Symptoms of Lung Cancer
One of the first steps in diagnosing lung cancer is looking for possible symptoms. Some common symptoms of lung cancer include a cough that doesn't go away or gets worse, coughing up blood or rust-colored sputum, chest pains, recurring pneumonia or bronchitis, hoarseness, loss of appetite, and unexplained weight loss. While not everyone with lung cancer will experience symptoms in the early stages, becoming aware of changes in your body is important for early detection.

Diagnostic Imaging Tests

If a patient experiences concerning lung cancer symptoms or is considered at high risk, their doctor will likely order imaging tests to examine the lungs more closely. Common types of imaging tests used for lung cancer screening and diagnosis include:

- Chest X-ray - A basic X-ray can reveal abnormal growths in the lungs but is less sensitive than other options.

- CT (Computerized Tomography) Scan - A low-dose CT scan uses X-rays and computer analysis to create cross-sectional Lung Cancer Diagnostic And Screening images of the chest. It is more detailed than a regular chest X-ray and can detect small nodules or masses.

- MRI (Magnetic Resonance Imaging) Scan - Used less commonly than CT scans for lung cancer, MRI uses magnetic fields and radio waves rather than radiation. It produces very detailed images and is especially useful when evaluating how far cancer may have spread in the body.

- PET (Positron Emission Tomography) Scan - A PET scan usually follows a CT or MRI scan. It involves injecting a small amount of radioactive substance and using a scanner to detect where it accumulates in the body. Areas of cancer tend to appear brighter on the images since they use more glucose.

Tissue/Fluid Testing

If imaging shows potential lung abnormalities, the next step is usually obtaining a tissue or fluid sample for analysis. Common procedures include:

- Bronchoscopy - A thin, lighted tube (bronchoscope) is inserted through the mouth or nose to examine the inside of the lungs directly. Small samples of visible growths can be collected.

- CT-guided needle biopsy - With CT image guidance, a thin needle is inserted through the skin and into a lung mass. A tiny piece of the mass is removed for examination.

- Thoracentesis - Inserting a needle into the chest cavity to withdraw and examine fluid that has accumulated. Sometimes tumor cells can be discovered in pleural fluid.

- Mediastinoscopy - Making a small incision above the breastbone to access lymph nodes between the lungs for sampling. Enlarged nodes may indicate spread.

- Thoracotomy - A surgical procedure where an incision is made between the ribs to access the inside of the chest cavity for extensive sampling and examination.

Pathology Review and Staging

All tissue, fluid, and cell samples are sent to a pathologist who examines them under a microscope. The pathologist determines if cancer is present and if so, what type based on how the cells look. The results help establish a diagnosis of lung cancer versus other possible disease.

If cancer is confirmed, additional testing is done to determine how far it has spread, known as the stage. Staging helps determine prognosis and the most appropriate treatment. It involves considering results from imaging tests, biopsy samples, and sometimes surgical exploration of lymph nodes and other areas. Together these diagnostic steps work to provide a clear picture of whether cancer is present and if so, how aggressively it has developed.

Molecular Testing

As knowledge of lung cancer at the molecular level has advanced, additional specialized tests may be used following diagnosis. These molecular tests examine the genetic changes and mutations driving a patient's specific cancer. Examples include testing for EGFR, ALK, ROS1, BRAF, and PD-L1 protein expression levels. Results can help doctors choose targeted therapy drugs designed to attack the unique changes fueling tumor growth. Molecular profiling is becoming increasingly important for selecting optimal personalized treatment options.

Screening Options for Early Detection

Screening refers to testing high-risk individuals for cancer even before symptoms appear, allowing for potentially earlier intervention. The main screening option for lung cancer is annual low-dose CT scans for adults aged 50-80 with a 20 pack-year smoking history who currently smoke or quit within the past 15 years. Studies show CT screening can reduce lung cancer deaths. However, it also comes with risks of false positives and overdiagnosis requiring further testing, so people should discuss the pros and cons with their doctor. Biomarker blood tests and chest X-rays are not recommended for lung cancer screening due to inferior accuracy versus CT. Overall, screening combined with preventive measures holds promise for improving lung cancer outcomes.

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