CA-125 Screening and Ovarian Cancer
Part 2: Commentary
by Carla Homan
This letter contains the usual misinformation, the kind you'll find in just about every Internet health scare. Take something true, sprinkle it with a little bit of hysteria and a lot of capital letters, add a smidgen of distrust for any doctor who might try to say otherwise, and wrap it in deception. Bake at 345 degrees for one hour or until crispy.
CA-125 is what is known as a tumor marker; it is used primarily to track the effectiveness of treatment for women who already have been diagnosed with ovarian cancer. It is also used, along with transvaginal sonography and regular pelvic exams, to screen for cancer among women determined to have a high risk of developing ovarian cancer. Unfortunately, CA-125 is an unreliable cancer screen. It returns a high number of false negatives (some ovarian cancers do not raise your CA-125 levels) and false positives (many benign conditions elevate your CA-125 levels).
Furthermore, studies indicate that CA-125 is even less reliable at detecting early-stage cancers than late-stage cancers. The email indicates that Carolyn Benivegna's CA-125 levels were elevated, but it also says that she was diagnosed with Stage III cancer. There's no way to know if her levels would have been noticeably elevated before her cancer progressed to this stage. She advises us, based on her own experience, to rely on CA-125 as a regular screen for early-stage cancer. But she offers no evidence that CA-125 is effective at that stage; even her own cancer had progressed past it by the time she was tested.
None of the following organizations recommend routine CA-125 screening for asymptomatic women who are not at high risk for ovarian cancer: American College of Physicians, the National Institutes of Health, American Cancer Society, National Cancer Institute, American College of Obstetricians and Gynecologists, American Medical Association, American Nurses Association, American Academy of Family Physicians, nor the American Medical Women's Association.
Aside from the misinformation about CA-125, there are some other troubling misrepresentations of the facts:
"Both types of cancer [ovarian and primary peritoneal] are diagnosed in the same way...and treated in the same way."
There are some types of ovarian cancer that do not necessarily call for chemotherapy and/or radiation; and not everyone has the same amount of surgery, depending on how far the cancer has progressed, and the patient's general health. Simply put, the claim that all ovarian cancers are treated the same way is false, and certainly the claim that they are all diagnosed with CA-125 is false, since the CA-125 alone cannot determine the presence of cancer cells.
"Please don't think youth will protect you, either. Though the median age for this cancer is 56... women as young as 22 have it. Age is not a factor."
Of course age is a factor when you're trying to decide whether certain tests are appropriate for you. Why do you think 22-year old women aren't given routine mammograms? Age is an important consideration when determining your risk level with any cancer, and that risk level helps you determine how far you need to go with screening and whether invasive or extreme or expensive tests (or, in the case of CA-125, terribly unreliable tests) are justified.
If you're still willing to accept medical advice from strangers on the Internet, here's some from me to you: stop accepting medical advice from strangers on the Internet and talk to your doctor for a change.
Update: Read the true story of Carolyn Benivegna's battle with ovarian cancer and how this email came to be written; also, a new statement by Ms. Benivegna correcting inaccuracies in her original message. See Laura Dolson's "The Truth About CA-125."
Sources and further reading:
Screening for Ovarian Cancer
Reliable information from WebMD.comAll About Ovarian Cancer
American Cancer SocietyOvarian Cancer Risk Factors
American Cancer SocietyDetection and Screening
American Cancer SocietyScreening for Ovarian Cancer
Columbia-Presbyterian Medical CenterSpecial Report: Tumor Marker CA-125
Andrew Holtz, Sapient Health Network
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