More than 150,000 cervical screening samples have been piled up in laboratories across England waiting to be tested, according to a 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.
In March last year, 152,742 samples were waiting to be checked. By October, the figure was 98,000.
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.
The NAO study found that not one NHS screening programme – including those for breast and bowel cancer – was meeting national targets for how many people should be screened.
Some 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 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 none of the adult cancer screening programmes met their standard coverage target during 2017-18, although bowel screening achieved coverage of 59.6% against a target of 60%.
It added: “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%).
There is also variation across the country in how many people get screened across all programmes.
The NAO warned of poor IT infrastructure for the screening programmes.
It said: “All the screening programmes rely on a complex and ageing IT system to identify who to invite for screening.”
A legacy database of GP registrations has been described by the Department of Health and Social Care as “not fit for purpose for screening programmes”.
NHS England had intended to replace this in 2017 but this has now been delayed, causing “additional cost and greater risk that screening services cannot reliably identify and invite eligible populations for screening”.
Labour MP Meg Hillier, chairwoman of the Commons Public Accounts Committee, said it was “worrying that not everyone who is eligible to take part in screening programmes is doing so.”
She added: “Those responsible for screening programmes are not always capable of picking up when people are not invited for a screening appointment, or ensuring that people receive their test results on time.”
Dr Fran Woodard, executive director of policy and impact at Macmillan Cancer Support, said: “It’s deeply concerning that the number of people receiving screening for cancer and prompts for results is so inconsistent across different parts of England.
“We must take action to ensure that earlier diagnosis for all is not an aspiration but a reality and that as a minimum, services are operating to the ‘agreed standards’ for screening, regardless of where you live.”
Robert Music, chief executive of Jo’s Cervical Cancer Trust, said: “Over the past year we have had many women contacting us with concerns over delays in their results and it is simply not fair that women should be put under undue stress as a result of failings in the programme management.”
A Department of Health and Social Care spokesman said: “Prevention and early diagnosis of cancer are key priorities for this Government, and we are already working closely with NHS England and Public Health England to address the issues this useful report highlights.
“An independent review announced by NHS England is looking at cancer screening services. We expect this to lead to an overhaul of the system so it meets the high standard NHS patients rightly expect.”