BreastCheck failing to meet targets on bringing women back for scans
BreastCheck, which provides free mammograms to women to pick up breast cancer, has refused to say if it has internal reports on patients who went on to develop the disease after the scan.
It is also unclear what the policy of BowelScreen, which tests for bowel cancer, is in relation to the release of look-back reports.
All screening programmes are overseen by the Health Service Executive's screening service.
Meanwhile, it has emerged that BreastCheck is failing the meet targets to invite 90pc of women back for a mammogram within 24 months.
The most recent report from BreastCheck for 2015-2016 shows that this recall target was only met in the case of 63.5pc of women.
It said that the percentage of women re-invited for screening within 27 months of their last invitation is at 94.4pc.
Women who had an abnormal mammogram result were offered a follow on assessment appointment within two weeks in 96pc of cases.
The percentage of women with cancer offered hospital admission within three weeks of diagnosis has risen in recent years and is above the standard of 90pc, according to its annual report.
BreastCheck uses digital mammography, but it has experienced some difficulty in recruiting enough specialist staff in recent years.
It offers the mammography scans to women aged 50 to 69 years.