The Royal College of Obstetricians and Gynaecologists "is certain" that the inclusion of 35 missing slides in its review of the CervicalCheck controversy would not have made a “material difference” to its findings.
The review found “missed opportunities” to prevent or diagnose cancer earlier in some women but, overall, the Irish screening programme is performing effectively.
At a meeting of the Oireachtas committee on health, Solidarity-People Before Profit TD, Bríd Smith, said many of the missing slides had serious misreadings.
The findings of the RCOG review of 1,038 slides were found to be similar to a much larger slide review involving cases of cervical cancer in England.
The RCOG's lead assessor, Prof Henry Kitchener, told the committees he did not believe the inclusion of the missing files would have made a material difference.
“I don't think these slides as a sample would be qualitatively different from the very large sample that we reviewed. In other words, the ratio of concordant and discordant findings would not have been any different,” said Prof Kitchener.
We would have liked every single slide to be available for review but the fact that some were not I don't think would have altered our conclusions.
But Ms Smith persisted in questioning Prof Kitchener and asked if he could say “for sure” that the slides would not have made a difference.
“I am certain that those missing slides would not have materially affected our conclusions,” he responded.
What he was certain about was that they would not have altered the conclusion of their “aggregate” report.
“It may have altered the detailed content of individual letters because it may have allowed us to include that slide in our determination.”
Prof Kitchener also said it was a “remarkable coincidence” that the slides of two prominent cervical cancer campaigners became mixed up.
Labour's health spokesperson Alan Kelly asked how could it happen “statistically” to two such well-known women – Vicky Phelan and Lorraine Walsh.
The committee heard that temporary labels were taken off and put back on following completion of the review after slides had been put into boxes and sealed.
“That would appear to be a remarkable coincidence but the one key point here is that this labelling issue, as you (Mr Kelly) refer to it, took place following the completion of the review and, therefore, it had no impact whatsoever on the actual conduct of the slide review,” said Prof Kitchener.
Chief medical officer at the Department of Health, Dr Tony Holohan, said the mislabelling was “surprising” but his understanding was the identity of any individuals was not known.
Interim national director of the HSE national screening service, Damien McCallion, said he had explained the “unfortunate set of circumstances” that led to the mislabelling in a letter sent to all of the three women affected.