Ovarian cancer screening does more harm than good reports government panel
In 2008, 21,204 women in the United States were diagnosed with ovarian cancer and 14,362 women in the United States died from ovarian cancer, according to the Centers for Disease Control and Prevention (CDC; 2008 is the most recent year statistics are available).
On September 10, another government organization, the United States Preventive Services Task Force (USPSTF), reported that screening tests for ovarian cancer such as blood tests and ultrasound examinations do not lower the death rate from the disease. The task force added that they yield many false-positive results that lead to unnecessary surgery with high complication rates. Their findings were published online in the Annals of Internal Medicine.
The panel stressed that their recommendation applies to healthy women with an average risk for ovarian cancer. It does not apply to women with suspicious symptoms or those at high risk because they carry certain genetic mutations (i.e., the BRCA mutations) or have a family history of the disease. The recommendations mark yet another challenge to cancer screenings issued by the USPSTF. Last May, it released a report in the Annals of Internal Medicine that the prostate specific antigen (PSA) test, which screens for prostate cancer, also did more harm than good. That recommendation prompted an outcry from physician groups, such as the American Urological Association (AUA), that the test was an appropriate screening method. However, the panels position regarding ovarian screening does have support from medical groups. The American Cancer Society and the American Congress of Obstetricians and Gynecologists (ACOG), have for years been discouraging tests to screen for ovarian cancer.
Some physicians routinely screen asymptomatic women with no increased risk factors for ovarian cancer. In addition, some patients request the testing. A report published last February in Annals of Internal Medicine, based on a survey of 1,088 physicians, reported that about a third of them believed the screening was effective and that many routinely offered it to patients.
Ovarian cancer is an insidious disease and usually does not produce symptoms in its early stages. When symptoms appear, it is usually at an advanced stage. Early symptoms include persistent bloating, pelvic or abdominal pain, feeling full early while eating, and needing to urinate frequently. Unfortunately, these symptoms can occur with other much less serious medical conditions.
The panel reviewed a large study published in 2011 in The Journal of the American Medical Association before arriving at its decision. The study comprised 78,216 women ages 55 to 74. Half were screened and half were not; they were then followed for 11 to 13 years. The screening consisted of ultrasound examinations and blood tests for elevated levels of CA-125, which can be a sign of malignancy. The researchers found no advantage to screening: the death rate from ovarian cancer was the same in the two groups. However, among the women who were screened, almost 10% (3,285 women) had false-positive results. Of those women, 1,080 had surgery, which usually involved the removal of one or both ovaries. Following the surgery, pathological examinations revealed that the no malignancy was present. At least 15% of the women who had surgery had at least one serious complication, such as a deep venous thrombosis (DVT; blood clot in the leg), infections, or surgical injuries to other organs. The report noted that to find one case of ovarian cancer, 20 women had to undergo surgery.
The problem with the screening tests is that CA-125 can be elevated by conditions other than cancer and ultrasound can reveal ovarian enlargement or cysts, which prove to be benign after removal.
Take home message:
The CA-125 test has an overall poor record because it can be elevated in a number of individuals who do not have cancer. If an enlarged ovary is noted on a routine pelvic examination an ultrasound can add valuable information. In general, benign and malignant ovarian growths have different ultrasound characteristics. Also, a repeat ultrasound at a later date can reveal whether the ovary has increased or decreased in size. Benign cysts may shrink; thus, indicating a benign condition. Most gynecologists will carefully analyze an abnormal finding on an individual basis. In some cases, the woman will push for the surgery. Another factor is a legal one. If a gynecologist opts for a repeat ultrasound at a later date rather than surgery, the woman may be the 1 in 20 who has ovarian cancer. A delayed diagnosis can incur a major malpractice liability.