In 2019, 84% of women aged 30 to 49 in high-income countries had been screened for cervical cancer at least once in their lives. In low-income countries, the figure was 11%.
Those numbers come from a 2022 analysis in The Lancet Global Health covering 202 countries and territories, the first global baseline for the WHO’s plan to eliminate cervical cancer. They explain a lot about another number: according to the WHO, around 94% of cervical cancer deaths in 2022 occurred in low- and middle-income countries.
It would be natural to read the screening gap as a shortage of tests. That is the part of the problem that attracts investment, from new devices to cheaper diagnostics to artificial intelligence reading images. But the gap that decides who dies is usually not the test. It is everything that has to happen after it.
Screening is a pathway, not an event
A screening programme only saves lives if a chain of steps holds together. Someone has to be invited, reach the clinic, be tested, get the result, return for follow-up, receive treatment for a pre-cancerous lesion or a confirmed cancer, and be tracked if they miss a step.
Wealthy countries are good at this not because their tests are better, but because the chain is built into the system: population registries, invitation letters, recall reminders, laboratories with capacity and treatment services close by.
In many low-income settings, every link is weaker. There may be no population register to invite from. Results may take weeks, and the woman who travelled a day to reach the clinic may not be able to make the trip again. Treatment for an abnormal result may be available only in a distant city.
Each of those drop-offs erodes the value of the original test. A screening campaign that tests thousands of women but loses most of those with abnormal results before treatment can look impressive in reports while preventing few deaths.
Why “screen and treat” was a bigger idea than any new test
This is why the most important shift in cervical cancer prevention in low-resource settings is not a technology at all. It is the approach WHO recommends of screening and treating in as few visits as possible, ideally one.
The logic is simple. If the most likely point of failure is the return visit, remove the return visit. Test, give the result the same day where possible, and treat pre-cancerous lesions on the spot with ablation methods that don’t require an operating theatre.
HPV testing strengthens this further, particularly when women can collect their own samples. Self-sampling removes the need for a pelvic examination by a trained provider, which is a real barrier where there are few such providers, or where women are reluctant to be examined. It can be done at home or in a community setting.
But self-sampling on its own recreates the same weakness in a new place. A woman who tests positive still needs to be found, told and treated. The test has moved closer to her. The treatment often hasn’t.
The same pattern in rich countries
It would be a mistake to treat this as purely a low-income problem. Inside wealthy countries, screening gaps tend to track income, insurance status, language and geography in the same way.
The mechanism is familiar. Someone with stable work, a regular doctor and flexible hours is more likely to get the invitation, take the time off and return for follow-up. Someone with shift work, no regular doctor or a history of bad experiences with the health system drops out at each step. In any country, it is people with the fewest resources who fall out of the pathway first.
The uncomfortable incentive
Screening programmes are usually measured by coverage: how many people were tested. That metric rewards the first step and ignores the rest.
A programme can raise its coverage figure by running more testing camps while doing nothing about the women lost before treatment. Donors and ministries may reward that, because testing numbers are easy to count and easy to report.
The metric that actually matters is harder to collect: of the people who tested positive, how many were treated, and how quickly? That number reveals where the chain breaks. It is also the one many programmes do not routinely publish.
Where to invest
If the goal is fewer cancer deaths among poorer women, the priorities look different from a device catalogue:
- Shorten the pathway. Every visit removed is a point of failure removed. Same-day results and same-day treatment should be the default where possible.
- Measure treatment completion, not just coverage. Report what share of positive results led to treatment.
- Bring treatment to where tests happen. Portable ablation equipment and trained nurses matter as much as the test kit.
- Invest in tracking. A simple register that follows up positive results often saves more lives than a better test.
- Keep vaccinating. HPV vaccination prevents the disease that screening tries to catch, and it doesn’t depend on a return visit.
A worked example: the leaky pipeline
Consider a hypothetical screening campaign in a rural district, using illustrative numbers to show how losses compound.
A mobile team tests 1,000 women with HPV tests over a month. Suppose 10% test positive: 100 women. Results take three weeks to come back from a regional laboratory. By then, the team has moved on. Community health workers are asked to find the 100 women and tell them to attend the district hospital for follow-up.
Of the 100, perhaps 80 are reached. Of those, 60 make the journey to the hospital. There, some are told the equipment for treatment is broken, or the trained nurse is away, and are asked to come back. Perhaps 40 are ultimately treated.
The campaign report records 1,000 women screened. It may not record that fewer than half of those who needed treatment received it.
