In just one year, around 115,000 cancer patients in England are diagnosed too late to give them the best chance of survival, according to new calculations from Cancer Research UK.
This means that nearly half of all cancers diagnosed with a known stage in England are diagnosed at stage 3 or 4.
And of these, around 67,000 people are diagnosed at stage 4 - the most advanced stage - leaving them with fewer treatment options and less chance of surviving their disease.
There are lots of things that can influence how early or late someone is diagnosed, but workforce shortages are a large contributor.
There is a desperate shortage of NHS medical staff trained to carry out tests that diagnose cancer, meaning that efforts by the health system to diagnose and treat cancer more swiftly are being thwarted.
Last year, the Government made an important pledge to improve the number of people diagnosed with early stage cancer - a jump from two in four diagnosed early to three in four by 2028 which could save thousands of lives.
Cancer Research UK has calculated that to reach this target, an extra 100,000 patients must be diagnosed early each year by 2028.
NHS staff are working tirelessly to offer the best care possible, and the NHS is implementing important new initiatives to address late diagnosis and improve staff efficiency.
But there just aren't enough of the right staff available on the ground now, and there are no plans to significantly increase the numbers needed to transform the health service.
An earlier diagnosis can be the difference between life and death.
If bowel cancer is diagnosed at the earliest stage, more than nine in 10 people will survive, but if it is diagnosed at the latest stage, just one in 10 people will survive their disease for at least five years.
Efforts to diagnose more patients at an early stage means more people being referred urgently for tests, a vital shift for prompt diagnosis and treatment.
But increasing referrals have left diagnostic staff under great pressure because of vacant posts, a lack of funding to train new doctors and growing lists of patients.
At least one in 10 of these posts is empty, so the Government needs to urgently invest in the cancer workforce if they plan to save more lives now, and in the future.
Without the staff, the Government will not achieve its own ambition.
Emma Greenwood, Cancer Research UK's director of policy, said: "It's unacceptable that so many people are diagnosed late. Although survival has improved, it's not happening fast enough. More referrals to hospital means we urgently need more staff. The Government's inaction on staff shortages is crippling the NHS, failing cancer patients and the doctors and nurses who are working tirelessly to diagnose and treat them.
"By 2035, one person every minute will be diagnosed with cancer but there's no plan to increase the number of NHS staff to cope with demand now or the growing numbers in the future. Saving lives from cancer needs to be top of the agenda for the new Government and it must commit to investing in vital NHS staff now to ensure no one dies from cancer unnecessarily," added Greenwood.
An underpowered workforce is not the sole reason for late diagnoses.
Other factors include symptoms being hard to spot, GPs having too little time to investigate people thoroughly, low uptake of screening programmes or the cancer being advanced when detected.
But right now, staff shortages are affecting every part of the pathway.
According to work commissioned by Cancer Research UK, it is estimated that by 2027, the NHS needs:
By 2035, more than 500,000 people will be diagnosed with cancer in the UK, compared with nearly 360,000 today.
With an ageing population, more tests will need to be carried out to diagnose more cancers and diagnose them earlier.
Dr Giles Maskell, Cancer Research UK's radiology expert, said: "We can feel the bottleneck tightening in the NHS - the pressure is mounting on diagnostic staff. We don't have nearly enough radiologists in the UK right now and far too many patients are waiting too long for scans and results.
"NHS staff are working as hard as they can, but we won't be able to care for the rising number of cancer patients unless the resources are found to train more specialist staff. Extra scanners are welcome, but they will achieve nothing without staff to run them and experts to interpret the scans. It's like buying a fleet of planes with no pilots to fly them," explained Dr Maskell.
Source: Cancer Research UK