Low-dose CT Scans May be Solution for Lung Cancer Screening
Written by Stephen Sevigny, MD
Lung cancer is the third most common cancer among men and women and is the leading cause of cancer-related deaths. It currently accounts for nearly 27 percent of cancer deaths in total. Current estimates suggest that almost 7 percent of persons born today will be diagnosed with lung cancer in their lifetimes.
Seventy-five percent of patients with lung cancer present with symptoms due to incurable advanced local or metastatic disease. Such a common disease, which presents so late with such significant mortality, should leave itself amendable to a successful screening exam to allow for early detection, and hopefully, treatment.
Medicine has been in search of a lung cancer screening test for decades. Numerous studies had previously concentrated their efforts on chest radiographs, or chest X-rays (CXR), as they are commonly known. Unfortunately CXR’s proved to be too insensitive for lung cancer detection. Although successful in finding many cancers, the cancers found were often too advanced to change the patient’s prognosis and outcomes. Recently a new study, a low radiation dose CT scan of the lungs, has proven very successful in finding cancers early enough to allow for treatment and cure.
With any disease, prevention is the best cure. Eighty-five percent of lung cancers in the US are directly related to smoking and the risk continues even after the person stops smoking. Although the government has done its best job to educate the public to the harms of smoking, current estimates are that 20 percent of American adults still smoke.
In 2013, the US Preventative Task Force (USPTF) came out with a recommendation of low dose CT scans for the early detection of lung cancer. Numerous studies were accumulated and evaluated for patient benefit. Patients who received low dose screening CT scans showed a 20 percent decrease in lung cancer mortality. Based on collected study data, the USPTF suggested that low dose CT screening begin at age 55 and continue until age 80. Screening should be limited to patients who have a 30 pack-year smoking history and currently smoke, or patients who have smoked in the past 15 years. To calculate your pack-years, multiply the number of packs smoked per day times the number of years smoked. For example, 1.5 packs a day for 20 years would equal 30 pack-years.
Low dose CT scans can only be ordered by your doctor. Medicare and many insurance companies will now cover the costs of a low dose CT scan. For the patient to qualify, the patient needs to be asymptomatic, i.e. no symptoms of cancer; be between 55-77 years of age; and have the minimum of 30 pack-years. The scan requires no contrast typically found with many CT scans. The patient simply lies on a table and gets scanned during a 4-6 second breath hold. The study will then be read by a board-certified radiologist and results given to the patient’s doctor.
Tiny nodules may need to be followed up with a follow-up scan in six months.
In addition to lung cancer, the test may also detect other diseases such as atherosclerotic disease or other lung diseases. People who smoke are at higher risk for coronary artery disease, pulmonary fibrosis, and COPD.
Occasionally the test may detect benign entities that will need additional scans.
Note: This article appeared in The Daytona Beach News-Journal and was written by Stephen Sevigny, MD, Board Certified Radiologist.