There was a fourfold increase in the diagnosis of potentially curable cancers in the Manchester pilot, Macmillan Cancer Support said.
Early diagnosis of lung cancer in "stages one or two" is seen as crucial for a patient's survival.
Consultant Dr Phil Barber said: "We believe we have saved lives."
Dr Barber, from University Hospital South Manchester NHS Trust (UHSM), said: "If we hadn't picked them up [the patients] with this targeted method they might have come to us either one year or two years later and they would have been incurable."
More than 2,500 people with a history of smoking took part in the month-long Manchester Lung Health Checks which saw CT scanners set up in shopping centre car parks from June 2016.
Smokers and ex-smokers aged between 55 and 74 in three deprived areas - Harpurhey, Gorton and Wythenshawe - were offered a free health check followed by an on-the-spot scan.
Data provided by UHSM found that:
Thousands of lives across the UK could be saved after a scheme in which smokers received CT scans in shopping centres, a cancer charity says.