Lung Cancer Early Detection & Diagnosis

Lung cancer diagnosis

Having symptoms such as cough and chest pain does not necessarily mean that you have lung cancer. These symptoms should not be neglected, but the right path to take is visiting your doctor and going through exams to figure out what is going on. Lung cancer is a possibility, but it is often the least likely.

To diagnose your problem and detect lung cancer, doctors can take different ways depending on your initial symptoms. There is also screening for lung cancer that is performed in apparently healthy individuals.

In this article, we’re briefly reviewing the most important tests and procedures doctors use to diagnose lung cancer. We’re also covering the updated recommendations for screening lung cancer in high-risk individuals.

Imaging Techniques

Imaging techniques

In most cases, lung cancer will be visible through different imaging tests, including an X-ray or a CT scan. Each one is used differently and at various stages of the diagnosis.

  • Chest X-rays: It is a standard procedure for respiratory conditions because it pictures the lungs and the airways very clearly. It is also the first imaging test performed in patients with this type of symptoms. In chest X-rays, lung cancer shows up as a mass or a conglomerate of masses. In some cases, patients have abnormalities in the chest’s medial structures, called mediastinum, or they can have an enlarged hilum (the section of the airways that connects to the lungs). Patients with somewhat advanced disease may have pleural effusion and thickening of the pleura. This initial finding is often confirmed with other imaging techniques, especially a CT scan.
  • CT scan: It is the second step and provides a more accurate image of the anatomic properties of the mass. It is often combined with PET scans in high-risk patients to offer a more precise understanding of cancer and its staging. Combined with PET, a CT scan can be helpful to differentiate between cancer and inflammatory conditions of the lungs. They also contribute to direct a needle biopsy and detect local and distant metastasis.

Sputum and Pleural Fluid Cytology

Sputum and pleural fluid cytology

In patients with chronic cough and sputum, a sample can be taken to the laboratory to evaluate what is happening and what type of tissue can be found. Sputum cytology contributes to the diagnosis because some patients with lung cancer cough up particles of the primary tumor or cancer cells that will be visible under the microscope.

Another possibility is taking a sample of the pleural fluid if there is pleural effusion. Malignant cells can be found in this liquid, too. In these cases, pleural effusion is by itself a sign of poor prognosis and is usually associated with advanced lung cancer.

Sputum cytology is not always reliable, and there are many false-negative results. Thus, it is a good idea to obtain a large sample of pleural fluid or sputum to increase the likelihood of detecting cancer cells. The sample also needs to be processed immediately because if the patient takes too much time in taking the sample to the laboratory, cells tend to break down and yield a false-negative result.

Diagnostic Procedures

Diagnostic procedures

Diagnostic procedures are more invasive than cytology and often require specialized equipment. However, they provide the most accurate description of cancer and the most reliable diagnosis. They include:

  • Percutaneous biopsy: This procedure is commonly used in patients with suspected metastasis in the liver, adrenal glands, lymph nodes, or pleura. It is performed with a needle puncture guided by imaging techniques such as CT scan or ultrasound. It is the least invasive procedure on this list, and it is usually risky in patients with emphysema.
  • Bronchoscopy: This is the most common diagnostic procedure to obtain a direct sample of the lung tumor. This exam is fundamental to stage lung cancer, and it is much more accurate than other diagnostic techniques. In this exam, a bronchoscope is used and goes through your mouth or nose to reach the airways and directly see what is happening there. The doctor may also take a sample of the tumor to perform a biopsy.
  • Mediastinoscopy: This procedure is helpful in patients with suspicious mediastinal lymph nodes. It is an alternative to endobronchial ultrasound-guided biopsies, usually performed as a part of a bronchoscopy.
  • Open lung biopsy: This type of biopsy is done as a part of a complex surgical procedure known as open thoracotomy. It is the most invasive technique and only performed if no other method is available to diagnose lung cancer.

Screening For Lung Cancer

Screening for lung cancer

An early diagnose of lung cancer provides a better chance of survival without complications. But most types of cancer only give out signs and symptoms when it is already too late. That’s why screening for lung cancer is essential for people with a high risk. This allows doctors to detect patients with early disease, treat them with surgical resection of the tumor, and reduce the therapy’s aggressiveness.

The usual screening method is an X-ray, but recent studies show that using a CT scan reduces the number of cancer death further. In any case, screening should be done in active smokers of 30 packs a year or more, former smokers who had quit smoking within 15 years, especially if they are 55 to 80 years.

Certain tumor markers are being studied to screen lung cancer using molecular analysis. Genes such as p53, EGFR, and K-ras are likely going to become future markers of the disease.

After detecting cancer, different methods can be used to stage the disease and guide our future directions. In this stage, it is crucial to ask all of your questions to the doctor and take your time to decide what to do and which treatment strategies to follow. Lung cancer is not an easy diagnosis to process, and you may need help to cope with symptoms or your own emotions. Talk openly to your doctor about it and discuss the pros and cons to make an educated decision.

References:

National Lung Screening Trial Research Team. (2011). Aberle DR, Adams AM, Berg CD, Black WC, Clapp JD, Fagerstrom RM, Gareen IF, Gatsonis C, Marcus PM and Sicks JD: Reduced lung-cancer mortality with low-dose computed tomographic screening. N Engl J Med365, 395-409.

Wender, R., Fontham, E. T., Barrera Jr, E., Colditz, G. A., Church, T. R., Ettinger, D. S., … & Smith, R. A. (2013). American Cancer Society lung cancer screening guidelines. CA: a cancer journal for clinicians63(2), 106-117.

Rivera, M. P., & Mehta, A. C. (2007). Initial diagnosis of lung cancer: ACCP evidence-based clinical practice guidelines. Chest132(3), 131S-148S.

Rivera, M. P., Detterbeck, F., & Mehta, A. C. (2003). Diagnosis of lung cancer: the guidelines. Chest123(1), 129S-136S.