carcinoma, will continue to spread in an uncontrolled fashion through the body unless it is treated. Ovarian cancer is a malignant tumour of the ovary.

Types of Ovarian Cancer

Although they all affect the ovaries, there are different types of ovarian cancer. When a diagnosis is made, the type of cancer is identified. The types are:

  • Epithelial: epithelial ovarian cancers are derived from cells covering the surface of the ovary and comprise over 90% of ovarian cancers. Epithelial ovarian cancer is further divided into subtypes being serous, mucinous, endometrioid, clear cell and undifferentiated. Epithelial ovarian cancer can also be divided into grades depending on how abnormal the cancer looks under the microscope.
  • Germ cell: germ cell ovarian cancers arise from the eggs within the ovary and can also be classified into several subtypes. Germ cell cancers are uncommon, and tend to occur in women less than 30 years of age. Generally this type responds well to treatment, and young women may still have children afterwards if only one ovary is affected.
  • Sex-cord stromal: Sex-cord stromal ovarian cancers originate from the tissue that releases female hormones. These are uncommon and can occur at any age. They respond well to treatment and young women may still have children if only one ovary is affected.
  • Borderline: Borderline ovarian cancers are a group of epithelial tumours that are not as aggressive or malignant as the epithelial cancers. They generally have a better outcome, whether diagnosed early or late.

The treatment and likely outcome for a particular type of ovarian cancer will vary with each individual case and needs to be discussed with a gynaecological oncologist.

How does ovarian cancer spread?

Ovarian cancer spreads to the other parts of the body by shedding cancerous cells into the abdominal cavity which then attach to the abdominal lining and continue to grow. Cancerous (malignant) cells can also implant on:

  • Bowel
  • Bladder
  • Liver
  • Omentum (the curtain of fatty tissue that hangs from the stomach and intestines)
  • Diaphragm (situated under the lungs)

Ovarian cancer may also spread via the lymph glands which are part of the immune system and often swell when our bodies are fighting an infection. These glands are all over the body, but it is those in the pelvis, around the aorta and in the groin and neck that are usually affected by ovarian cancer.

Another way of spreading is via the bloodstream or through the diaphragm, affecting the lungs and causing fluid to collect.