A audit of cancer screening in England has found that not one NHS screening programme – including those for bowel, breast or cervical cancer – met their targets last year.
More than 150,000 cervical screening samples have been piled up in laboratories across England waiting to be tested, according to the new report.
A study from the National Audit Office (NAO) found that changes to testing arrangements led to a huge backlog that is still being tackled.
The report also found that, at one point last year, only one in three women undergoing a smear test received their result within the recommended 14 days.
This suggests hundreds of thousands of women have had to wait longer to find out whether they need further tests or treatment.
Some screening programmes are meeting a new "lower threshold" target, which is the minimum number of people the NHS says should be seen.
NAO experts also noted problems with dated IT systems, meaning concerns remain that people may miss out on cancer screening invitations.
It follows serious incidents reported last year regarding the cervical and breast cancer screening programmes, when thousands of women were found to have not been sent invitations.
On cervical screening, the NAO said the roll-out of a programme to first test samples for human papillomavirus (HPV), which is thought to cause most cases of cervical cancer, was announced in 2016, but is not expected to be fully introduced until December 2019.
The move means cervical samples collected from women will be tested for HPV first, to identify those which would benefit from further testing.
As a result, the number of laboratories needed to analyse results will be cut from 48 to nine, meaning staff have been "leaving in search of greater job security".
This has led to a "decline in performance against turnaround time targets" and a build-up of samples waiting to be tested, the NAO said.
Its report said: "In October 2018, there was a backlog of 98,000 cervical screening samples waiting to be tested by laboratories across England.
"NHS England told us that it is working to reduce the backlog, which has been reduced from 152,742 in March 2018 by moving the analysis of samples around the country, to reduce the burden on those laboratories under most pressure."
Some 98% of women should receive their results within 14 days of their cervical screening appointment, but this target has not been met since November 2015, the report went on.
In March 2018, only 33% of women were getting their results on time. By December, this had improved to 55%.
The NAO also said that none of the adult cancer screening programmes met their standard coverage target during 2017-18.
A new lower threshold target has been introduced to reflect the lowest level of performance that programmes are expected to reach.
The report said: "In 2017-18, none of the screening programmes met their standard coverage target although bowel screening achieved coverage of 59.6% against a target of 60%.
"All met their lower threshold except for the cervical screening programme which achieved coverage of 72% against a standard target of 80% and a lower threshold of 75%."
A new bowel scope test for people aged 55 to check for signs of bowel cancer has also not reached as many people as hoped.
By September 2018, 166,043 people had been invited for bowel scope screening, against a target of 499,877 (33%).