What is ovarian cancer?
The ovaries are two small glands that form part of the female reproductive system, which is also made up of the vagina, cervix, uterus (womb) and Fallopian tubes. Ovaries have two main functions:
- Produce, store, and release eggs for reproduction
- Produce the female sex hormones oestrogen and progesterone
Ovarian cancer occurs when there are abnormal cells in the ovary which multiply, creating a tumour. Tumours will either be benign or malignant. Benign tumours are non-cancerous and do not usually spread to other parts of the body. They may require some treatment but are rarely life threatening. If the tumour is malignant it is cancerous and when left untreated may spread to other parts of the body.
Your treatment will depend on the type, stage and grade of ovarian cancer you’re diagnosed with. Visit our Ovarian cancer treatment section to read about how the type and stage affect the treatment you receive.
Types of ovarian cancer
When a woman is diagnosed with ovarian cancer she will have one of three types: epithelial, germ cell and sex-cord stromal. Each of these have a number of subtypes. Some types are more common than others and affect women at different ages..
- Epithelial ovarian cancer
Epithelial ovarian cancer is the most common type of ovarian cancer, accounting for around 90% of all cases. Not all epithelial tumours will be malignant (cancerous), some will be benign (non-cancerous).
Here are the subtypes of epithelial ovarian cancer:
High grade serous ovarian cancer is the most common type of epithelial ovarian cancer, accounting for more than half the cases of this type. The majority of these tumours are thought to originate in the Fallopian tube. They occur most often in women between the ages of 40 and 60 and they are commonly treated with a combination of surgery and chemotherapy.
Low-grade serous ovarian cancer is a rare, slow-growing type of epithelial cancer that usually affects younger women (aged between 45 and 55 years). Low-grade serous ovarian cancer is treated with surgery and chemotherapy. Some patients may benefit from hormonal therapy following chemotherapy.
Endometrioid ovarian cancer accounts for around 20% of epithelial ovarian cancer cases. This type affects women of all ages, and it is linked to endometriosis. It’s commonly treated with a combination of surgery and chemotherapy.
Clear cell ovarian cancer is a less common type of ovarian cancer, only accounting for around 6% of epithelial tumours. It mainly affects women over the age of 50 and, like endometrioid ovarian cancer, has a strong association with endometriosis. This type is commonly treated with standard surgery and chemotherapy.
Mucinous ovarian cancer tumours are not common and are generally found in women over the age of 50. They are usually non-cancerous and can be removed by surgery, with or without chemotherapy.
Undifferentiated tumours are the types of ovarian cancer that do not fit neatly into any category. They account for about 15% of epithelial tumours.
Brenner tumours are rare and only account for around 2% of epithelial ovarian cancers. They will generally be benign and are usually treated by removal during surgery.
Ovarian carcinosarcoma is another type of ovarian cancer. These tumours display a mix of epithelial (carcinoma) and stromal (sarcoma) characteristics. Usually presenting in the uterus, it is very rare to find one on the ovary but it can sometimes occur here.
- Germ cell ovarian cancer
Germ cell tumours are rare and account for around 5% of ovarian cancer cases. Starting in germ cells, the cells that go on to develop into eggs, they mainly affect younger women. Most germ cell tumours are benign.
Mature teratomas are a common type of benign germ cell tumours which can be removed through surgery. These types of tumours commonly affect women in their fertile years and could present anytime between teens and forties.
Immature teratomas are malignant and commonly occur at a much younger age. Teenage girls and women in their early 20s are most at risk of this kind of germ call ovarian cancer. They are called immature because the cancer cells are at a very early stage of development. These types of tumours are commonly treated with surgery and chemotherapy, and outcomes are usually very good.
Other types of malignant germ cell cancers include: yolk sac tumours, mixed germ cell tumours and dysgerminomas. These may require surgery, removal of the affected ovary and chemotherapy.
- Sex-cord stromal ovarian cancer
Sex-cord stromal tumours are rare, usually begin, and found in the connective tissue of the ovary. The most common type of tumours are called granulosa cell tumours, of which there are two kinds – adult and juvenile.
Adult granulosa cell tumours usually occur early in the menopause and are slow growing. They can be treated by surgery alone to remove all the tumour with no need for chemotherapy.
Juvenile granulosa cell tumours are usually seen in children and younger women and will be treated by surgery followed by a course of chemotherapy.
Sertoli-Leydig tumours (sometimes called androblastomas) are another type of sex-cord stromal tumour. This type of cancer is most common in women in their 20s and 30s and often associated with symptoms such as voice deepening and excessive hair growth on the face, chest and limbs. These tumours aren’t usually malignant and can be successfully removed by surgery, with no need for any further treatment.
Primary peritoneal and Fallopian tube cancers are also closely related to ovarian cancer.
- Primary peritoneal cancer
Primary peritoneal cancer is very similar to epithelial ovarian cancer both in the way it presents and is diagnosed. It is a rare cancer of the peritoneum, a supportive and protective layer of thin tissue that lines the inside of the abdomen, and it will often be treated with surgery and chemotherapy.
- Fallopian tube cancer
The Fallopian tubes are two long tubes which carry the egg from the ovaries to the womb. Fallopian tube cancer has very similar symptoms to ovarian cancer and can be treated in the same way.
What are the stages of ovarian cancer?
Ovarian cancer is diagnosed at one of four stages. The stage describes how far the cancer has spread inside the body – the higher the stage the further the cancer has progressed.
Stage 1 ovarian cancer: The cancer is contained within one, or both of the ovaries. At this early stage, the cancer will not yet have started to spread.
Stage 2 ovarian cancer: The cancer will have started to spread from the ovaries to other parts of the pelvic region such as the womb, bladder and bowel.
Stage 3 ovarian cancer: By this stage, the cancer will have spread beyond the pelvic area into the abdominal cavity (a large space in your abdomen containing organs that include the liver, pancreas and kidneys) and lymph nodes.
Stage 4 ovarian cancer: The cancer has travelled some distance from the ovaries and into other parts of the body beyond the pelvic region. Organs such as the liver, lungs and brain may be affected.
The earlier the cancer is diagnosed the easier it is to treat.
What are the grades of ovarian cancer?
Different types of tumours grow at different rates, and grading is the method used to predict how quickly a tumour is expected to develop. Like stages, ovarian cancer falls into one of four grades.
Grade 0 ovarian cancer: Also known as borderline tumours as they are the least likely to be cancerous, Grade 0 ovarian cancer tumours are less aggressive, unlikely to spread, and are easier to cure.
Grade 1 ovarian cancer: Grade 1 ovarian cancer tumours are low grade tumours that look very similar to normal tissue and grow very slowly.
Grade 2 ovarian cancer: Grade 2 ovarian cancer tumours grow moderately quickly and are sometimes referred to as intermediate grade tumours.
Grade 3 ovarian cancer: Grade 3 ovarian cancer tumours grow quickly and in a disorganised way. They are the most aggressive type of cancer.