About CA-125
CA-125 (measured by a blood test) is considered an important tumor marker for epithelial ovarian cancer. More than 90% of advanced ovarian cancer patients have CA-125 levels above 30 U/mL. However, many women without cancer may experience elevated CA-125 levels.

What is a Tumor Marker?
A tumor marker is a substance (usually a protein) that the body produces in response to cancer. While some tumor markers are cancer-specific, many markers appear in noncancerous conditions as well.

How Are Tumor Markers Used?
Screening
Tumor markers usually are not used by themselves in screening for the early signs of cancer.

Detecting recurrence
Tumor markers can be a helpful instrument in determining recurrent disease when repeated on a regular basis and in combination with other tests.

Monitoring treatment
After treatment, it may be useful to test for some tumor markers. In order to adequately assess your condition, the results of any tumor marker test will be carefully considered by your doctor along with your medical history, physical examination and additional radiologic tests.

What Does a Rise in CA-125 Mean?
A single CA-125 test is never definitive. A serial rise, or continuous rise, over a period of time is much more reliable in monitoring your response to treatment. Regular testing will provide a more consistent and more accurate pattern of your levels.

Serial testing of CA-125 may be useful during therapy for recurrent ovarian cancer. Because some people may have a rising CA-125 at the beginning of therapy, your levels may be measured periodically during treatment to establish a reliable pattern.

It is important not to measure the effectiveness of your treatment by a single CA-125 test. A rise in CA-125 does not necessarily mean that your current treatment isn’t working. Work with your healthcare team to understand what tests are being used to evaluate your progress.

What Other Tests May Accompany the CA-125 Test?
Remember that while tumor markers such as CA-125 may be used in the process of diagnosis and subsequent treatment decisions in recurrent ovarian cancer, it is not often used as the sole tool for screening or monitoring treatment response. The serial CA-125 test is more indicative of your response to treatment when combined with some or all of the following:

• Ultrasound
• Pelvic examination
• Imaging studies (CT scans, MRI, PET)
• Biopsy specimens (sample tissue removed from the body)
• Chest X-rays

Questions to Ask Your Doctor or Nurse

1. What tumor markers will be monitored during my treatment?
   
   
2. How will you use these markers?
   
   
3. How often will I be tested?
   
   
4. What other diagnostic measures will be used along with tumor markers to assess my response to therapy or confirm disease progression?
   
   
5. How will the decision be made if and when my current therapy needs to change?