Most lung cancers that are detected early are found by chest x-rays done
as screening proceedures or by x-rays that are done for investigation of
symptoms not suspected as being due to lung cancer. In my experience,
the most common scenario is that of a patient who develops an upper
respiratory viral cold or flu, and goes to his doctor. When the doctor orders
a CXR, the lung cancer which was not responsible for the symptoms is
found.
CXRs is a good, but flawed method. Small lesions (<1cm.) are
frequently missed even by excellent radiologists. Early lung cancers can be
missed when they arise in hidden areas of the lung i.e. behind the heart or
blood vessels at the root or hilum of the lung.
This link presents a view that I disagree strongly with. This is the orthodox view that is espoused by most organizations in the U.S.
