Ultrasound fails to spot early ovarian cancer
Reported November 26, 2007
NEW YORK (Reuters Health) – Annual screening with a technique called transvaginal ultrasound, coupled with a blood test for CA125, a protein that can be elevated in the setting of ovarian cancer, does not reliably detect ovarian cancer early, at a more curable stage, according to a new study.
“We and other groups confirm that the current method of ovarian screening, which is a combination of ultrasound scans and (blood) markers, is ineffective,” Dr. Emma R. Woodward from Birmingham Women’s Hospital, UK, told Reuters Health.
“Therefore, for women at high risk of developing ovarian cancer, the only real option at present to prevent ovarian cancer death is to have the ovaries removed as a preventive measure.”
The early diagnosis of ovarian cancer is difficult and the disease is often not detected until it has reached an advanced stage.
In a “look-back” study, Woodward and colleagues assessed the effectiveness of ovarian cancer screening with the CA125 blood test plus transvaginal ultrasound, which involves placing an ultrasound probe into the vagina to detect abnormalities in the ovaries, in 341 women with a family history of ovarian cancer.
Out of 1,084 surveillance ultrasounds, 929 (86 percent) were normal and 155 (14 percent) were abnormal, the investigators report. Only 18 (2 percent) of 875 surveillance CA125 tests were abnormal.
Fifty-seven women (17 percent) had their ovaries removed as a preventive measure and 30 of the remaining women had “exploratory” surgery following abnormal surveillance ultrasound or CA125 testing.
Only four women developed ovarian cancer, the investigators report. Only one was detected at surgery for abnormal screening results and it was classified as advanced. In the other three cases, the women developed symptoms between screenings.
Based on these findings Woodward suggests that, for those women who are not at high risk for ovarian cancer, “ovarian cancer screening should not be offered unless it is within a clinical trial aimed at developing new methods for ovarian screening.”
“By entering such a screening program, healthy women may have exploratory surgery because of false-positive findings, thereby putting themselves at risk of potential surgical complications,” Woodward pointed out.
“Furthermore, the few women who do develop ovarian cancer are unlikely to be diagnosed at an early stage when the disease is curable.”
SOURCE: BJOG: An International Journal of Obstetrics and Gynecology, December 2007.