The strategy for diagnosing lung cancer depends on the size of the tumor, localization in the lung, whether there are obvious metastases and the patient's clinical condition at the time of the diagnosis. Stage determination of the tumor usually occurs in parallel because the most concise approach depends on the stage of the disease.
Diagnostic work-up is based on few examinations with high diagnostic precision.
The medical history should emphasize the patient's smoking habits/patterns and if there have been any work-related exposures for considering potential compensation claims.
The term "pack years" refers to 20 cigarettes in a packet and it is calculated by how many packets have been smoked. The formula is the number of daily cigarettes/20 x the number of smoking years. Forty cigarettes per day for 5 years is equivalent to 10 pack-years (40/20 x 5 years), while 10 a day for 40 years is equivalent to 20 pack-years.
The performance level (WHO) should always be noted as well as any weight change.
The clinical examinations should be focused on:
- lymph nodes on the neck, supraclavicular, axillar, and inguinal
EKG and spirometry are performed. If necessary, an extended physiological respiration work-up is performed including diffusion capacity (DLCO), walking test, and cycling test.
Blood tests are rarely of diagnostic value, but may be useful in diagnosing paraneoplastic phenomena which occur in about 10% of patients.
- CT scan of thorax and upper abdomen
MRI or CT scan of the head should be carried out when there are abnormal symptoms or sign from the nervous system. PET-CT should be performed in all cases considered for curative treatment.
Bronchoscopy with biopsy
If there is suspicion of a centrally located tumor on a CT or clinical sign of lung cancer, bronchoscopy is decisive for verification of the cancer diagnosis. The diagnosis can be made either by biopsy, or by cytological examination of fine needle aspirate or brush specimens.
Although bronchoscopy is primarily a diagnostic test for lung cancer, the examination may also provide information of disease (T and N classification).
Esophageal and endobronchial ultrasound
Esophageal (EUS) and endobronchial (EBUS) ultrasound are performed when there are enlarged lymph nodes and/or tumors in the mediastinum causing suspicion of infiltration of malignant cells. This examination method has to some extent replaced mediastinoscopy.
Transthoracic percutaneous needle biopsy and fine-needle aspiration
A percutaneous needle biopsy and fine-needle aspiration cytology (FNAC) can be carried out by means of fluoroscopy or guided by CT or by ultrasound if the tumor is close to the pleura.
Mediastinoscopy / anterior mediastinotomy
For the histological diagnosis of enlarged nodes in the mediastinum shown by CT, which are not available by EUS or EBUS, a mediastinoscopy should be performed. The procedure can also be performed even if the enlarged lymph nodes themselves are not available for mediastinoscopy, because tumor infiltration can be found in normal-size glands of these patients.
If enlarged lymph nodes are localized at level 5 (subaortal) and 8 (phrenic), a left anterior mediastinotomy may be performed.
Detection of malignant cells in pleural fluid is of diagnostic value for M1a tumors. In patients with suspicion of lung cancer and pleural exudate, evacuation of the fluid should occur for cytological diagnosis.
Thoracoscopy with biopsy can also be carried out if there is suspicion of malignancy in a patient who has a solitary nodule and stage I illness based on CT scan of the chest.