Long term impact of screening on ovarian cancer mortality in the UKCTOCS

Screening may help save lives by detecting ovarian cancer earlier

LSE Principal Investigator: Alistair McGuire
Start Date: 01 January 2017
End Date: 15 June 2021
Regions: Europe
Countries: England, Wales, Northern Ireland
Keywords: Ovarian cancer, gynaecology, screening, postmenopausal


Ovarian cancer is the leading cause of death from gynaecological cancers in the UK. This is related to diagnosis at advanced stage. When women are diagnosed earlier, they have a much better survival – over 90% of Stage I patients are alive five years after diagnosis compared to 4% of Stage IV patients. This suggests that screening may help save lives by detecting the disease earlier.

The United Kingdom Collaborative Trial of Ovarian Cancer Screening (UKCTOCS) was designed to test this hypothesis. Between April 2001-Sept 2005, 202,638 postmenopausal women, aged 50-74 years were recruited through 13 trial centres in England, Wales and Northern Ireland.

Women were randomly allocated to one of three groups (i) control (C ) - no screening (ii) multimodal screening (MMS) - annual blood test for serum CA125 measurement. The results were interpreted using the ‘Risk of Ovarian Cancer Algorithm’, with transvaginal ultrasound as a second line test in case of abnormality (iii) ultrasound screening (USS) – annual and second line tests were transvaginal scans.

Women in the screen arms underwent a total of 673,765 annual screens till 31st December 2011. On 31st Dec 2015 at a median follow-up of 11.1 years per woman the initial mortality analysis was undertaken. Compared to the control group there was significant increase in number of women diagnosed with early stage ovarian cancer in the multimodal but not in the ultrasound group. The average reduction in ovarian cancer deaths was 15% in multimodal group and 11% in ultrasound group compared to control but this was not definitive. The final extent of reduction remains to be determined as the ovarian cancer death rates were increasing in the control group and levelling off in the multimodal and ultrasound groups.

A second analysis of impact on ovarian cancer mortality and cost effectiveness will be undertaken following censorship in mid-2020. These results are likely to be available in January 2021.

Follow-up will continue till 2024.

Outputs for download:

(2021) Article: Ovarian cancer population screening and mortality after long-term follow-up in the UK Collaborative Trial of Ovarian Cancer Screening (UKCTOCS): a randomised controlled trialThe Lancet. 

Click here to view online.

(2021) Briefing paper: Does annual ovarian cancer screening reduce deaths among women in the general population? 

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