In a large multicenter study enrolling over 70,000 women, annual screening with transvaginal pelvic ultrasound and ca125 blood testing did not reduce deaths from ovarian cancer, and in fact led to an increase in complications due to screening.
Investigators in the NCI-sponsored Prostate, Lung and Ovarian Cancer (PLCO) Screening trial randomly assigned over 78,000 women age 55-64 years of age to either annual screening with transvaginal pelvic sonograms for 4 years plus CA125 testing for 6 years or usual care at 10 study sites across the US., and followed the groups for up to 13 years. Over that time period, ovarian cancer rates in the screened group were 5.7 per 10,000 person-years vs 4.7 per 10,000 persons-years in the usual care group, with 3.1 deaths vs 2.6 deaths per 10,000 person years, respectively. Over 3000 women had false positive screening results, a third of whom had surgery and 15% of those operated on had a complications from their surgery. Deaths from other causes did not differ between the groups.
The investigators concluded that annual screening for ovarian cancer does not reduce mortality, and in fact caused harms among women with fals positive abnormal results.
This is not the first study that failed to find efficacy for ultrasound and ca125 in reducing mortality from ovarian cancer, but it is certainly among (if not ) the largest.
Whether or not more frequent sonogram screening, combining ca125 with other serum markers, or trending ca125 levels over time (rather than just looking for “abnormal” results) will prove to be effective ovarian cancer screening has yet to be determined. Studies continue to be done, although preliminary results to date on these have not been encouraging.
What I do in My Practice
I tell my asymptomatic, low-risk patients who ask me for ovarian cancer screening that annual sonograms are like kissing the Blarney Stone. It makes us all feel lucky for awhile, but actually does nothing to reduce ovarian cancer mortality.
Still, I have not refused occasional screening for anxious women (Often women who have had a friend recently diagnosed with ovarian cancer), so long as they understand the limitations of screening, but seem to need that negative sonogram to sleep at night. I do respect their anxiety, and if that means an occasional scan in the office and a reassured patient, I don’t see much harm, and they are told up front that their insurance may not cover the scan. I also happen to refer to a great radiologist who does not overcall abnormals, so if I see anything of concern, I refer straight to him. Now that we have this data regarding adverse outcomes due to over-screening, I will share that with my patients, and may be able to stand a bit more firmly in refusing to order ineffective screening to asymptomatic but anxious women.
For women at increased risk (family history of ovarian cancer, BRCA gene mutation carriers), I do offer vaginal sonogram and ca125 screening, but at minimum of twice a year, and urge these women to instead enroll on one of the several ovarian cancer screening trials currently in progress.
*This blog post was originally published at The Blog That Ate Manhattan*