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 both 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 caases. 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 yeaar 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 oncolgists 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 – a point that has been difficult to persuade to the gynaecology profession. The fact is that chemotherapy (nowadays the first line drugs being a combination of taxol/paclitaxel and a platin (cis-platin or carboplatin) 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. With good initial staging and imaging, the number of failed primary attempts at surgery will go down. Where the surgeon enters the abdomen and cannot perform a definitive resection, then chemotherapy takes place and the surgeon goes back in later and carries out the definitive procedure; hopefully, in the future, the number of these failed primary surgical ‘debulkings’ will go down.
The chemotherapy has the predicted side effects: viz. hair loss, nausea in the early hours to days after its administration and the increased likelihood of infections between chemotherapy courses (which must be reported to the doctor and taken seriously with early antibiotic administration).
With such therapy, the results are that 75% of stage 1 and 50% of stage 2 patients survive five years. The survival for stage 3 patients is only 20% and for stage 4 patients at presentation only 5% at five years.
Radiotherapy has had a diminishingly important role in the therapy of ovarian cancer over the last two decades and is rarely used in the primary/radical therapy protocols. An antibody to a specific ovarian antigen and labelled with a radioactive isotope is a clever idea for targeting radiation therapy onto individual cancer cells, and such therapy exists. However, despite having been around for a decade it has not brought the promising results that had been hoped.
