BECAUSE LUNG CANCER occurs deep inside the body, it’s often not recognized until symptoms begin. These symptoms can take many years to develop, and by the time they surface, the cancer typically has progressed to stage 3 or 4. The later the stage that a cancer is detected, the harder it is to treat, and this is a big reason why lung cancer remains the deadliest cancer in the United States.
The American Cancer Society reports that about 14 percent of all new cancers are lung cancers, and that in 2018 an estimated 154,050 people will die of lung cancer. The American Lung Association reports that the overall five-year survival rate for all forms and stages of lung cancer is about 55 percent.
While these statistics paint a grim picture, they don’t tell the whole story. Within that overall survival rate lies a lot of nuance; for lung cancers detected in stage 1 or 2, the survival rate is much higher. Depending on the substage, the ACS lists five-year survival rates ranging from: 68 to 92 percent for stage 1 non-small cell lung cancer; 53 to 60 percent for stage 2; 13 to 36 percent for stage 3; and 1 to 10 percent for stage 4. Therefore, it would seem that early detection could be the key to improving the overall survival rate for lung cancer.
But how can lung cancers be detected earlier? Screening individuals at higher risk of developing the disease is perhaps the best way to find cancers while they’re more treatable. “Screening is the use of tests or exams to find a disease in people who don’t have symptoms. Regular chest X-rays have been studied for lung cancer screening, but they did not help most people live longer,” the ACS reports. More recently, researchers in the National Lung Screening Trial, a massive look at 53,454 current or former heavy smokers aged 55 to 74, compared low-dose helical computed tomography scanning, a form of imaging, to standard chest X-rays. The trial, which was conducted by the American College of Radiology Imaging Network, launched in 2002. Results were published in 2011 and found that participants who received the low-dose CT scans had a 15 to 20 percent lower risk of dying from lung cancer than participants who received standard chest X-rays.
“That is the biggest mortality benefit that we’ve ever seen in any intervention we’ve been able to do for lung cancer,” says Dr. Andrea B. McKee chair of radiation oncology at Lahey Hospital and Medical Center’s Sophia Gordon Cancer Center in Burlington, Massachusetts.
These results led to the development of screening guidelines by several organizations. The guidance from the U.S. Preventive Services Task Force and the American Cancer Society are perhaps the most widely known, but the American Association for Thoracic Surgery, the American College of Chest Physicians and the National Comprehensive Cancer Network offer screening guidelines as well. Each set of recommendations varies slightly – some recommend that screening stop at age 74, others extend the eligible age to 80 and there are variations based on the length and intensity of the person’s smoking history. So when you ask whether you should be screened for lung cancer, in part, the answer depends on which organization’s recommendations you look to for guidance.
The reason for these variations is not that these organizations are assessing different studies or data, but rather that they’re interpreting the findings in slightly different ways. “There’s only so many publications and trials and retrospective reviews, but [these organizations]might have a different way of combining that data in order to make a recommendation. That’s why you’re getting different results,” McKee says, and this variation has led to some confusion among people who should potentially be screened. Add to that the fact that these organizations are continually updating and revising their recommendations, and it’s no wonder that many people aren’t quite sure whether they should be getting annual screening for lung cancer.
However, some generalizations can be made. If you’re between the ages of 55 and 80, are currently an active smoker or were a heavy smoker with a 20- to 30-pack year history (a pack year is calculated by multiplying the number of packs of cigarettes smoked per day by the number of years the person has smoked), you should speak with your doctor about whether screening is right for you.