Almost all women are waiting longer than two weeks to get their smear test results.
Patients from this area are experiencing longer than the mandatory 14-day turnaround - which was introduced in 2010.
A Freedom of Information request to Public Health England has revealed 96% of those screened in the NHS Dartford, Gravesham and Swanley Clinical Commissioning Group area in the 12 months to July waited longer than two weeks for their results.
This means 12,140 women who attended a smear test in this period didn’t get their results through on time.
More than three million results were sent out in England over the same period, and almost half of them were late.
Leading cancer charities have described the figures as “concerning”, adding that long waits could cause increased anxiety at an already stressful time.
Only 16 out of 195 CCGs met the threshold for providing 98% of results within two weeks and one CCG - East Staffordshire - failed to get any results out on time.
Robert Music, chief executive of cervical cancer charity Jo’s Trust, said: “Lots of people have approached us through our helpline saying they are waiting 12, 14, 16 weeks for their results.
“It is creating anxiety which is not a healthy thing, and our concern is that it could put women off attending their appointments.
“With screening attendance already at a 20-year low, that is worrying.”
He added that it was believed survival rates for women who do develop cervical cancer would be unaffected by the increased waits, but that this couldn’t be certain in every single case.
Impending changes to the way cervical screenings are carried out are being blamed for the backlog of test results across the country.
A new test which will look for the cancer-causing HPV virus straight away rather than for abnormal cells in the cervix will be rolled out across the whole of England in 2019.
According to Mr Music, fewer cytologists - the scientists who study the test samples - will be needed with the new method, and this has caused shortages of staff as they leave for new jobs ahead of the change.
Cancer Research UK said it understood the challenge the NHS was facing ahead of the HPV switch, but said it was important for turnaround times to be reduced “as quickly as possible”.
An NHS England spokesman said: “NHS England and Public Health England are committed to the introduction of primary HPV screening, which will identify more women at risk and save more lives.”