Screening Asymptomatic Women for Ovarian Cancer:
American College of Preventive Medicine
Practice Policy Statement
Evidence of effectiveness
Sensitivity of pelvic examination for detection of ovarian cancer is unknown; however, it is thought to be quite low due to the anatomic location of the ovary. Cancers detected by pelvic examination are often far advanced. Ultrasound is widely used for diagnostic testing for pelvic masses, but is limited in its usefulness as a screening tool by high rates of false-positive results and low positive predictive value. One study reported a relatively high sensitivity (100%) and specificity (94.6%) of routine ultrasound of asymptomatic women, but positive predictive value was low (2.6% ). (6) Because transvaginal ultrasound
provides a higher level of detail than transabdominal ultrasound, it maintains a higher sensitivity (100%) and allows a higher specificity (98.7%) for ovarian cancer. (7) However, due to high rates of false-positive interpretations, positive predictive value is still low (22%). (8) Color flow Doppler imaging, in combination with transvaginal ultrasonography
, improves specificity and ability to discriminate benign and malignant tumors, but its value in screening is unknown.
Studies on the effectiveness of ultrasound for screening are limited by small sample sizes, limited follow-up, and the use of nonrandomized volunteers. Routine ultrasound screening of asymptomatic women generates a high proportion of false-positive results, which require laparoscopy or laparotomy. One study of 805 high-risk women yielded 39 laparotomies, 1 ovarian cancer, and 8 other tumors (2 borderline tumors, 1 cecal cancer, 5 cystadenomas). (10) Another study of 5,489 asymptomatic women with or without a family history of breast or gynecologic cancer reported the detection of 5 cancers in 14,356 ultrasound screens performed over 3 years. (11) It has been estimated that ultrasound screening of 100,000 women over age 45 would detect 40 cases of ovarian cancer, with 5,398 false-positive results and more than 160 complications from laparoscopy. (12)
Biochemical markers, particularly CA 125
, are useful in monitoring patients with ovarian cancer and have been suggested for screening, either alone or in combination with ultrasound. Although CA 125 is detectable in 80% of epithelial ovarian cancers, (13) it is elevated in less than half. (14) Following a single elevated CA 125 measurement with abdominal ultrasound yielded a sensitivity of 58%-79%, specificity approaching 100%, and positive predictive value of 27% in one series. (14) Molecular biomarkers, such as BRCA1, a genetic marker for familial breast/ ovarian cancer syndrome, may be useful in certain cases for detection of those at particularly high risk of ovarian cancer; however, use is still experimental.
The high association between stage of diagnosis and survival from ovarian cancer suggests that screening or early detection could decrease mortality association with ovarian cancer
, but the role of lead and length-time bias remains unresolved. However, to date, no large-scale, prospective randomized trial with adequate follow-up comparing screening modalities to clinical observation has been completed. Such an investigation is underway, under the auspices of the National Institutes of Health (NIH) as part of the Prostate, Lung, Colorectal, and Ovary randomized clinical trial comparing CA 125 and transvaginal ultrasound screening to routine care.
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