Introduction
 The ovaries contain primitive cells, which are cells that go on to become eggs, and epithelial cells. Primitive cells that become cancerous are called germ cell or dysgerminoma cancers. These cancers behave like testicular germ cell or seminoma cancers. Epithelial cell cancers of the ovary are more common than germ cell or dysgerminoma cancers. Names of different types of epithelial ovarian cancers include mucinous or serous cystadenocarcinoma, clear cell carcinoma and endometrioid carcinoma of the ovary.
How common is Ovarian Cancer?
Ovarian cancer is the 6th commonest cancer in Singapore. It is the second commonest female genital tract cancer. Ovarian cancer is a disease of older women because its risk increases with the number of ovulations.
Risks and Causes
The risk increases with the number of ovulations. Pregnancy before age 25, early menopause and the use of oral contraceptives that decrease the number of ovulations, all decrease the risk of ovarian cancer. Similarly, women who menopause late and those who have their first pregnancy after 30 are at higher risk.
Ovarian cancer is known to run in families. In women who have a sister or mother with this disease, the risk of developing ovarian cancer is increased twenty-fold. Ovarian cancer also runs in certain families with breast and colon cancers. There is now evidence to suggest that certain genes are involved in causing this disease.
Symptoms
Among female genital tract cancers, epithelial ovarian cancers are difficult to prevent or cure because they rarely have symptoms or signs at the outset. Symptoms develop only when the cancer is advanced. Routine gynaecological examination can detect silent early cancers.
Symptoms suggest advanced disease. These symptoms are tummy discomfort and swelling, bloating or wind, pain, or change in bowel habits.
Diagnosis
Physical examination, including PAP smear, is necessary. A marker in the blood, called CA-125, is raised in about 80% of patients with epithelial ovarian cancers. However, it is also raised in non-cancerous conditions, such as endometriosis. The result must therefore be interpreted in the light of other findings.
Pelvic ultrasound will delineate the size of the cancer and show if other areas of the region are involved. Computerised scans (CT) of the region and chest x-rays are usually scheduled. X-rays of the intestines and kidneys are sometimes required to determine if those organs are also involved by cancer.
Final staging of the cancer is determined at surgery. Any suspicious mass is biopsied. Biopsies of the inner lining of the tummy, called peritoneum, and the fluid within the tummy, are sent for histology, i.e. examination under a microscope. With these, the final stage of the disease is known.
Clinical examinations, x-rays and pathology reports all help the medical team decide what the progress of an individual case of ovarian cancer may be. Then, the appropriate course of treatment will be put into action. The treatment strategy will vary from person to person. With prompt and appropriate treatment, the outlook for a person with ovarian cancer is fair.
Treatment
Epithelial ovarian cancer tends to spread along the outer surfaces of the organs within the tummy.
The aim of surgery is to remove as much of the cancer as possible. Often this includes removing both ovaries, the uterus and its surrounding fat, the fat within the tummy called the omentum, all visible cancer along the surface of the organs in the tummy, and biopsies of the inner lining of the tummy called the peritoneum, even if these are not visibly involved. Fluid within the tummy is also removed and sent for testing.
After surgery, some patients require chemotherapy. Patients with very early stage epithelial ovarian cancer where the entire cancer is removed by surgery require chemotherapy to prevent cancer recurrence. Patients with stage III epithelial ovarian cancer where the cancer involves the lining of the tummy called the peritoneum or the outer surface of organs within the tummy are offered chemotherapy to prolong survival. Chemotherapy involves giving courses of infusions of medicines into hand veins. It is associated with temporary hair loss, nausea and vomiting, loss of appetite and occasional numbness of the fingers or toes.
Occasionally, chemotherapy in injected into the tummy to coat the inner lining of the tummy. This is associated with occasional abdominal discomfort.
Treatment is very individualised.
Frequently Asked Questions
Can I go for screening for ovarian cancer?
Screening for ovarian cancer is difficult. Blood tests are not very specific. Ultrasounds of the pelvis are time-consuming, uncomfortable and may not detect very small cancers. It is better to see your doctor for an annual pelvic examination and PAP smear as these may detect most cancers of the female genital tract.
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