Almost 5,000 women in Scarborough and Ryedale missed their last screening for breast cancer, NHS figures show.
Women are invited for a breast screening every three years between the ages of 50 and 70, to try to catch cancer early.
But, “troubling” figures show the proportion of women accepting the invitation is declining.
Only 72.6% of the 18,204 women in the Scarborough and Ryedale Clinical Commissioning Group area due a screening in the three years to the end of March took up the offer.
This means 4,992 women are not up to date with their checks.
The data measures how many eligible women were checked at least once in the three year period, meaning some women could be years overdue.
Across England the proportion of women who attended their last check was 72%.
Of those who were sent an invitation in the 12 months to March, just 70.5% had attended within six months of their invite, according to NHS Digital.
This is the lowest level since the current screening programme began in 2007.
The UK National Screening Committee says the minimum acceptable level of coverage is 70%, but the NHS is expected to achieve 80%.
Addie Mitchell, clinical nurse specialist at the charity Breast Cancer Care, said: “Uptake of routine screening invitations in England has been gradually slipping year-on-year.
“These troubling figures show we’re now only a hair’s breadth above the minimum standard.
“While screening is not a one-stop shop, as symptoms can occur at any time, mammograms remain the most effective tool at our disposal for detecting breast cancer at the earliest possible stage.”
Almost a third of the 260 CCGs in England failed to meet the minimum target, while only one managed to pass the 80% benchmark.
In Scarborough and Ryedale, the uptake rate has fallen every year since 2012-13, when it stood at 77.9%.
The breast screening programme uses an X-ray test called a mammogram to detect tumours before they are large enough to feel.
Detecting cancer early on gives a better chance of survival.
Dr Anne Mackie, director of screening at Public Health England, said it was “concerning” that uptake has fallen, particularly among younger women invited for their first test.
She continued: “We are working hard with NHS and local community healthcare colleagues to understand why this might be and to make appointments as easy as possible to attend for all women who want to get screened.”