Ovarian Cancer
Research over the last decade has transformed our understanding of the biology of ovarian cancer. We now understand that ovarian cancer is a general term for a series of distinct cancer types, with different cellular origins, that share an anatomical location but are molecularly unrelated. Epithelial ovarian cancer is associated with over 90% of the serious forms of the disease, with Germ Cell and Stromal tumours being much more uncommon. Among the epithelial ovarian cancers are high-grade serous, the most common histotype, followed by clear cell, low- grade serous, and mucinous ovarian cancers. Each of these has a different clinical behaviour in response to chemotherapy, association with inherited genetic mutations, and survival.
Genetic risk
Mutations in the genes BRCA1 or BRCA2 increases the risk of developing ovarian, breast and certain other cancer. Genetic risk is particularly associated with high-grade serous ovarian cancer, where ~17% of women with this type carry either a BRCA1 or BRCA2 germline mutation. Our work, and that of other researchers, has shown that only just over half of women with these mutations have a strong family history of ovarian or breast cancer, and therefore guidelines now recommend all women with high-grade serous ovarian cancer are offered genetic testing irrespective of family history. Knowledge of the presence of such mutations can be important for preventing cancer in other family members, such as daughters or sisters.
Advice about genetic testing can be obtained at Familial Cancer Centres located in major cities and some large regional towns.
BRCA1 and BRCA2 are part of a tiny machine that repairs DNA in the cell. These genes perform particularly important tasks and hence their mutation substantially increases the risk of developing cancer. In recent years other genes participating in DNA repair and processes that control cell growth have been identified that can also contribute to the development of cancer when damaged. Therefore some genetic testing clinics are now testing for these new genes in addition to BRCA1 and BRCA2, including offering re-testing of women in whom a mutation wasn't found with the earlier more limited tests available.
How common is ovarian cancer?
In 2017, it is estimated that 1,580 new cases of ovarian cancer will be diagnosed in Australia. Ovarian cancer is estimated to be the eighth most commonly diagnosed cancer in women in Australia. 1
The risk of a woman being diagnosed with ovarian cancer before the age of 80 is about 1 in 80. 2
Of the ~1500 women diagnosed with ovarian cancer each year, some 75% will be diagnosed with advanced disease (stage III or IV)1. As there is no screening test for ovarian cancer, knowing your body and being aware of symptoms is essential.
In 2014, there were 974 deaths caused by ovarian cancer in Australia.2 The overall five-year survival rate for women diagnosed with ovarian cancer is approximately 44%.1
1. Australian Institute of Health and Welfare 2017. Cancer in Australia 2017. Cancer series no.100. Cat. no. CAN 100. Canberra: AIHW
2. Australian Institute of Health and Welfare 2017. Australian Cancer Incidence and Mortality (ACIM) books: Ovarian Cancer. www.aihw.gov.au/acim-books