Doctors are failing to spot early lung cancer symptoms, according to research, meaning that one in three patients die within 90 days of diagnosis.
Respiratory physician Dr Emma O'Dowd who carried out the research at Nottingham University, said family doctors needed more help in recognising patients at a high risk of lung cancer.
The research found that of those who die within three months of discovering the cancer, one in 10 die within a month while one in 20 are not diagnosed until they have died.
Dr O'Dowd said "surprisingly" her research found that those who are given a late diagnosis on average visited their their GP five times in the few months beforehand, countering a common preconception that they would not seek medical attention.
It was therefore "key" to find out what symptoms they were displaying in those consultations, she said, and how they could be better identified by GPs as being linked to lung cancer.
She said: "We're losing a lot of patients early on. I wanted to find out more about these patients who died early and if there are features that can help us to diagnose them earlier.
"I started off with the preconception that people who died early didn't ever see their GP. Actually, they saw their GPs more before diagnosis compared to those patients which lived longer.
"That was a surprising finding but obviously with this piece of work we can see specifically what symptoms they have come in with."
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She added: "Lung cancer can be difficult for doctors to distinguish from other lung diseases so we need to give them some tools that will help identify a patient as high risk.
"If we can diagnose patients at an earlier stage hopefully they can get curable treatment rather than palliative treatment which is what most patients are getting at the moment.
"It's not that we're trying to blame the GPs but if we have tools to identify these high risk people earlier than we should put them to use."
Dr O'Dowd, whose research has been published in the British Medical Journal, added that most GPs are only likely to see one new case of lung cancer a year which is why it is important to promote risk assessment tools.
New software is being developed for doctors that would flag up the risk of lung cancer in patients by tracking their symptoms and lifestyle.
Dr O'Dowd used data from The Health Improvement Network (THIN), which contains the anonymous health records of millions of primary care patients across the UK.
They analysed 20,142 cases of lung cancer recorded by 444 general practices during the study period.
In a linked editorial, Dr Michael Peake, honorary consultant and senior lecturer at the University of Leicester's Glenfield Hospital, agrees that GPs need better tools to support their clinical decision making, so that they can pick up patients at risk earlier on.
He added: "The number of excess deaths linked to deprivation is large and the gap between the least and most deprived has not lessened over time.
"Improved targeting of public awareness campaigns to specific social groups is important so as not to widen this gap further."
The research was funded by the Roy Castle Lung Cancer Foundation, based in Liverpool.
The Royal College of GPs (RCGP) said the early diagnosis of cancer is a priority for family doctors.
Richard Roope, the cancer lead at RCGP, said: "GPs are doing a good job of appropriately referring our patients that we suspect of having cancer and 75% of patients found to have cancer are referred after only one or two GP consultations.
"And it is very encouraging that one-year survival rates for lung cancer are improving.
"Taking into account the global picture, GPs across the UK are doing very well considering the meagre resources available to us; funding for general practice is at an all time low, we have a chronic shortage of doctors, and access to CT scanners, that would help in the diagnosis of lung cancer, is very limited in UK primary care."
He added that significant, ongoing public awareness campaigns to educate the public about the causes and symptoms of lung cancer are also required.