Many women have turned up at cancer treatment clinics thinking they have ovarian cancer because a high level of the protein CA-125 has been detected in their blood.

However after going through a series of tests, the results show otherwise. Many health screening packages offer a blood test that measures the level of said protein in the blood - an abnormally high count is considered a sign of ovarian cancer.

Whilst some cases do turn out to be true, it is an inaccurate way to detect the cancer and should not be used in this way, said associate professor Jeffery Low, head of the gynaecologic oncology at the National University Cancer Institute, Singapore (NCIS).

A high level of CA-125 could also mean pregnancy, the presence of uterine or ovarian cysts -- both of which are non-cancerous conditions. Women who are on their menses or are ovulating also have more of the protein in the blood.

"Every week, we have people who get referred to us after they have the CA-125 test and they come in telling us, 'Doctor, I have cancer,'" said professor Low.

Professor Low mentions that in the weeks leading up to the appointment, many women face the mental stress of the possibility of earlier fatality. In addition, the stress of additional blood tests and scans, and even removing a healthy ovary in the worse-case scenario, is what these women have to go through. 

CA-125 test only for those who have been diagnosed


The CA-125 test is in actual fact, for monitoring women who have been diagnosed with ovarian cancer, he added.

If during diagnosis, the ovarian cancer patient is found to have high levels of CA-125, the blood test can be used to track the extent of the disease after treatment. An increase in CA-125, could mean that the cancer has relapsed.

The ovarian tumour can also be known as malignant or benign through the blood test. While there is no good way to screen for ovarian cancer, a good indication is looking at the family history of the disease. Women displaying symptoms of the disease, such as persistent abdominal bloating, swelling, pelvic pain, loss of appetite and breathlessness should also be taken note of.

However, using the CA-125 test itself as an indication of ovarian cancer is not advisable.

Early detection, better survival rates


But ovarian cancer does not display symptoms until later stages, which makes it the deadliest of all gynaecological cancers, said Dr. Tay Eng Hseon, medical director of the Thomson Women Cancer Centre. In Singapore, it affects approximately 350 per year, making it the 5th most common cancer amongst women.

Regular gynaecological checks are the only way to guarantee early detection and better survival rates. According to the United States National Cancer Institute, women with the BRCA1 mutation have a 39% risk of being diagnosed with ovarian cancer by age 70, while those who inherit the BRCA2 mutation, have an 11% to 17% chance.

NCIS has also found in an ongoing study that 30% of ovarian cancer patients in Singapore have this mutation, almost double the international rate. Many experts agree that women having fewer children, later in life is one of the reasons ovarian cancer is on the rise.

Less ovulation, less risk of ovarian cancer


"Developed countries tend to have a higher prevalence, because more women work, and so they have fewer children, and later in life," said Dr Chia Yin Nin, a gynaecology-oncologist at Gleneagles Hospital.

According to Dr John Chia of the National Cancer Centre Singapore, the risk is lowered when women ovulate less, therefore having more children protect women against ovarian cancer.

"When eggs are released, they rupture through the fallopian tubes, and that leads to some damage. So every time women ovulate, it opens the door to cancer cells and carcinogens," he said.

Of course, women cannot be constantly giving birth to set back the risk of ovarian cancer. Fortunately, going on the pill confers protection against ovarian cancer as well. In fact, consuming the pill for five years cuts the risk of getting ovarian cancer into half, said Dr. Tay.

The best way to prevent ovarian cancer is to "have two children, breastfeed, then go on the pill until the age of 45," he said. But for older women, the pill is not recommended as they could be at risk of getting deep vein thrombosis. If women are no longer planning to grow their family, a hysterectomy to remove the ovaries would be the best choice. MIMS

Read more:
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Sources:
http://www.straitstimes.com/singapore/going-on-the-pill-can-help-protect-against-ovarian-cancer http://www.straitstimes.com/singapore/health/blood-test-an-inaccurate-way-to-detect-the-cancer-expert
http://www.straitstimes.com/singapore/better-ways-to-tackle-womb-and-ovarian-cancers