Patient Symptoms Inadequate Way to Diagnose Ovarian Cancer
Posted Feb 05 2010 12:00am
One of the challenges of malignant neoplasms like ovarian and pancreatic cancer is that the early signs and symptoms are either absent or nonspecific. A recent article that discussed this problem for ovarian cancer is not encouraging (see: Symptoms Poor Indicators Of Ovarian Cancer, Study Finds). Below is an excerpt from it:
Only about 1% of women who experience symptoms of ovarian cancer, such as persistent bloating or pelvic pain, actually have the cancer, according to a study published Thursday in the Journal of the National Cancer Institute.... Lead author Mary Anne Rossing...said, "What this (study) suggests is that it's going to be hard to move the diagnosis of ovarian cancer forward." Many medical societies recommend the use of these symptoms to aid early detection of ovarian cancer, but the study found no evidence that the symptoms could lead to earlier detection. About 14,000 women die from ovarian cancer annually in the U.S., and it is estimated that one in 2,500 women has the disease without knowing it. Experts do not advise routine ovarian cancer screening for the general population because of a high rate of false positives and risk for unnecessary surgeries....The study noted that 100 women who report having symptoms would need to be examined to detect one cancer. It also found that among the women who did not have cancer, 6% had persistent symptoms. However, because the disease is rare, these women are unlikely to have it, the study said. The findings support "a cautious approach to the use of symptom patterns to trigger extensive medical evaluation for ovarian cancer," the researchers wrote.
This is not good news. The conclusion is that only a very small percentage of women who experience the symptoms of ovarian cancer actually have the disease. If you can't depend on the appearance of symptoms to prompt physician visits by patients with the disease, what's left? Routine imaging for screening purposes is not an option -- the disease does not have a sufficiently high prevalence to justify this approach. It seems to me that the only answer is the development of an effective IVDMIA (i.e., biomarker panel) to screen for the disease. About two years ago I posted a note about a multiplex test to screen for ovarian carcinoma (see: Encouraging Results from LabCorp/Yale Multiplex Lab Test for Ovarian Cancer). This created a firestorm of criticism regarding lack of FDA approval for the test (see: F.D.A. Says Cancer Test Failed to Get Its Approval).
It appears that little progress has been made since that time in the development of screening tests for ovarian cancer. Here's a quote from the American Cancer Society web site:
CA-125 is a protein in the blood that is higher in many women with ovarian cancer. The problem with this test is that conditions other than cancer can also cause high levels of CA-125. In addition, someone with ovarian cancer can still have a normal CA-125 level. When a CA-125 level is abnormal, many doctors will repeat the test....The doctor may also consider ordering a transvaginal ultrasound test. In studies of women at average risk of ovarian cancer, these screening tests did not lower the number of deaths caused by ovarian cancer. This is why transvaginal sonography and the CA-125 blood test are not recommended for ovarian cancer screening of women without known strong risk factors....Ways to improve ovarian cancer screening tests are being researched. Hopefully, further improvements will make these tests effective enough to lower the ovarian cancer death rate.