Annual screening for ovarian cancer does not significantly reduce mortality

1. Both CA125 serum and transvaginal ultrasound annual screening did not significantly reduce deaths due to ovarian or tubal cancer compared to no annual screening.

2. The incidence of stage III-IV disease was decreased in the CA125 screening group compared to no annual screening.

Evidence Rating Level: 1 (Excellent)

Study Rundown: Ovarian cancer has a 5-year survival rate of greater than 90% if diagnosed at stage I. However, most diagnoses occur once the cancer has already metastasized and 5-year survival rates drop below 15%. Different annual screening tools, such as transvaginal ultrasounds (USS) and serum CA125 measurements (MMS), have been developed in hopes of increasing cancer detection. However, this randomized control trial of over 200 000 women in the UK did not find a significant reduction in mortality with annual MMS or USS screening compared to no screening. Interestingly, MMS increased detection of stage I disease compared to no screening, but this was not adequate to reduce mortality rates. While these results may indicate no benefit of annual screening in the general population, they have limited applicability to women at high-risk for ovarian cancer. Nonetheless, this study’s biggest strength was its large size and long follow-up period (16.3 years). While these results do not support the recommendation of annual ovarian cancer screening, more info is needed on the cost-effectiveness and feasibility of these screening methods to truly determine potential benefit in a clinical setting.

Click to read the study in the Lancet

Relevant Reading: Effect of Screening on Ovarian Cancer Mortality: The Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Randomized Controlled Trial

In-Depth [randomized controlled trial]: This randomized control trial was a continuation of the UK Collaborative Trial of Ovarian Cancer Screening (UKCTOCS), which recruited women aged 50-74 years between 2001 to 2005. 202 562 women were included in the final intention-to-treat analysis. Women were assigned randomly in a 1:1:2 ratio to an MMS, USS, and no screening group. The primary outcome recorded was death due to ovarian or tubal cancer by the study end-date of June 30^th, 2020. The mean follow-up time was 16.3 years. The MMS group had a higher incidence of stage I and II cancer detected compared to the no screening group, as well as a lower incidence of stage III and IV cancer. Between groups, the incidence of ovarian or tubal cancer was similar with 1% of patients in each receiving a diagnosis (MMS, 522 of 50 625; USS, 517 of 50 623); no screening, 1016 of 101 314). In total, there were 1206 deaths reported, with an equal percentage of women (0.6%) in each group being affected.

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