Now change the design. The same team uses a test that gives results within hours, and carries a portable device for thermal ablation. Women who test positive and are eligible are offered treatment the same day. Some decline, some need referral for further assessment, but the majority are treated before they go home.
The test was not the main difference. The number of steps was.
These figures are illustrative, not drawn from a specific programme. But the structure is familiar to anyone who has worked in screening: each step loses people, and losses multiply. A programme with five steps, each retaining 85% of participants, keeps fewer than half by the end.
Why the funding flows to the front of the pipeline
There is a reason investment clusters around tests rather than follow-up.
Tests are products. They can be manufactured, procured, priced and counted. A donor can fund a million test kits and report exactly how many were used. A company can build a business around a better test.
Follow-up is a system. It depends on trained staff, working equipment, patient tracking, transport and management. It is harder to procure, harder to count and harder to credit to any single funder. Nobody sells “women who returned for treatment.”
This creates a structural bias. Resources flow to the part of the pathway that is easiest to buy and measure, even when the binding constraint is elsewhere. The result is programmes with impressive screening coverage and disappointing effects on mortality.
The strongest counterargument
The best objection is that better tests genuinely do change the pathway.
HPV testing is more sensitive than older methods, which means fewer screens over a lifetime are needed. Self-sampling can reach women who would never attend a clinic. Point-of-care tests make same-day treatment possible. From this perspective, the technology is not a distraction from the pathway; it is what enables a shorter one.
This is largely right. The most promising approaches combine better tests with a redesigned pathway, and new tests are part of why single-visit screening is now realistic in more places.
The point is not that tests don’t matter. It is that a test’s value depends on the pathway it sits in. The same HPV test that saves lives when paired with same-day treatment can do little if results take weeks and treatment is far away. Buyers should evaluate a test by asking how it changes the number of steps between screening and treatment, not just by its sensitivity.
Second-order effects
Vaccination will shift the screening calculus. As HPV vaccination coverage rises among girls, the prevalence of the highest-risk HPV types will fall in vaccinated cohorts. Over time, screening programmes may be able to screen less often in those groups. Countries that invest in vaccination now are also investing in cheaper screening later.
Overdiagnosis and overtreatment are real in some settings. In wealthy countries, frequent screening can lead to treatment of lesions that would have regressed on their own, with consequences for future pregnancies. As low-income settings adopt screen-and-treat, protocols need to balance the risk of missing disease against the harm of unnecessary treatment.
Other cancers have the same problem. Breast, colorectal and other screening programmes also lose people between an abnormal result and diagnosis or treatment. The cervical example is instructive because the fix, same-day treatment, is unusually feasible. For other cancers, reducing drop-off will require navigation, tracking and faster diagnostic services.
What cervical screening teaches other programmes
The value of the cervical example is that it makes the pathway problem visible in an unusually clean way. Pre-cancerous lesions can be found and treated in one visit, with simple equipment, by trained nurses. When programmes fail, it is rarely because the science is unclear. It is because the steps between test and treatment were never designed as one system.
Other cancers are harder. A suspicious mammogram leads to imaging, biopsy, pathology and surgery, each a potential drop-off point and each dependent on specialists. But the principle carries over: count the steps, measure the losses at each one, and fund the parts of the pathway where people are lost, not just the part where they enter.
What this means for decision-makers
For ministries of health, it means setting targets and reporting on treatment completion, not just screening coverage, and funding the follow-up system alongside the tests.
For donors and procurement agencies, it means evaluating grants and purchases by how they change the number of steps and the time between screening and treatment.
For hospital and district managers, it means making sure the treatment end of the pathway works: equipment maintained, staff trained, and a clear route for women who need more than ablation.
For clinicians and community health workers, it means treating a positive result as the start of a task, not the end of one, and having a simple way to track who has and hasn’t been treated.
What to watch next
Watch whether countries report the share of screen-positive women treated, and whether that number rises as single-visit approaches spread. Watch progress toward the WHO elimination targets for screening and treatment. And watch whether new screening technologies are marketed on how they shorten the pathway, not just on how accurately they detect disease.
The takeaway
The cancer screening gap between rich and poor is real, and it is enormous. But closing it is less about getting more people through the first door than about making sure the first door leads somewhere.
A cheaper test is welcome. A woman who is tested, told and treated on the same day is the thing that saves her life.
In your programmes, what share of positive screening results actually lead to treatment, and do you know? We’d like to hear.
