What Procedures Are Involved in Diagnosing Lung Cancer

When your doctor suspects lung cancer, the process usually starts long before any biopsy or major procedure. You’ll answer detailed questions, undergo a focused exam, and likely have imaging tests like chest X‑rays and CT scans. From there, things can become more complex, involving scopes, needles, and sometimes surgery. Understanding what each step is for can help you feel more in control, especially when you know what may come next…

When Doctors Suspect Lung Cancer

Doctors typically begin to suspect lung cancer when symptoms or imaging findings don't fit a straightforward cause, such as a simple infection, and instead suggest a more serious underlying problem. In this situation, they follow a structured evaluation process.

First, your doctor will take a detailed medical history, including smoking and occupational exposures, review your symptoms, and perform a physical examination. They usually order imaging studies such as a chest X‑ray and often a chest CT scan to look for lung nodules, masses, or other abnormalities.

If these findings raise concern for cancer, the next step is to obtain tissue or fluid samples to confirm the diagnosis. Depending on where the abnormality is located, this may involve:

• Bronchoscopy, in which a thin tube with a camera is passed into the airways to visualize and biopsy suspicious areas.
• CT‑guided needle biopsy, where a radiologist uses CT imaging to guide a needle through the chest wall into a lung nodule or mass.
• Thoracentesis, if there's fluid around the lung (pleural effusion), to remove and analyze this fluid.

To assess lymph nodes in the chest, doctors may use:

• Endobronchial or endoscopic ultrasound (EBUS/EUS) to guide needle biopsies of lymph nodes.
• Mediastinoscopy, a surgical procedure to sample lymph nodes in the central chest.
• Video‑assisted thoracoscopic surgery (VATS) or, less commonly now, open surgery to obtain larger tissue samples or to access hard‑to‑reach areas.

As thoracic specialists such as Marco Scarci often emphasize, choosing the right diagnostic procedure depends not only on the location of the abnormality but also on balancing accuracy with the least invasive approach possible. Learn more about the lung cancer diagnosis and treatment options he offers here:

https://marcoscarci.co.uk/lung-cancer-surgery-guide-diagnosis-treatment/

Pathologists examine these samples under a microscope and often perform additional molecular or genetic tests. The results help determine the type of lung cancer, its stage (how far it has spread), and which treatments, such as surgery, radiation, chemotherapy, targeted therapy, or immunotherapy, are most appropriate.

Imaging Tests Used to Diagnose Lung Cancer

When lung cancer is suspected, imaging tests are a key part of evaluating the lungs and surrounding structures. The process often begins with a chest X-ray, which can show obvious masses, areas of collapse, or fluid, but may miss small or early-stage cancers.

Low-dose CT (LDCT) provides more detailed cross-sectional images than X-ray and is the preferred screening method for people at high risk, such as long-term smokers. It can detect small lung nodules that aren't visible on standard X-rays. When an abnormality is found, a contrast-enhanced CT scan is often used to better define the nodule’s size, shape, density, and precise location, and to assess nearby lymph nodes and other structures.

Positron emission tomography combined with CT (PET/CT) uses a radioactive tracer to identify areas of increased metabolic activity, which can help distinguish between likely malignant and benign lesions and evaluate whether cancer has spread to lymph nodes or distant organs.

Magnetic resonance imaging (MRI) is typically used when there's concern about spread to the brain, spine, or certain soft tissues, while bone scans or PET/CT are employed to investigate possible bone metastases. Together, these imaging tests help determine the extent of disease and guide decisions about biopsy and treatment.

Biopsy Procedures for Lung Cancer Diagnosis

Imaging studies can suggest the presence of lung cancer, but a biopsy is required to confirm the diagnosis and to obtain information needed for treatment planning, including tumor type and molecular characteristics.

In transthoracic needle biopsy, a radiologist uses CT or fluoroscopic guidance to advance a needle through the chest wall into a lung lesion, typically one located in the outer (peripheral) lung. This approach usually yields core tissue adequate for histologic evaluation and molecular testing, such as analysis of EGFR, ALK, KRAS, and PD-L1 status. The main complication is pneumothorax (air in the pleural space), which may require observation alone or, in some cases, placement of a chest tube.

Bronchoscopic biopsy involves passing a flexible bronchoscope through the mouth or nose into the airways to sample centrally located tumors or adjacent lymph nodes. Techniques such as endobronchial ultrasound–guided transbronchial needle aspiration (EBUS-TBNA) allow targeted sampling of mediastinal and hilar lymph nodes for staging and diagnosis.

Surgical biopsies, including video-assisted thoracoscopic surgery (VATS) or open thoracotomy, are used when less invasive methods are inconclusive or inadequate. These procedures can provide larger tissue samples, which are useful for detailed histologic assessment and extended molecular profiling.

Pleural procedures, such as thoracentesis or pleural biopsy, are performed when there's a pleural effusion or suspected pleural involvement, allowing evaluation of malignant cells in pleural fluid or tissue.

How Lung Cancer Is Staged (Has It Spread?)

Although identifying a lung tumor is important, staging determines how far the cancer has spread and which treatments are appropriate. The care team typically uses imaging tests, such as CT, PET/CT, and often brain or spine MRI, along with targeted tissue sampling to assess this.

For non–small cell lung cancer, staging follows the TNM system:

• T describes the size of the primary tumor and whether it has grown into nearby structures.
• N indicates whether cancer has spread to nearby (regional) lymph nodes.
• M shows whether there are distant metastases (spread to organs such as the liver, bones, brain, or adrenal glands).

These factors are combined to classify the cancer from stage I (earliest) to stage IV (most advanced). PET/CT can help identify areas of active cancer in lymph nodes or distant organs. If lymph nodes in the chest appear abnormal on imaging, procedures such as EBUS-TBNA (endobronchial ultrasound–guided needle aspiration), EUS (endoscopic ultrasound), or mediastinoscopy may be used to obtain tissue samples and confirm whether cancer is present.

Small cell lung cancer is usually staged more simply as either “limited stage” (confined to one side of the chest and within a single radiation field) or “extensive stage” (spread beyond that area).

Understanding Your Results and Choosing a Treatment Plan

Staging describes how far the lung cancer has spread. The next step is to understand how your test results inform your treatment options.

The pathology report identifies the specific type of lung cancer and whether it's invasive. This information helps determine whether local treatments such as surgery are appropriate, or whether systemic therapies (such as chemotherapy, targeted therapy, or immunotherapy) are more suitable. Imaging studies and lymph node evaluations define the cancer stage and help guide choices among treatments such as surgery with curative intent, stereotactic body radiotherapy (SBRT), combined chemotherapy and radiation (chemoradiation), or treatment focused on symptom control (palliative care).

Molecular and biomarker testing, particularly in non–small cell lung cancer, can identify genetic changes or protein markers that may be treated with targeted therapies or immunotherapies.

Pulmonary function tests evaluate how well your lungs work and help determine whether you can safely have part of a lung removed or whether non-surgical options such as SBRT may be safer.

You and your care team use these results in a shared decision‑making process, weighing the potential benefits, risks, and impact on quality of life to select a treatment plan.

Conclusion

By now, you know the key steps doctors use to diagnose lung cancer, such as history and exam, imaging, biopsies, staging tests, and lab analysis. You’re not just “waiting for results”; you’re taking part in a structured process that leads to clear answers. Use this knowledge to ask questions, understand each recommendation, and weigh your options. With your team, you can choose a treatment plan that fits your cancer stage, health, and personal goals.