UK Collaborative Trial of Ovarian Cancer Screening

UKCTOCS aims to assess whether ovarian cancer screening will save lives while comprehensively evaluating the screening strategies available, the worry and complications associated with screening and ensuing surgery, compliance and the potential resource implications for the NHS. Women aged 50-74 in 13 regions in the UK were invited to take part. The 202,638 women who joined the study were randomly allocated to an observation (control) group or screening with transvaginal ultrasound (USS)for 6 years or screening with a blood test called CA125 for 6 years. All women are being followed up by postal questionnaire and through the Office for National Statistics to establish whether or not they develop ovarian cancer or die of the disease. Screening is ongoing and the study has met all its targets on recruitment, retention and follow up. Currently each woman is in the trial for 7 years from randomisation and the trial will be complete in 2012. Hoever, it is now clear that there are less deaths from ovarian cancer than expected in the women in the control group who have not been screened. As a result of thos healthy volunteer effect the trial needs to be extended to obtain a clear answer to the question - Can ovarian cancer screening save lives? The best approach will be to extend screening until 2011 and follow up everyone until 2014.

UKCTOCS is a RCT to assess impact of screening on ovarian cancer mortality while evaluating performance characteristics of screening, physical and psychological morbidity, compliance and resource implications. Women aged 50-74 were invited from 27 Primary Care Trusts adjoining 13 trial centres. Women who accepted were invited to recruitment and 202,638 were randomised to an observation (control) group or 6 annual screens with transvaginal ultrasound (USS)or serum CA125 (M)in a 2:1:1 ratio. All women are being followed up by postal questionnaire and ?flagging? through the Office for National Statistics. Screening is ongoing and the study has met all its targets for recruitment, retention and follow up. Currently each woman is in the trial for 7 years from randomisation and the trial will be complete in 2012. It has now become clear that the number of age adjusted observed deaths (OD) in UKCTOCS participants is significantly reduced compared to expected deaths (ED), based on ONS mortality statistics. The overall Standardised Mortality Ratio (SMR - ratio of OD/ED expressed as a percentage) is 31.6 and for ovarian cancer is estimated at 65. As a result of this healthy volunteer effect, there will be a shortfall in power. An extension is therefore requested to compensate for this effect. Various options have been explored to increase events in the control arm. The favoured option based on cost and time to trial completion is extending trial participation to the end of 2014 with all women in the screened arm undergoing screening till end of 2011.