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As ovarian cancer usually first makes itself apparent at a relatively late stage, the concept of screening to detect ovarian cancer at a relatively early stage is particularly attractive. There are two screening tests currently available for ovarian cancer ultrasound and a blood test for Ca125. Some ovarian cancers, but not all, are associated with an increase of a chemical in the blood called Ca-125. If a blood test shows a raised level of Ca125 there is an increased risk that there are cancer cells in the ovaries. The Ca125 level is raised (<35ku/l) in 80% of all ovarian cancers but in only 50% of patients with cancer confined to one ovary (Stage I0). False positive results of Ca125 can occur with endometriosis, benign ovarian cysts, pelvic inflammation and cancers from other sites. Other tumour markers are being evaluated. One new tumour marker, OVX1, has shown elevated levels when the Ca125 was giving a false negative result.
A fifty-three year old lady was known to have a fibroid uterus the size of a four month pregnancy. She arranged an ovarian screening Ca125 test at another hospital and the result was elevated. They recommended surgery but as we had previously known about the fibroid we managed to avoid an operation for her. Six years later on she remains well and the fibroid has become smaller as she has gone through her menopause. An ultrasound scan (pelvic ultrasound) may show a picture suggestive of cancer. The vaginal probe allows the picture to be seen from very close to the ovaries. Neither ultrasound nor the Ca125 tests can absolutely confirm or refute the possibility of cancer. It has been suggested that for every 10 women with a positive result, only one will actually have cancer. The limit of resolution for ultrasound is about 1 cm. For one malignant cell to multiply to reach the size of 1 cm requires 10 billion cell divisions. There is only another 1000 fold increase required to reach a weight of 1 Kg. Ovarian cancer screening is at an early stage of development so that there are as yet no large studies to confirm the potential benefits. In 1989, a committee in the UK assessed the situation and concluded that it was of unproven benefit and could not be recommended as a routine. An American committee came to a similar conclusion in 1994. Screening, therefore, remains an area for research. Some women have a family history of ovarian cancer. For women with no family history of ovarian cancer the cumulative risk of ovarian cancer by the age of 70 is about 1% and if there is one close relative with the disease the risk is about 3%. With two close relatives the cumulative risk may lie between 15 and 30%. For women in the UK in this high risk group screening is available in the National Ovarian Cancer Registry Screening Programme, which is organised from Addenbrooke's Hospital in Cambridge. There is a relationship between ovarian cancer and Breast Cancer Women with two affected close relatives with breast cancer before the age of 40 or one with ovarian cancer and one with breast cancer diagnosed before the age of 50 are also eligible. A genetic screen on a blood sample can identify women at increased risk. (Q32.40) Several hospitals have research interests evaluating screening the ovaries. If you feel that you may be at high risk they may be happy to screen you regularly. Screening is usually conducted annually.
Sadly, screening by CA125 and transvaginal ultrasound for ovarian cancer in high risk and low risk women has so far proven to be ineffective Related Medical Abstracts - Click on the paper title:-
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