Nearly a quarter of all women sent breast cancer screening reminders in Northampton last year did not take up the offer, figures have revealed.
Revelations in recent days that an NHS computer error may have contributed to the avoidable deaths of up to 270 women have led to renewed scrutiny of a national breast screening programme.
The Health Secretary, Jeremy Hunt, admitted last week that the 2009 error meant up to 450,000 women did not receive their invitations.
In 2016-17, 75 per cent of women called for a screening at the Northampton Breast Screening Unit took up the offer. Of those screened, four per cent were referred for further assessment of a potential cancer.
This means Northampton Breast Screening Unit met the national target of 70 per cent.
In a report published in February, the All-Party Parliamentary Group on Breast Cancer found there were unacceptable differences at every level of geography and "between local breast cancer units".
The uptake rate varies significantly across the country, from 80 per cent in North Nottinghamshire to 61 per cent in the West of London unit, prompting concern about the variation in local services.
"These variations are predominantly due to differences in populations and their needs and the way services are organised locally," the report found.
"While such differences remain, this country cannot hope to meet the government's ambition of delivering world-class cancer outcomes for all."
The data also shows the rates of women who were diagnosed with cancer or referred for further treatment after their screening.
Small cancers of less than 15mm were detected in six women out of every 1,000 at their first screening.
Women who had attended more than one screening in the last five years had a small cancer rate of four per 1,000.
In the days since the Health Secretary's announcement, some academics and health professionals have said the statistics may have unnecessarily alarmed women.
Sara Hiom, Director of Information at Cancer Research UK, said: "It is not possible to know for sure how accurate this figure may be, but talking about it in this way, before the findings of the independent inquiry into the error has even started, has served to stir fear.
"Thousands had a choice they should have been afforded taken away from them.
"But breast screening isn't perfect, and the issue is more complex than simple but alarming headlines might lead us to believe."