Can yearly blood tests reveal early-stage ovarian cancer?

The term "ovarian cancer" includes several different types of cancer that all arise from cells of the ovary. Most commonly, tumors arise from the epithelium, or lining cells, of the ovary. These include epithelial ovarian (from the cells on the surface of the ovary), fallopian tube, and primary peritoneal (the lining inside the abdomen that coats many abdominal structures) cancer. These are all considered to be one disease process. There is also an entity called borderline ovarian tumors that have the microscopic appearance of a cancer, but tend not to spread much.

Ovarian cancer accounts for about four per cent of all cancers in women. However it is a highly aggressive cancer and is one of the leading causes of death. Unfortunately early-stage ovarian cancer usually causes either no symptoms or very non-specific ones such as abdominal bloating, loss of appetite, dyspepsia and sometimes even urinary complaints. Therefore almost three fourths of women are diagnosed in the third or fourth stages. In these patients many effective treatment options are available including surgery, chemotherapy and targeted therapy. However, only a minority of these patients will be cured of their disease. The cure rate for early stage ovarian cancer is close to 90 per cent whereas it is less than 20 per cent for advanced stage patients.

Indian women are among the last ones to visit the doctor when it comes to their own health. This coupled with lack of awareness has been the major driver for ovarian cancer cases to increase. Because this condition usually occurs during menopause, most women ignore the symptoms, and further delay the treatment process.

A new way of screening for ovarian cancer appears to detect the disease in early stages, and if confirmed in clinical trials, the test could become a routine screening for women. In a recent study, researchers tested the screening on more than 4,000 women over an 11-year period. The women underwent yearly blood tests, and the researchers recorded the levels of a protein called CA-125, which is produced by the majority of ovarian tumors. Women who had sudden increases in CA-125 levels were referred to a gynecologist and were given an ultrasound.

On the basis of their ultrasound results, 10 women underwent surgery during the study period. It turned out that four women had ovarian cancers still in an early stage, and five others had ovarian tumors that were either benign, or of low malignant potential (tumors that may become cancerous, but usually do not). One woman had endometrial cancer, according to the study published today in the journal Cancer.  The study suggested that the testing strategy had a specificity of 99.9 percent, the researchers said, meaning that only 0.1 percent of patients without cancer would be falsely identified as having the disease.

The researchers are waiting for the results of a larger, randomized study currently being conducted in the United Kingdom that uses the same screening strategy. The results are scheduled to be released by 2015.