Background: The primary investigation of lung cancer (LC) is for 85% of the cases conducted through General Practice, sadly it tends to take a relatively long time from first time the patient is seen by their General Practitioner and until they are diagnosed. LC symptoms are common, but usual because of benign diseases. Only 33% of LC patients presenting with alarm symptoms. On average a General Practitioner in Denmark sees only one patient with newly diagnosed lung cancer a year and the doctor will therefore get the clinical experience that when they refer a patient, test often come out negative and they therefore fail to refer and delay will increase - with a poorer prognosis as a result. Centrally in the diagnosis is conventional chest X-ray, which unfortunately is inefficient in many cases, while CT scanning has proven effective even for small tumors.

Hypothesis and aims: The project has three main hypotheses to be tested 1) the GP's use of cancer fast-track and detection of suspected lung cancer can be optimized in relation to interpretation of symptoms and subsequent referral practices and radiological investigation. 2) General Practitioners with special training can change the referral routines and 3) direct access to fast CT scanning leads to earlier diagnosis of lung cancer.

Methods: The first part of the study is a register-based study of lung cancer patients' road to diagnosis, based on a database of newly diagnosed cancer patients in a year. Second part of the study is a clinical, randomized study of the effect of referral directly to fast chest CT scan. Primary endpoint is delay, secondary endpoints are referral pattern (use of fast-track packet), primary use of CT and 1-year mortality. Furthermore side effects, including patient groups with increased delay.

The study will contribute new knowledge to the way GP's interpret symptoms, the way they refer their patients when they suspect cancer, their use of diagnostic imaging and cancer fast-track pathways. It will then provide a unique opportunity to create the necessary knowledge about the effects of direct referral to fast CT scan and it might be a decision aid whether to open for direct CT scan in General Practice for a group of patients.

Inclusion Criteria:

• all practices referring to the Department of Pulmonary Medicine, Aarhus University Hospital.

Exclusion Criteria:

• former lung cancer patients.