Leo Varadkar (Dublin West, Fine Gael) | Oireachtas source

First, in regard to CervicalCheck, a daily report and update is being provided by CervicalCheck on its website. That comes out at about 5 p.m. every day. If the Deputy goes to the CervicalCheck website, he will see it gives detailed guidance for GPs and smear takers as to what is happening and it gives them advice and guidance as to how they should communicate with patients who come to see them. That has been on the CervicalCheck website now for a number of days.

One of the aspects the inquiry will look into is absolutely that question to ensure and give us assurance that our cervical screening programme is up to international standard in terms of the accuracy, false positives and false negatives, and also to look at the issue of the different laboratories, labs, and whether there is a statistically significant difference in the number of false negatives identified in one lab versus the other labs. As the Deputy knows, three labs are used, two in Ireland and one in the United States. It is important once again to put on the record of the House the inherent limitations that exist in cancer screening. Screening tests are not diagnostic, nor are they designed to be; they are screening tests.

The whole idea or concept behind screening is that a patient is invited to come in long before they have any symptoms of cancer. By screening, one can pick up many cancers early before they become symptomatic, but one does not pick all of them up. Even the best test done by the best people will have a proportion of false negatives but those who are picked up early can get treatment earlier, which, of course, improves their outcomes and life expectancy immeasurably. We know from the Cochrane review, which was the highest level of clinical audit or study across the world, that roughly for every 1,000 women who go for a smear test, 980 can be given the all clear and assured that there are no abnormalities whatsoever, roughly 12 women will have abnormalities detected and can then go for colposcopy, which will prevent them from developing cancer or being diagnosed with cancer at that point, and eight will be false negatives. It is understood, therefore, that for every 1,000 smear tests, for every 1,000 women who goes through the door of their GP's surgery for a smear test, there will be a false negative in roughly eight out of 1,000 cases.

False negatives do not necessarily equal incompetence, negligence or failure on the part of the pathologist looking at the slides. It is understood that this is a limitation of cancer screening. We must bear in mind that in the clinical audit that was done, what is called retrospection bias would have been understood from day one. Essentially, when one looks at these slides under a microscope, one is looking at cells dyed with a coloured dye. One tries to see whether or not there are abnormal cells in the pattern. When the audit was done and they looked back at the 1,400 or so individual slides, they looked back with a different set of eyes. They looked back knowing that these women had already been diagnosed with cervical cancer. When one already knows the outcome and what one is looking for, one is more likely to find it. All of these things must be teased out in the period ahead both by the scoping inquiry, which started today, and the clinical review, which is being carried by the Royal College of Obstetricians and Gynaecologists.

See this speech in context