Lung Cancer Screening

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.

Frequently Asked Questions

1) Which specialist doctor can perform screening for lung cancer?

A chest physician or even a general physician can advice perform this screening

2) Do screening tests carry risks?

Yes.

False negatives: Sometimes screening tests may give false negative results, i.e. tests may show that there is no cancer even when there really is. This delays seeking medical care even if the patient has symptoms.

False positives: Sometimes tests show that there is cancer even if the person doesn’t have one. This results in undue anxiety and may lead to unnecessary interventions.

Radiation exposure from chest x-rays may increase the risk of developing breast cancer.

3) When should I get a lung cancer screening?

There is no standard protocol with respect to screening for lung cancer. Screening is usually done before a person develops any symptoms.