Ovarian cancer is a type of carcinoma that causes one or more tumours to develop in the ovaries. The ovaries are a pair of small, walnut shaped organs that are responsible for the release of eggs (ovum) during the female reproductive cycle.
Epithelial ovarian cancer is the most common subtype of this disease. It develops from epithelial cells (or epithelium) that form the outer layer of the ovary. Many epithelial ovarian cancers may originate in the fallopian tubes, which connect the ovary to the uterus.
Ovarian cancers are generally diagnosed in women over 50, however, it can affect almost anyone with ovaries – including women, teenagers, transgender men, non-binary individuals, and intersex people - at any age.
Types of Epithelial Ovarian Cancer
Epithelial ovarian cancers can be divided into the following categories based on which type of the epithelium is affected.
Serous Carcinomas
Serous carcinomas are the most common subtype of epithelial ovarian cancers. These cancers develop from the serous membrane of the ovary, which is a thin membrane that lines internal organs. There are two types of serous carcinomas, which are distinguished by tumour grade.
High-grade serous carcinomas
High-grade serous carcinomas are the most common subtype of this disease. When these tumours are analysed under the microscope, cancer cells appear highly abnormal and with no real structure or pattern. This indicates a high-grade tumour, which is cancer that develops quickly and aggressively. High-grade serous carcinomas are rarely caught early, have high recurrence rates, and may have a poorer prognosis.
Low-grade serous carcinomas
Low-grade serous carcinomas are rare, with tumour cells appearing slightly or moderately abnormal. This indicates a low-grade tumour, which are cancers that are slow-growing, and generally less aggressive. Low-grade serous carcinomas are generally found in younger patients, and are less sensitive to chemotherapy. These tumours are usually less aggressive and may have a better prognosis.
Endometrioid Carcinomas
Endometrioid carcinomas are a rare subtype of epithelial ovarian cancers that are often associated with the condition endometriosis. They often develop with an endometrioma (or chocolate cyst), which develop on the ovary from endometrial tissue. Endometrioid carcinomas can be slow-growing, and often have a better prognosis than other epithelial ovarian cancers.
Mucinous Carcinomas
Mucinous Carcinomas are rare subtypes of epithelial ovarian cancers that is often detected early. Mucinous cancer cells secrete a thick, protective mucus, which are generally not found in the ovaries. In some cases, this may suggest that this is a secondary cancer (cancer that has metastasised from another part of the body). When caught early, mucinous carcinomas generally have a good prognosis.
Clear Cell Carcinomas
Clear cell carcinoma is a rare subtype of epithelial ovarian cancer that is often detected early. It may be linked to the condition endometriosis, but this is not always the case. Clear cell carcinomas are often resistant to chemotherapy. While this type of tumour is aggressive, they may have a good prognosis.
Borderline Ovarian Tumours
Borderline ovarian tumours, or ovarian low malignant potential tumours, are a less common subtype of epithelial ovarian tumours that are not classified as a cancer. They develop in the epithelium of the ovary and often grow slower than other forms of ovarian cancer. These types of tumours are often diagnosed early, and are generally diagnosed in adults between the ages of 20-40.
Treatment
If an ovarian cancer is detected, it will be staged and graded based on size, metastasis (whether the cancer has spread to other parts of the body) and how the cancer cells look under the microscope. Staging and grading helps your doctors determine the best treatment for you.
Ovarian cancers can be staged using the Federation of Gynecology and Obstetrics (FIGO) system from stage I to IV:
- Stage I: cancer cells are confined to one or both ovaries only. This stage is also known as early-stage cancer.
- Stage II: cancer cells have grown deeper into nearby organs in the pelvis, such as the uterus, fallopian tubes, bladder and/or bowel. This is also known as localised cancer.
- Stage III: the cancer has become larger and has spread beyond the pelvis into the lining of the abdomen (peritoneum). Lymph nodes are also often affected. This is also known as advanced or metastatic cancer.
- Stage IV: the cancer has spread to more distant organs, such as the lungs or the liver. This is also known as advanced or metastatic cancer.
Cancers can also be graded based on the rate of growth and how likely they are to spread:
- Grade I: cancer cells present as slightly abnormal and are usually slow growing. This is also known as a low-grade tumour.
- Grade II: cancer cells present as abnormal and grow faster than grade-I tumours. This is also known as an intermediate-grade tumour.
- Grade III: cancer cells present as very abnormal and grow quickly. This is also known as a high-grade tumour.
Once your tumour has been staged and graded, your doctor may recommend genetic testing, which analyses your tumour DNA and can help determine which treatment has the greatest chance of success. In particular, they may look for mutations in the hereditary breast cancer genes (BRCA1 and BRCA2), which can cause an increased risk in developing ovarian cancer. They will then discuss the most appropriate treatment option for you.
Treatment is dependent on several factors, including fertility, type, stage of disease and overall health.
Treatment options for the epithelial subtype may include:
- Surgery, potentially including:
- Total hysterectomy (removal of the uterus).
