The preliminary results of the most extensive randomised trial of ovarian cancer screening so far, are published Online First and in the April edition of The Lancet Oncology. The findings indicate that detecting early stage ovarian cancer is possible with the CA125 blood test and transvaginal ultrasound, with almost half of the cancers in stage I/II.
More than any other cancer of the female reproductive system, ovarian cancer is to blame for more deaths, often referred to as “the silent killer”. It is 90 percent curable when detected in the early stage (when limited to the ovary). Seventy percent of ovarian cancers are diagnosed at an advanced stage with only a 20 to 30 percent rate of survival because of the lack of early symptoms. For the moment, the early stages of the disease are not detected in the screening tests.
The latest advances in screening tests indicate that scanning for ovarian cancer could now be possible with transvaginal ultrasound and the development of a risk score to interpret the results of the blood test for the tumour marker CA125.
In order to find out more, Ian Jacobs and Usha Menon, University College London, UK, and their team, carried out the United Kingdom Collaborative Trial of Ovarian Cancer Screening (UKCTOCS). They evaluated the consequences of ovarian cancer screening on mortality and the efficacy of two screening strategies: Multimodal screening (CA125 blood test combined with transvaginal ultrasound) and ultrasound screening. The women participating in the research will be screened up to the end of 2012 and then monitored for two more years. The authors will inform on the sensitivity and specificity of the first screen.
Through twenty seven regional Primary Care Trusts across the UK, 202,638 post-menopausal women, aged between 50 and 74, were recruited between 2001 and 2005. The women were randomly selected to receive no treatment (control group), to receive multimodal screening (MMS) every year, or to be screened with transvaginal ultrasound (UUS) annually in a 2:1:1 ratio. Patients showing consecutive atypical screens were given a clinical evaluation and underwent surgery.
The results indicate that the screening program was successful in detecting the majority of ovarian cancers, with 90 percent (34/38) using the MMS strategy and 75 percent (24/32) using the USS strategy. Nearly half of the cancers that were identified were in stage I/II. Twenty four out of fifty eight invasive cancers were detected in stage I, with fourteen in the MMS group and ten in the USS group. The researchers indicate that the fact that 48 percent of stage I invasive ovarian cancers were detected is very promising, since usually only about 28 percent of invasive cancers are detected at this early stage in most ovarian cancer series.
In the different screening groups, the total number of cancer cases that were identified (eighty seven primary ovarian and three tubal) was similar (forty two in the MMS group and forty five in the USS group). The researchers pointed out that specificity was considerably improved in the MMS group. This resulted in fewer repeat tests and reduced the number of surgeries per detected cancer by almost nine times (35.2 operations in the USS group, compared with 2.9 in the MMS group).
The researchers say that the findings show promising results in both screening strategies and are feasible on a large scale. “Analysis of the psychosocial impact and cost effectiveness of these strategies is currently underway. The results of ongoing screening are required before a conclusion can be drawn regarding the effect of screening on mortality,” they conclude.
The Lancet Oncology
Written by Stephanie Brunner (B.A.)