Commentary: Lung cancer screening now a routine for smokers

Medical screening tests are done to save lives.

Most people know about the importance of screening mammography in the fight against breast cancer and colonoscopy in the prevention of colon and rectal cancer. These tests have become routine in the fight against cancer.

Now added to the list is a screening test that can detect one of cancer’s deadliest types — lung cancer.

Lung cancer remains the biggest cancer killer in the United States, claiming about 160,000 lives a year, more than breast, colon and prostate cancers combined.

Early detection of lung cancer is difficult without a screening exam. Once an individual develops signs or symptoms of lung cancer, it is often too late for a cure or long term survival. “Screening” refers to testing those at risk for a disease, but without signs or symptoms of the disease.

Unlike mammography, recommended for all women over the age of 40-50, and colonoscopy, recommended for most people over age 50, current recommendations for lung-cancer screening are limited to those at highest risk.

The American Cancer Society and United States Preventive Services Task Force among other organizations now recommend smokers and former smokers at high risk for lung cancer get annual low-dose CT scans starting at age 55.

High-risk patients include current or former smokers who have smoked at least the equivalent of at least one pack a day for 30 years (30 pack-years). Because the risk of lung cancer decreases in former smokers, screening is recommended only for former smokers who have quit within the last 15 years.

“Pack years” is a way to quantify how much a person has smoked, obtained by multiplying packs per day by the number of years smoked. A pack-a-day smoker for 30 years has a 30-pack-year smoking history, as does a two-pack-a-day smoker for 15 years or a half-pack-a-day smoker who has smoked for 60 years.

If a lung cancer is found while still limited to the lung, the five-year survival rate can be more than 70 percent with treatment.

When lung cancer has progressed and is detected with the development of symptoms, the five-year survival rate is less than 15%.

The National Lung Screening Trial, a large clinical trial published in the New England Journal of Medicine in 2011, showed annual screening of heavy smokers or former smokers reduced their likelihood of dying from lung cancer by 20%. Since lung cancer causes so many deaths in smokers, screened smokers were 7% less likely to die from all causes over the average six and a half year follow up period.

Low-dose CT is the only effective way to detect lung cancer early, setting patients on a path to a better outcome.

It is important for individuals with heavy smoking histories to meet with their doctors and discuss the risks and benefits of lung cancer screening and whether the test makes sense for them. For smokers who develop lung cancer, early detection with a screening CT will be the best chance to beat lung cancer.

And it is important to stress — screening with CT scanning can detect an early lung cancer but will not prevent it. Quitting smoking remains the most effective way to reduce the risk of lung cancer.

Stop smoking, get screened and potentially save your life.

DR. WINSTON WHITNEY is a radiologist and program director for Hoag’s Lung Cancer Screening Program.