Ovarian cancer forms in tissues of the ovary. Most ovarian cancers are either ovarian epithelial carcinomas (cancer that begins in the cells on the surface of the ovary) or malignant germ cell tumours (cancer that begins in egg cells).
Symptoms of ovarian cancer
During the early stages of ovarian cancer, symptoms are often vague and ill-defined. Symptoms may include pelvic or abdominal discomfort, bloating, difficulty eating or feeling full, increased abdominal size, or urinary symptoms (urgency and frequency).
In some women, ovarian cancer is initially suspected when a mass or lump is felt during a routine pelvic examination. However, a mass is not always detectable in the early stages of ovarian cancer. Even when a mass is detected, it does not necessarily mean that the woman has ovarian cancer. A number of other non-cancerous conditions can cause masses.
Because the initial symptoms are vague and nonspecific, the majority of women have advanced stage disease by the time the diagnosis is made. At this point, the woman may have more prominent symptoms such as abdominal distention (swelling), nausea, or a significant loss of appetite.
Treatment of ovarian cancer
The most important first procedure in the therapy of early ovarian cancer is surgery performed through a large abdominal excision, allowing the surgeon to inspect and stage the abdomen as well as the pelvis.
Where the disease is confined to the ovaries, Stage 1 disease, this may be curative on its own, but for higher risk patients in stage 1 (e.g. tumour rupturing through the capsule of the ovary) and all stage 2 cases, adjuvant chemotherapy is recommended. The term adjuvant therapy is used in cancer medicine to describe the administration of therapy, usually in the post-operative setting, to patients with no overt evidence of disease left following the operation, but who from risk factors are at high risk of later relapse. It has been demonstrated convincingly, for many cancers including ovarian cancer, that such therapy reduces this later relapse rate and that by giving the therapy early in the post-operative period rather than waiting for overt relapse to occur, the overall cure chance is increased.
The surgery usually involves the removal of the ovaries, the womb and the oviducts, as well as that covering membrane of abdominal contents, the omentum. Before the major surgery is carried out, the surgeon inspects the upper abdomen and samples the peritoneal surfaces at several sites to rule out stage 3.
Adjuvant chemotherapy is delivered to all but the earliest stage 1 patients in the post-operative setting and six courses of a regime of at least two drugs (e.g. carboplatin and paclitaxel) would be typical: the courses being three weeks apart. Most oncologists now divide early/stage 1 disease into low and higher risk stage 1 cases. Patients whose disease is low grade (or well differentiated - a histology term referring to the fact that the tumour's appearance down the microscope is to resemble the normal ovarian epithelium) have a very good prognosis, with a five year survival rate in excess of 90%. On the other hand, patient's whose disease is of higher grade fare worse, with those with intermediate grade histology (grade 2) having a five year survival of 77% and those with poorly differentiated disease (grade 3 histology) having a 55% five year survival. Obviously, this subdivision of stage 1 disease by histological grade has influenced oncologists as to whom they recommend chemotherapy: Thus, for patients with low risk, early stage disease, including stages 1A and 1B (intact capsule, no tumour excrescences and no malignant ascites or positive peritoneal cytology) surgery alone is recommended. However, for patients with higher risk disease: stage 1C (ruptured capsule, tumour excrescences, positive peritoneal cytology or malignant ascites) or high grade histology, adjuvant chemotherapy is now recommended.
In patients presenting with advanced stage 3 disease or stage 4 disease, there is no point in primary surgery and all to be gained by reducing the tumour ‘burden’ first by ‘cytoreductive’ chemotherapy. Chemotherapy (nowadays the first line drugs being a combination of taxol and a platinum can usually shrink the cancer down and make the ascites disappear and then, when the tumour has been shrunk right down, the surgeon resects any residual disease and removes those organs listed above.