Patients benefit from early testing
Research, to be presented to the British Thoracic Society's (BTS) winter meeting in London on Thursday, found only 13% of patients knew persistent cough, shortness of breath and chest pain may suggest lung cancer.
It said GPs should refer patients earlier for chest x-rays to confirm diagnosis.
Many people with persistent cough, chest pain and shortness of breath will not have lung cancer, but the BTS said rapid assessment would reassure them.
Many patients are smokers, who do not see a persistent cough as a reason to see their GP.
Lung cancer was recently revealed to be the biggest cancer killer in the UK.
Waiting
The survey of 39 outpatients attending rapid access lung shadow clinics at St George's and Hammersmith Hospitals in London also found over a third - mostly smokers or ex-smokers - who suffered from a persistent cough did not think they needed to see a GP.
On average, they waited 14 weeks before making an appointment, with over half having to be encouraged to seek medical attention.
All had been seen within 2 weeks of referral, but only 42% were referred by GPs, with the remainder coming via hospitals.
Dr Charlotte Rayner, respiratory consultant at St George's Hospital and a member of the BTS, said: "Patients wait before seeking help, either because they are frightened or because they do not realise the seriousness of their symptoms.
"However, in most cases, the sooner a specialist can see a patient the better."
Research from Liverpool presented to the BTS meeting said all GP practices should follow government guidelines introduced in April 2000 which say suspected lung cancer cases should be seen by a specialist within two weeks.
An audit of 117 practices by the Liverpool Lung Cancer Unit, showed by involving GPs in the referral process, we have achieved a high success rate in identifying patients with suspected lung cancer.
Early treatment 'crucial'
Dr John Harvey, of the BTS said: "It is important for all of us to remember that there are effective treatments for many patients with lung cancer and the sooner we can diagnose the better the prognosis for patients."
Dr Maureen Baker, honorary secretary of the Royal College of General Practitioners, told BBC News Online: "What is the evidence that GPs don't pick it up?"
She said she would expect GPs to be alerted to the possibility of lung cancer if a patient presented with the symptoms highlighted by the BTS.
Dr Baker said the speed in diagnosing lung cancer could be improved if test results came back faster to the GP.
"A more streamlined system for having investigations and reports back would be of value," she said.