ovarian cancer. &CA-125
ovarian cancer. &CA-125
Ovaries which are located on either side of the uterus in the lower abdomen, performs two main functions – (a) produce hormones (estrogen and progesterone) that are responsible for the development of secondary sexual characteristics and regulation of the reproductive cycle; (b) Develop and release an egg into the fallopian tube once a month during childbearing years.
Cancer of ovaries is the fifth most common cancer among women, and second most common gynecologic cancer and it causes more deaths that any other gynecologic cancer.
There are three types of ovarian cancer depending on the type of tissues, which become malignant: Epithelial, Germ cell tumors and Sex cord (stromal) tumors of which the epithelial tumor is the most common.
Symptoms with ovarian cancer are often vague. Women are more likely to develop symptoms after a stage where the disease has spread beyond the ovaries. Early-stage ovarian cancer also cause symptoms, but these symptoms also occur with many other conditions
Commonly the ovarian cancer expresses its presence with the following symptoms
? Abnormal menstrual cycles
? Digestive symptoms like constipation, increased gas, indigestion, lack of appetite, nausea and vomiting
? Feeling of pelvic heaviness and pain
? Swollen abdomen and lower abdominal discomfort
? Unexplained back pain that worsens over time
? Vaginal bleeding
? Increased urinary frequency
? Excessive hair growth
? Weight gain/loss
? Difficulty in eating
These symptoms are also common in women who do not have cancer. This is the reason for the late or poor prognosis of the disease
The cause of developing the disease is unknown and the risk factors for developing ovarian cancer appears to be several. We can put the risk factors together as follows:
? Old age women – About two-thirds of the deaths from ovarian cancer occur in women when they are diagnosed with ovarian cancer women at an age 55 and older. About 25% of ovarian cancer deaths occur in women ages 35-54
? Difficulty to conceive or Never being pregnant: The more children a woman has and the earlier in life she gives birth, the lower her risk for ovarian cancer.
? Personal or family history of cancer (Breast, colon, uterus or ovarian cancer).
? Women on estrogen replacement therapy (not with progesterone) for 5 years or more seem to have a higher risk of ovarian cancer. Recent studies suggest that birth control pills can decrease the risk of ovarian cancer and fertility drugs do not increase the risk for ovarian cancer.
? Certain genes (BRCA1 and BRCA2) are responsible for a small number of ovarian cancer cases
? An Eastern European (Ashkenazi) Jewish population shows an increased incidence of the disease.
Because the symptoms of ovarian cancer are subtle and non-cancerous conditions that can also cause similar symptoms, it is important to have regular checkups. There are no routine screening tests for ovarian cancer. Several tests including imaging and laboratory tests help to reveal ovarian cancer. New methods for early screening including ultrasound with blood test are being investigated.
A physical examination can reveal a swollen abdomen and fluid in the abdominal cavity sometimes suggesting a cyst or a tumor. Ultra sound that uses sound waves to create a picture of the ovaries, which is helpful in determining an ovarian cancer or a cyst.
Also biopsy of the tissues helps the diagnosis of the condition. The confirmation is generally drawn based on the results of blood tests that study several parameters like CA-125.
Cancer Antigen-125 is a glycoprotein encoded by MUC16 gene and is a best-known biomarker for ovarian cancer. It is also present on some normal tissues. This is a test approved by FDA for monitoring a woman’s response to ovarian cancer especially epithelial ovarian cancer. Approximately one-half of the patients who have localized (Stage 1) ovarian cancer and 90% of patients with advanced disease (Stages2-4) have increased serum concentrations of CA 125.
However elevated CA-125 levels have also been observed in many different conditions other than ovarian cancer like acute and chronic liver diseases especially in those which cirrhotic ascites, fibroid tumors, endometriosis, Pelvic Inflammatory Disease (PIDS), pacreatitis, lupus, pregnancy or other non-gynecologic problems. CA 125 is unreliable in screening pre-menopausal women because both ovulation and menstruation can cause elevated levels.
As a result, CA-125 cannot be a sole parameter for the screening of women for ovarian cancer. Also, it can return false negative results. Premenopausal women are more likely than postmenopausal women to receive a false positive CA-125.
The test should be repeated, more than once if necessary to avoid unnecessary surgery. Normalization of CA 125 values is a condition but not a guarantee for regression of the disease, since patients with a normal CA 125 may have progression of the disease. A rise in CA 125 during or after treatment, however, is almost always associated with progression of the disease. The lack of specificity of CA 125 for ovarian cancer has not hampered the use of the test in the clinical management of patients with this disease. Initially, the CA 125 test was approved for use postoperatively in patients to determine the likelihood that tumors would be found at a second-look operation. If the CA 125 value was increased after debulking surgery and completion of required courses of chemotherapy, residual disease was likely present and the patient would not benefit from this additional surgery. Since a “normal” CA 125 value would not indicate the absence of disease, a second-look operation to confirm the disease status was recommended. Today, however, the use of second-look surgery is controversial, and a recent NIH Consensus panel has recommended the use of serial CA 125 testing in lieu of second-look surgery, at least for those women with a preoperative increase of CA 125. The combined use of CA 125, physical and pelvic exam, and transvaginal ultrasonography can detect disease progression with 90% sensitivity. An optimal monitoring protocol has not been recommended, but suggested practice is to perform CA 125 testing every 3 to 4 months for 2 years post treatment, and regularly but less frequently thereafter.
A developing role for the serum CA 125 test is that of assessing response to chemotherapy. Data supportive of treatment response is important for continuing a toxic therapy, especially for patients who have no clinically detectable disease. On the other hand, data indicating treatment failure can prompt early discontinuation of an expensive, non effective therapy and provide the opportunity for salvage therapy or participation in a clinical trial of a new treatment.
REF-health screen april2011