Fourteen women suffered a delayed diagnosis of breast cancer because of "sub-standard care", an inquiry has reported.
The review was carried out on the work of a radiologist, now suspended, and involved up to 8,000 screenings at three main hospitals across Northern Ireland. They are Belfast City Hospital, Altnagelvin hospital in Derry and the Antrim area hospital.
The mammograms of 404 women were reassessed following the suspension of the radiologist. Of that number, 14 breast cancers were detected but there was a delay in diagnosis which was not picked up at earlier stages.
The independent report, carried out by Dr Robin Wilson, director of Breast Screening Quality Assurance in the English east Midlands, said another four developed cancer before the review began.
Surgery has been performed, where appropriate, and all 14 women have been receiving follow- up treatment as required. Individual reports about the circumstances in each case will be available to the women by the end of next month.
The late detections were compounded by a shortage of suitably qualified radiologists skilled in assessing the cases of women at risk from breast cancer, the review stated.
The North's health minister, Shaun Woodward, has apologised for the errors and vowed to address the problems.
"On behalf of the health service, I want to apologise for any mistakes that have been made and for the distress caused to those 14 women who had cancers detected," he said. "Individual reports about the circumstances of their case will be made available to all of the women affected by the end of February."
Dr Wilson's report found "clear evidence of substandard care . . . and this has led to significant and avoidable delays in the diagnosis of breast cancer. In a number of these cases it is likely that the care will be determined to be negligent by independent review."
Mr Woodward, while accepting that sub-standard practices had been carried out, said he was pleased the problem had been detected and dealt with promptly. "However, there are lessons that need to be learned from this episode," he said. "I want to ensure that as far as possible, this does not happen again. If we need to change our systems, then we will."
He added: "It is also important that women in Northern Ireland have confidence in the breast cancer screening programme, which has contributed significantly to the reduction in the number of women dying from breast cancer in the last 10 years."
SDLP health spokeswoman Carmel Hanna welcomed the report. "I hope this report goes some way in putting the spotlight back on cancer treatment and care," she said.