Ovarian cancer is the ninth most common cancer in Australian women and the sixth most common cause of cancer death. Every year, 1200 Australian women are diagnosed and 800 women die from this disease. Due to lack of adequate screening techniques and non-specific symptoms, most women are diagnosed in the advanced stages of the cancer, meaning that the survival rates of ovarian cancer are low in comparison to other cancers. Sadly, the five-year survival rate for women diagnosed with advanced stage ovarian cancer is 20%, compared with a five-year survival rate of 78% for women diagnosed at an early stage.
What is ovarian cancer?
Ovarian cancer occurs when the normal division and growth of ovarian or Fallopian tube cells is disrupted, leading to uncontrolled cell growth. These abnormal cells usually also spread to tissues or organs throughout the peritoneal cavity.
There are four main types of ovarian cancer, classified by the type of ovarian cells affected:
- Epithelial ovarian cancers comprise 90% of ovarian cancers. Unfortunately, they also tend to be the most aggressive.
- Borderline cancers are a less aggressive and less common type of epithelial ovarian cancer.
- Germ cell ovarian cancers arise from the eggs within the ovary. This type of cancer is uncommon, and tends to occur in women under 30 years of age. It generally responds well to treatment, and young women may still be able to have children afterwards if only one ovary is affected.
- Sex-cord stromal ovarian cancers originate from the tissue that releases female hormones. These are uncommon and can occur at any age.
How is ovarian cancer diagnosed?
There is no tool currently available for early detection of ovarian cancer; thus ovarian cancer is often detected late, after the tumour has spread through the peritoneal cavity and complete surgical removal is quite difficult. If ovarian cancer is suspected, a transvaginal ultrasound can be used to help detect ovarian cancer. In this test, the ultrasound probe is inserted into the vagina to provide a clear view of the ovaries. If the ultrasound shows an abnormality, the doctor may then do a CA-125 test to further investigate the possibility of ovarian cancer. A diagnosis of ovarian cancer can only be definitively made following surgery and examination of a biopsy by a pathologist.
The symptoms of ovarian cancer can be vague and can be similar to the symptoms of several other conditions that can be a part of everyday life. Symptoms can include swelling and pain in the abdomen; changes in usual menstrual pattern or postmenopausal bleeding; gastrointestinal symptoms such as heartburn, nausea and bloating; changes in bowel habits, such as constipation and diarrhoea; tiredness and appetite loss; and unexplained weight loss or weight gain. If you experience these symptoms for more than three to four weeks, see your doctor.
Unlike the Pap smear test, which tests for cervical cancer before symptoms appear, there is no screening test for ovarian cancer. The Pap smear test does not detect ovarian cancer.
What are the risk factors of ovarian cancer?
- Age - most women are over age 55 when diagnosed with ovarian cancer
- Family history - around 10% of ovarian cancers are caused by inheriting a damaged gene. Most hereditary ovarian cancers are associated with the BRCA1 or BRCA2 genes, also associated with familial breast cancers. A small number of hereditary ovarian cancers are associated with a particular type of familial colorectal (bowel) cancer
Women who ovulate less appear to be somewhat protected. Therefore, risk factors include:
- Having few or no children
- Early commencement of menstruation or late menopause
- Having a first child after the age of 30
The long-term use of a combined oral contraceptive pill and breastfeeding lowers the risk of
developing ovarian cancer.
Options for ovarian cancer treatment
The type of treatment depends on the age of the woman, the type of ovarian cancer, and its stage of progress. The most common treatment method is an individualised combination of surgery and chemotherapy. During surgery, either a portion or the entire ovary may be removed. If the cancer has spread to surrounding areas, these affected organs may also have to be removed. After surgery, chemotherapy is used to kill any remaining cancer cells. Unfortunately, up to 30% of ovarian cancer patients do not respond to chemotherapy, and another 40% can develop resistance to the chemotherapy during treatment.
Garvan's research into ovarian cancer
The Garvan Institute is home to one of the largest cancer research programs in Australia with a focus on hormone-based cancers. The Ovarian Cancer Research Group works very closely with ovarian cancer specialists at the Gynaecological Cancer Centre at the Royal Hospital for Women, Randwick, and together, have established a large tissue bio-bank. Our Group is investigating blood-based DNA biomarkers that may indicate the presence of ovarian cancer.
This test is aimed at detecting early-stage ovarian cancers. Our research team is also investigating the mechanisms to resistance to chemotherapy, with the aim of offering better treatments to patients with late-stage ovarian cancer. Ultimately, the results of our research will be used to develop early diagnostic tests, individualised treatments, and a better prognosis for ovarian cancer sufferers.
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