March 10 (HealthDay News) -- Used together, a blood test and an ultrasound scan may be effective in detecting ovarian cancer in its early and more curable stages, British researchers report.
The two-step detection method could become a new standard in the fight against this deadly and hard to spot malignancy, experts say.
"It appears to be an approach that may be workable," said Robert Smith, director of cancer screening at the American Cancer Society.
The report was published in the March 10 online edition of The Lancet Oncology.
Experts note that, when found early, ovarian cancer is 90 percent curable. But early detection is often impossible, because the disease causes few or no symptoms as it begins. For that reason, 70 percent of cases of ovarian cancer are diagnosed when the cancer has already reached an advanced stage.
In these later stages, the survival rate drops to only 20 percent to 30 percent. For that reason, scientists and doctors have long sought an effective early screening test.
The new study was led by Dr. Usha Menon, head of the Gynaecological Cancer Research Unit at University College London. The team randomly assigned almost 203,000 postmenopausal women to either no ovarian cancer screening or to screening with transvaginal ultrasound plus a blood test that finds a marker for ovarian cancer, called CA125. A third group was screened using transvaginal ultrasound alone.
Between 2001 and 2005, the researchers uncovered 87 ovarian cancers. The specificity of the tests was best in the combined screening group. In that cohort, fewer retests were needed and almost ninefold fewer surgeries were required, the researchers noted.
The team found that screening was able to identify most women with cervical cancer. The combination of the blood test and ultrasound found 90 percent of the cancers, while ultrasound alone found 75 percent of the cancers.
Almost 50 percent of all the cancers found were in an early stage (stage I or II), the researchers noted. And 48 percent of the more invasive ovarian cancers detected were designated as being stage I tumors. Usually, only 28 percent of ovarian cancers are identified in this early stage, the researchers pointed out.
To see whether these screening strategies have an impact on mortality, the women will continue to be screened through 2012 and followed until the end of 2014, the researchers said.
Menon stressed that it's too early to make firm recommendations based on these early findings.
"Preliminary results are encouraging," she said. "Both types of screening can be used on a large scale, and both successfully pick up ovarian cancers. But for a final answer as to whether ovarian cancer screening will save lives, we need to wait till 2015, when the trial will be finished."
For his part, the ACS' Smith said that experts have learned to be cautious when it comes to advocating a particular screening method for ovarian cancer.
"What we have is a long line of disappointing findings using either CA125 alone or ultrasound alone," he explained. But he added that, "in combination, the performance appears to be much better."
Although some women are getting these tests in the United States, women should not be asking to get these tests based on this preliminary data, Smith said. "Right now, the only group of women that is recommended to undergo any testing for ovarian cancer are women who are at very high risk due to family history," he said.
"This screening trial is both a test of whether we can actually deliver these tests and whether we have shown better survival. But more importantly, have we shown that there is a lower rate of ovarian cancer deaths?" Smith said.
SOURCES: Usha Menon, M.D., head, Gynaecological Cancer Research Unit, University College London, U.K.; Robert Smith, Ph.D., director, cancer screening, American Cancer Society, Atlanta; March 10, 2009, The Lancet Oncology, online