The goal of a screening program is to find cancer at an early stage when there are fewer symptoms. Treatment at early stages of cancer can lead to more treatment options, less invasive surgery, and a higher survival rate. For example, in recent years, the five-year survival rate of persons whose cancers were diagnosed when they were still localized (had not spread) was almost 50%. This drops to 2% for persons whose cancers were diagnosed after their cancers had spread distantly. Even though early detection can save lives, there is currently no approved screening test for lung cancer that has been proven to improve survival or detect localized disease. There are studies underway, though, to find appropriate screening tools.
Early detection of lung cancer is critical for improving survival of this disease because only 15% of lung cancers are found when they are localized. Since there are few or no symptoms in the early stages of the disease, the majority of lung cancers are diagnosed in the late stages of the disease. Symptoms of later-stage disease may include a persistent cough, sputum streaked with blood, chest pain, voice change, and recurrent pneumonia or bronchitis.
Testing people who are known to be at high risk for developing lung cancer may help find tumors at an earlier stage when they are small and more easily treated. People at high risk include men and women
Possible screening techniques for lung cancer include
Efforts are underway to find effective ways to screen for lung cancer. The National Lung Screening Trial is a clinical trial to assess whether screening individuals at high risk for lung cancer with spiral computerized tomography (CT) or standard chest x-ray can reduce lung cancer deaths. Even though this clinical trial is fully enrolled and is not accepting any new patients, any person who is at increased risk of developing lung cancer should consult their doctor to discuss screening with a low-dose helical CT scan even though this screening is somewhat controversial.
Although spiral CT scans can detect tumors in the earliest stages of disease, there is debate among the medical community about whether this earlier detection ultimately saves lives. Some experts are concerned that screening will lead to over diagnosis, or the detection of cancers that would not have caused symptoms prior to the patient dying of other causes. Additionally, the procedures, such as needle biopsies, that are required to investigate irregularities on the scans can be quite invasive and have their own risks, such as collapsing a lung. False positives (the test shows something on the patient’s lung even though it may not be cancer) can be common because the test can mistake scar tissue or a benign lump for cancer. Other medical experts feel the benefits of early detection of lung cancer outweigh the uncertainty of false positives.