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Jacobs IJ, Skates SJ, MacDonald N, et al. Screening for ovarian cancer: a pilot randomised controlled trial. Lancet. 1999 Apr 10;353:1207-10.
In postmenopausal women, what is the feasibility and effectiveness of ovarian cancer screening?
Randomised (concealed), unblinded, controlled trial with 7-year follow-up.
Women who were 45 years of age and were postmenopausal. Exclusion criteria were history of bilateral oophorectomy or ovarian cancer. 22 000 women were invited to participate; 21 935 were randomised. All participants were traced through the National Health Service Central Register and the Family Health Services Authority.
Women were allocated to annual screening for ovarian cancer for 3 years (n = 10 958) or to follow-up with no screening (n = 10 977). Initial screening involved measuring serum CA 125 antigen. Women with CA 125 of 30 U/mL were recalled for pelvic ultrasonography. Women with abnormal ultrasonographic results (ovarian volume 8.8 mL) had a repeat scan to confirm the findings and were then referred for surgery.
Main outcome measures
Incidence of index ovarian cancer and mortality.
Of 10 958 women allocated to screening, 9364 (86%) completed 1 screen. Of 29 women who had surgical investigation, 6 had an index cancer. The positive predictive value of screening was 20.7%. 10 more women in the screening group developed cancer during follow-up. 20 women in the control group de veloped cancer. Among the women who developed cancer, survival was longer in those who received screening than in those in the control group (73 vs 42 mo, P = 0.011), but mortality from index cancers did not differ between the groups (P = 0.083) (Table).
In postmenopausal women, ovarian cancer screening was feasible and had a positive predictive value of 21%. Survival was longer in women who were screened, but no difference in mortality was seen between screened and control groups.
Sources of funding: Research into Ovarian Cancer; Gynaecology Cancer Research Fund; Dana Farber/Partners Cancer Program; National Cancer Institute.
For correspondence: Mr. I.J. Jacobs, St. Bartholomew's Hospital, London EC1A 7BE, England, UK. FAX 44-171-601-7652.
Screening vs no screening for death from index ovarian cancer at 7 years
Screening No screening RRR (95% CI) NNT
0.08% 0.16% 50% (9 to 77) Not significant
*Abbreviations defined in Glossary; RRR, NNT, and CI calculated from data in article.
Jacobs and colleagues conclude that screening for ovarian cancer with serum CA 125 followed by pelvic ultrasonography is feasible and justifies a larger randomised trial to assess the effects on mortality. However, despite this trial, the benefits of population-based screening for ovarian cancer remain uncertain.
The study participants were a highly motivated group of volunteers recruited from a previous study. 86% of participants completed at least 1 screen. The applicability to a more general population is unknown. Although the study showed an increase in median survival, no increase in overall survival was found. The authors note that the study was of insufficient size to show a survival advantage. In the approximately 11 000 women in the screened group, only 6 of 16 cases of index cancer diagnosed were found as a result of screening. In contrast, annual faecal occult blood testing for colorectal cancer screening results in an estimated 130 lives saved per 10 000 patients screened (1).
Ovarian cancer is a relatively rare disease, with an incidence of 11.2/100 000 in North America (2). The problems inherent in screening diseases of low prevalence have been shown in a decision analysis on the effectiveness of screening for ovarian cancer by Schapira and colleagues (3). Average life expectancy in a population of screened women 65 years of age was estimated to increase life by only three quarters of 1 day of life. Given the small potential benefit for women with average risk, it seems that screening for ovarian cancer should be deferred at this time.
Robert Gluckman, MD
Providence-St. Vincent Hospital
Portland, Oregon, USA
1. Winawer SJ, Fletcher RH, Miller L, et al. Colorectal cancer screening: clinical guidelines and rationale. Gastroenterology. 1997; 112:594-642.
2. Landis SH, Murray T, Bolden S, Wingo PA. Cancer statistics, 1999. CA Cancer J Clin. 1999;49:8-31,1.
3. Schapira MM, Matchar DB, Young MJ. The effectiveness of ovarian cancer screening. A decision analysis model. Ann Intern Med. 1993;118:838-43.
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