Lung Cancer Screening

Screening is the process of looking for cancer before a person develops symptoms. It helps in early detection of cancer. Some types of cancer might be easier to tackle if found at its early stages. Abnormal screening test result mandates further diagnostic evaluations.

Lung cancer is the result of uncontrolled proliferation of cells in lung tissue. This cancer accounts for nearly 1.3 million deaths annually worldwide (as of 2004). Exposure to tobacco smoke is the most common cause of lung cancer. Ideally if a mass cost-effective screening test is available for lung cancer, it could save many lives. However this has not happened so far. Lung cancer screen usually employs two common tests:


Chest x-ray

Sputum cytology

Chest x-ray or chest radiograph is a radiograph of the chest and is used to diagnose conditions affecting the chest, its contents and nearby structures. A chest x-ray is one of the most common investigations ordered in clinical practice.

Sputum cytology

Sputum cytology involves examination of a sample of sputum under a microscope to check for cancer cells.

Unfortunately, it is yet to be proven whether either of these screening tests can decrease the chance of dying from lung cancer.

New tests being studied in clinical trials include:

Spiral or helical CT Scan

In this kind of CT scan, the x-ray machine rotates continuously around the body in a spiral path. It takes cross sectional pictures of the body. It is faster than conventional CT scans, takes clearer deeper 3D pictures and can detect tiny areas of abnormalities that conventional scans may miss. It is the best way to detect an early cancer of the lung but it is extremely expensive and cannot be used for routine mass scale lung cancer screening.

In 2010 the national Lung Cancer Screening trial in USA released its report and has shown that twenty percent fewer lung cancer deaths seen among those who were screened with low-dose spiral CT than with chest X-ray. The National Lung Screening Trial, randomized more than 53,000 current and former heavy smokers ages 55 to 74 and compared the effects of two screening procedures for lung cancer - low-dose helical computed tomography (CT) and standard chest X-ray.