Ovarian cancer is an uncommon cancer with 1500 Australian women diagnosed with this disease each year. This means a 1% lifetime risk for Australian women and makes it about ten times less common than breast cancer. Unfortunately, there is no effective screening available for ovarian cancer and it is most commonly diagnosed late. Consequently, the chances of dying from this disease are higher than for any other women-specific cancer. Women should be aware of the most frequently reported symptoms in order to seek medical advice and advice as to any specific intervention that may be needed.
At only 2-4 cm in size, these small organs have multiple functions. The ovaries need to house all the eggs (oocytes) that are released each cycle with ovulation. The fluid filled sacs (called follicles) in which the eggs are housed produce hormones that ensure the environment in the womb is ideal for the implanting of an embryo. The ovaries provide women with the signals and the hormones to develop from girls to women physically and give women protection against bone loss and heart disease. For these multiple functions, the ovary is made up of many different cell types any of which have the potential to develop cancer.
There are three main types of ovarian cancer:
- Epithelial cancers: Epithelial cells form the outer layer of the ovary and cancer in these cells are the most common type of ovarian cancer – accounting for about 90% of all cases.
- Germ cell Cancers: This type of cancer originates from the cells that would otherwise make the eggs and account for 5% of ovarian tumours mostly diagnosed in women <30years of age.
- Sex-cord stromal cell ovarian cancer: These tumours originate from the cells that produce hormones and account for the remaining 5% of ovarian cancers affecting women of any age.
- Borderline tumours: 15% of all ovarian tumours are classified as “borderline” type with features that are between a benign (non cancerous) and malignant (cancerous) ovarian tumour. These require follow up but are not as aggressive as other ovarian tumours and are not given the same designation as other ovarian cancers.
Symptoms are frequently vague and non-specific and may be indicators for many other benign medical conditions. Commonly, symptoms shared by most women with ovarian cancer include:
- Feeling bloated or distended;
- Urinary urgency;
- Abdominal or pelvic pain;
- Feeling full after a meal.
Other presentations include irregular bleeding between periods, pain with intercourse, unexplained changes in weight, indigestion, change in bowel habits, fatigue and back pain.
Ovarian Cancer Australia has produced a “Symptom Diary” to help women track their symptoms every day over a 4-week period. It focuses on the symptoms that are most frequently reported by women who are diagnosed with ovarian cancer and enables women to better record and communicate the symptoms they are experiencing with their doctor.
Most ovarian cancers occur sporadically – that is they do not have a genetic component and occur at random. There are however some risk factors that may be associated with ovarian cancer.
Family history and Genetics Faulty genes that have been inherited from either parent are an important risk factor for the development of ovarian cancer, accounting for up to 15% of diagnosed cancers. Most hereditary ovarian cancer involves mutations in the BRCA 1 or BRCA 2 genes or associated with the most common type of genetic bowel cancer called Lynch syndrome or HNPCC.
Women who inherit a faulty BRCA1 gene have approximately a 40% lifetime risk of developing ovarian cancer, while women who inherit a faulty BRCA2 gene have approximately a 10-15% risk of developing ovarian cancer. These two gene abnormalities are also associated with breast cancer.
Women with HNPCC have about a 12% lifetime risk of developing ovarian cancer and there is also a risk of colon, renal tract, gastrointestinal and endometrial cancer with this genetic syndrome.
Endometriosis on the ovary is associated with specific forms of ovarian cancer. This risk is relatively low and it is not recommended that women with endometriosis have their ovaries out because of this risk.
Lifestyle factors such as smoking, high fat diets and obesity increase the risk of ovarian cancer.
Hormonal history Women who started menstruating early (before the age of 12years) or had late menopause (>50years) are at increased risk.
Childbearing Women who have never had children are at increased risk of developing ovarian cancer. Importantly, women who have been on the oral contraceptive pill are at lower risk of developing ovarian cancer, with 10 years of usage of the pill reducing the risk of ovarian cancer by about 50%. When combining the above two risk factors –the more cycles that women have with a rise and fall in hormones and a greater number of ovulations – the greater the risk – this is the reason that the pill and having more children is protective against this type of cancer.
Tests for diagnosis
Unfortunately there are no tests that can diagnose ovarian cancer. Your GP generally starts some preliminary investigations that include:
- Transvaginal Ultrasound An ultrasound performed with a vaginal probe allows the most detailed view of the ovaries above all other imaging. There are certain features within the ovary that may make your doctor suspicious of cancer and may then refer you to a gynaecologist.
- Blood tests – Tumour markers Some tumour markers or proteins may be elevated with ovarian cancer. These markers do not only rise with ovarian cancer and mean that they are poor indicators of ovarian cancer, since they may be elevated in other conditions such as endometriosis, infection or inflammation and benign ovarian cysts. The tumour markers CA125, CA 199 and CEA are the most frequently ordered and will vary according to the ovarian cancer. It is important to know that elevations in these markers is not diagnostic of an ovarian cancer.
- Other imaging CT scans, MRI and X-Rays are also ordered on occasion to rule out other medical conditions.
The management of women with ovarian cancer will be overseen by a multidisciplinary team that includes a gynaecological oncologist. This is a gynaecologist with specialist training and skill in treating cancers of the female reproductive tract. Other specialists may include a medical oncologist and radiation oncologist if chemotherapy or radiotherapy is needed. Most ovarian cancer is treated surgically and this allows for ‘staging’. Staging is where the spread of ovarian cancer is determined and which organs are affected. The staging process is important in the planning of additional treatment and affects the prognosis of the disease.
Surgery for ovarian cancer is still mostly done by laparotomy (an incision made through the middle of the abdomen) since access to all areas of the abdomen is needed, although laparoscopy may be used in certain situations. At surgery it is important to “debulk” the ovarian cancer and reduce tumour deposits to less than 10mm. Removal of the uterus and cervix, tubes and ovaries is standard, with additional removal of organs or parts of organs (such as the bowel) based upon the spread of the cancer.
Monitoring of the cancer will continue intensely for the first five years spreading out over the following five. Surveillance is essential and physical examinations, blood tests (monitoring with tumour markers) and ultrasound scans and CTs may be used for progress monitoring.
Prognosis and survival rates will depend on the tumour type, the staging at surgery, age at diagnosis and response to treatment. 5-year survival rates vary between 10-75%.