In the United Kingdom, women between the ages of 50 and 70 are entitled to a breast cancer screening every three years, as part of the government-run universal health-care system. Women registered with a primary-care physician get automatic reminders inviting them to come in.

But this week, Health Secretary Jeremy Hunt revealed that the system had broken down. At least 450,000 women between the ages of 68 and 71 had not received their notices since 2009. Thousands did not come in for screenings as a result. And Hunt says hundreds may have died because of the oversight.

“It is incredibly upsetting to know that you did not receive an invitation for screening at the correct time and totally devastating to hear you may have lost or be about to lose a loved one because of administrative incompetence,” Hunt said.

In his speech to the House of Commons, Hunt apologized “wholeheartedly,” acknowledging that the screening program had “not been nearly good enough.”

The problem stretches back to 2009. It was caught because of an upgrade to the IT system of the breast cancer screening invitation program. Because of a glitch in the algorithm, many women around the age of 70 did not get an invitation for their final screening. Women stop receiving letters after that screening.

Hunt told lawmakers that all of the women who should have received a screening will get a letter by the end of May, urging them to come in for an appointment. He also promised that not one of them would have to wait more than six months for an exam. According to Hunt, 309,000 of the affected women are still alive. A computer model suggests between 135 and 270 women may have had their lives shortened as a result, he said.

Cancer organizations expressed frustration and outrage. Breast Cancer Now CEO Delyth Morgan told the Guardian it was “beyond belief” that the issue continued for a decade. It's a “colossal system failure,” she said.