Study: Low Dose CAT Scan Reduces Risk of Lung Cancer Death in Smokers
I wear two hats as a primary care doctor. On one hand, I see myself as a promoter of health. On the other hand, I am in a constant battle against disease.
An instance where I wear both hats though is with smoking and its related diseases. I spend a considerable amount of time educating on both the prevention and cessation of smoking and I also treat patients with smoking-related heart and lung disease. The most feared result of smoking though, is lung cancer and sadly, this happens all too often.
Beyond encouraging people to quit, there's not much in the "win" category for this terrible disease. Screening with periodic chest x-rays have not shown any change in the outcome. For some time, the survival rate 5 years after cancer is discovered in the lungs has been a dismal 15%. Only 15% of people will still be alive 5 years later. Recently, however, some hope for earlier detection and treatment has emerged. The nod was give to low-dose CAT scanning as a screen for the early detection of asymptomatic lung cancer.
Should you as a smoker or your smoking loved ones get this test?
What are the risks and the benefits?
What IS a Low Dose Lung CT?
CT scanning, or "computerized tomography", is an imaging study using radiation to define tissues of different density. Traditionally, CT scanning utilizes a high amount of radiation, adding some risk to the procedure. "Low dose" CT scanning of the lung serves as a quick peek into the chest cavity looking strictly for tumors. This scan protocol delivers a much lower dose of radiation than a standard CT. Any hospital with a CT machine can perform the study and given the new recommendations, most centers are now offering these tests. Some are even offering a low cash pay cost for the scans as a public service.
Several studies have been performed giving merit to performing low dose CT scanning in high risk populations. Most notable was the National Lung Screening Trial. In this study, where more than 50,000 asymptomatic adults aged 55-74 were screened, researchers found a 16% reduction of death from lung cancer and a 6.7% reduction in overall death rate. To simplify, one lung cancer death was averted for every 320 patients screened and one death from all causes was prevented for every 219 patients screened.
What It Means For Us
Screening high risk smokers with low dose CT saves lives. This finding is significant considering that lung cancer causes as many deaths in the U.S. as the next three leading cancers combined. The U.S. Preventative Task Force (USPTF), a conservative government-sponsored panel of experts that looks at the validity of screening and medical interventions recently reviewed this test and gave it a "B" rating.
A "B" rating gives an official recommendation from the USPTF with "a high certainty that the net benefit is moderate to substantial." This means that the Center for Medicare and Medicaid Services can mandate that the service be provided to Americans without charging a copay or applying a cost to an insurance deductible.
Of course, it should be noted that screening for a disease means a willingness to undergo therapy if the disease is found. Though ethically, while quitting smoking should be a consideration in screening, it cannot be a requirement.
Who is High Risk?
The USPTF defines persons at high risk as heavy smokers aged 55-80 with a 30 pack-year or more usage. Pack-years are calculated in packs per day smoked times years used. In other words, one pack per day for 30 year or 2 packs per day for 15 years equals 30 pack years. Those who have quit within 15 years with 30 pack years are considered high risk while those who quit more than 15 years ago are not recommended for screening.
Smoking is the most common cause of the most common cancer. As a primary care doctor, I'll put a plug in that an ounce of prevention (not starting or quitting early) is worth several pounds of cure when it comes to lung cancer. In the interest of catching lung cancer early, however, low dose lung CT is an important new development for screening high risk individuals. Talk to your doctor if you feel you or your loved one may benefit from low dose lung CT.