21st June 2023

Ovarian cancer

Cancers of the ovary are subdivided into the cell of origin. The majority are epithelial in origin, and this also encompasses malignancies of the Fallopian tube and peritoneum. Epithelial cancers are further subdivided into serous carcinoma, endometrioid (linked to endometriosis), clear cell (also linked to endometriosis) and mucinous. The latter should be differentiated from metastatic spread from a mucinous gastrointestinal primary and typically the appendix is resected during surgery to rule this out as a primary site.

Germ-cell tumours are less common but should be suspected in patients presenting at a young age. These can be divided into benign tumours (e.g. mature teratoma) and malignant tumours including dysgerminomas (the ovarian equivalent of seminomas), yolk sac tumours and choriocarcinomas.

Sex-cord stromal tumours are rare entities, making up 5% of ovarian cancers. They originate from the supportive structures of the ovary and can be functional, secreting excessive androgens and oestrogens. Therefore, these may present with dysfunctional menstrual bleeding, post-menopausal bleeding, and breast tenderness.

In those with suspected cancer, the Risk of Malignancy Index (RMI) is employed. This is calculated using the formula RMI = CA125 x U x M. CA125 is a serum tumour marker which is non-diagnostic but is often raised in ovarian malignancy. U confers a score based on ultrasound features, with 1 point for each of the following characteristics: multilocular cysts, solid areas, metastases, ascites, and bilateral lesions. U = 0 (for an ultrasound score of 0), U = 1 (for an ultrasound score of 1), and U = 3 (for an ultrasound score of 2 to 5). M confers the menopausal status, with a score of 1 for pre-menopausal patients and 3 for post-menopausal patients. Referral onwards for specialist review should be triggered in those patients with an RMI of 250 or more.

Treatment for ovarian cancer is typically with surgery, guided by the extent of the disease, ranging from a simple oophorectomy, to total macroscopic clearance of disseminated disease, as well as exenterative surgery. Neoadjuvant or adjuvant chemotherapy is guided by the staging and characteristics of the underlying malignancy.