Types of ovarian cancer
This page tells you about the different types of ovarian cancer. There is information about
Types of ovarian cancer
This information is about epithelial cancer of the ovary. Almost 9 out of 10 tumours of the ovary (90%) diagnosed are this type. Other types of ovarian cancer include germ cell tumours (cancer of the egg making cells of the ovary) and sarcomas.
Epithelial ovarian cancer starts in the surface layer covering the ovary. There are various subtypes of epithelial ovarian cancer. Serous epithelial ovarian cancer is the most common type. Other types are mucinous, endometrioid, clear cell, undifferentiated or unclassifiable ovarian cancer. At the moment they are generally treated in the same way. But doctors and researchers are investigating whether the less common subtypes need to be treated in a different way to serous epithelial ovarian cancer.
The different types of epithelial ovarian cancer can also be grouped together according to their behaviour. The behaviour of cancers means how quickly or slowly they grow. Doctors usually call this the grade of the cancer. They group the cancers together as borderline, grade 1 (well differentiated), grade 2 (moderately differentiated) and grade 3 (poorly or undifferentiated).
Cancer cells that look very like normal cells are described as well differentiated. They tend to grow and spread more slowly than cancer with undifferentiated cells. The treatment of borderline ovarian tumours can be different to other types of ovarian cancer because they are unlikely to spread.
You can view and print the quick guides for all the pages in the about ovarian cancer section.
Almost 9 out of 10 tumours of the ovary diagnosed (90%) are this type. So this section discusses treatment for epithelial ovarian cancer.
Epithelial ovarian cancer means the cancer started in the surface layer covering the ovary. There are various types of epithelial cancers of the ovary. Serous epithelial ovarian cancer is the most common type. Researchers are investigating in clinical trials whether the rarer types need to be treated any differently. But at the moment, they are generally treated in a similar way to serous epithelial ovarian cancer. The particular subtype won't make much difference to how the disease behaves or the treatment you will have.
The different types of epithelial ovarian cancer include
- Serous - makes up more than half the diagnosed cases of epithelial ovarian cancer
- Clear cell
- Undifferentiated or unclassifiable
A small number of ovarian cancers are a type called primary peritoneal carcinoma. The cancer develops from the cells that form the membrane around abdominal organs. We have information about primary peritoneal cancer in the question and answer section.
About 1 in 10 epithelial ovarian cancers (10%) are undifferentiated or unclassifiable. These tumours have cells that are so very undeveloped that it is not possible to tell which type of cell the cancer started from.
Around 1 or 2 out of 100 ovarian cancers (1 to 2%) are germ cell cancers. They start from the egg making cells of the ovary. As well as these, there are also non cancerous (benign) forms of germ cell tumour, which doctors sometimes call dermoid cysts. We have information about both these types of ovarian teratoma (a type of germ cell tumour) in the question and answer section.
Other, even rarer, types of cancer can affect the ovary, for example, sarcomas. This section does not cover these rarer types of ovarian cancer. Look in help and support for organisations that produce cancer information. They will be able to give you the information you need about your type of cancer.
The grading of cancers means how the cells look under the microscope. This affects how quickly or slowly they are likely to grow. Doctors group ovarian cancers together as
- Well differentiated (grade 1)
- Moderately differentiated (grade 2)
- Poorly or undifferentiated (grade 3)
About 15 out of 100 epithelial ovarian tumours (15%) are borderline ovarian tumours. They are also called tumours of low malignant potential. This means they are very unlikely to spread. And so are usually easier to cure. The treatment of borderline ovarian tumours can be different to the treatment of other types of ovarian cancer.
As a normal cell grows and matures, it becomes specialised for its role and place in the body. This is called differentiation. Cancer cells can look very like normal cells and are described as well differentiated or low grade. These cancers tend to grow and spread very slowly.
Or the cells can look very primitive and underdeveloped and are known as undifferentiated or high grade cancer. These cancers tend to grow and spread more quickly than low grade ovarian cancers.
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