- Bilateral salpingo-oophorectomy (removal of both ovaries and fallopian tubes).
- Unilateral salpingo-oophorectomy (removal of one ovary and fallopian tube).
- Lymphadenectomy (removal of affected lymph nodes).
- Removal of other organs (only required in some cases where the cancer has spread beyond the pelvis).
- Chemotherapy.
- Targeted therapy (usually offered in stages II-IV).
- Radiation therapy (rare).
- Clinical trials.
- Palliative care.
In patients who have the borderline ovarian tumour subtype, surgery is usually curative and further treatments are usually not required.
For more information on the treatment options, please refer to the Rare Cancers Australia Treatment Options page.
Ovarian Cancer Treatment and Fertility
Treatment for ovarian cancer may make it difficult to become pregnant. If fertility is important to you, discuss your options with your doctor and a fertility specialist prior to the commencement of treatment.
Risk factors
While the cause of ovarian cancer remains unknown, the following factors may increase your risk of developing the disease:
- Having a family history of ovarian, breast, uterine and/or bowel cancer.
- A mutation in the BRCA 1 and BRCA 2 genes.
- Having Lynch syndrome.
- Having certain medical conditions such as endometriosis.
- Use of hormone replacement therapy (HRT).
- Having a history of tobacco smoking.
- Being obese.
- Reproductive history, including:
- Women who have never had children.
- Women who have had assisted reproduction.
- Women who have had children over the age of 35.
- Having early puberty.
- Having late menopause.
- Having Ashkenazi Jewish ancestry.
Not everyone with these risk factors will develop the disease, and some people who have the disease may have none of these risk factors. See your general practitioner (GP) if you are concerned.
Early symptoms
Early-stage ovarian cancer may be asymptomatic. As the cancer progresses, some of the following symptoms may appear:
- Abdominal bloating/swelling.
- Abdominal/pelvic pain and/or pressure.
- Changes in appetite, such as feeling full quickly or not feeling hungry.
- Urinary changes, such as changes in frequency and urgency.
- Changes in bowel habits, such as constipation and diarrhoea.
- Unexplained weight loss or weight gain.
- Unexplained fatigue.
- Indigestion and/or heartburn.
- Changes in menstrual periods, such as irregular periods, unusual vaginal bleeding, or vaginal bleeding post menopause.
- Pain during sex.
Not everyone with the symptoms above will have cancer, but see your general practitioner (GP) if you are concerned.
Diagnosis/diagnosing
If your doctor suspects you have ovarian cancer, they may order the following tests to confirm the diagnosis and refer you to a specialist for treatment.
Pelvic examination
The doctor will inspect the abdomen for any swelling or masses, followed by your genitalia. The doctor will then insert two fingers into your vagina while simultaneously pressing on your abdomen with their other hand to feel your uterus and ovaries. Following this, the doctor may use a device called a speculum into your vagina, which will separate the vaginal walls and allow viewing of your vaginal canal and cervix for any visible abnormalities. You many request a family member, friend, or nurse to be present during this exam.
Imaging tests
The doctor will take images of your body using magnetic resonance imaging (MRI), a computed tomography scan (CT scan), pelvic ultrasound (including abdominal and trans-vaginal ultrasounds) and/or positron emission tomography (PET scan), depending on where it is suspected the cancer is. The doctor may also look at other parts of the body and looks for signs of metastasis.
Blood tests
A blood test may be taken to assess your overall health and help guide treatment decisions. Additional blood tests may be conducted to check for tumour markers, which are indicative of cancer cells. The most common tumour marker for ovarian cancer is CA125. Levels of CA125 may be higher in cases of ovarian cancer, but are not used as a screening tool as high CA125 levels can be higher for other reasons. Blood tests may also examine your full blood count (FBC) and levels of hormones and chemicals in your blood.
Biopsy
Once the location of the cancer has been identified, the doctor will perform an diagnostic procedure to determine your diagnosis. In many cases, diagnosis is confirmed after surgical removal of the affected ovary. However, if it is suspected the cancer has spread, the doctor will perform a biopsy to remove a section of tissue using a needle. This is often done by a fine needle aspiration (FNA), a core needle biopsy (CNB), or by surgical means (excisional or incisional biopsy). In patients who are suspected to have ovarian cancer, diagnosis can often be confirmed after surgery to remove the ovary These samples will then be analysed for cancer cells.
Prognosis (Certain factors affect the prognosis and treatment options)
While it is not possible to predict the exact course of the disease, your doctor may be able to give you a general idea based on the rate and depth of tumour growth, susceptibility to treatment, age, overall fitness, and medical history. Generally, early-stage ovarian cancers have a better prognosis and survival rates. However, if the cancer is advanced and has spread, the prognosis may not be as good and there may be a higher risk of cancer recurrence. It is very important to discuss your individual circumstances with your doctor to better understand your prognosis.
References
Some references are to overseas websites. There may be references to drugs and clinical trials that are not available here in Australia.