• Low-dose CT scans to screen for lung cancer — along with improvements in treatment — have led to an increase in the number of early-stage diagnoses in the U.S., according to recent study.
• Between 2006 and 2016, the number of lung cancer deaths in the U.S. decreased by 4 percent every year.
• The authors concluded that this uptick in early diagnosis is associated with the significant decline in lung cancer deaths in recent years.

Lung cancer deaths are on the decline in the United States, in part due to early detection and diagnosis from screenings, according to a recent study. Researchers from Mount Sinai found that the combination of early screening and follow-ups has led to a significant drop in non-small cell lung cancer (NSCLC) deaths over the past few decades.

“This is the first time a large population-based study has demonstrated decreased lung cancer mortality with early detection — finding cancer in earlier stages — when tumors are smaller and more curable,” said Dr. Raja M. Flores, chair of thoracic surgery at Mount Sinai Health System, in a statement. “This study emphasizes the impact of screening followed by surgical intervention to save lives in people at high risk for lung cancer.”

Lung Cancer and Current Screening Methods

Lung cancer is the second most common cancer in the United States, but is the leading cause of cancer deaths. More than 230,000 new lung cases will be diagnosed in 2022, mainly developing in people ages 65 and older. This number has significantly declined from 2012 to 2016, and lung cancer deaths have also decreased compared to other types of cancer.

Many studies have attributed the decline in deaths to new therapies that have emerged over recent years. Advances in chemotherapy, targeted therapy, and immunotherapy have all been effective for treating lung cancer — specifically in cases of NSCLC.

Early screening is also known to contribute to lower case numbers. The National Cancer Institute conducted a study in 2011 called the National Lung Screening Trial (NLST). The NLST compared two different screening methods for lung cancer — low-dose helical computed tomography (LDCT) and a standard chest X-ray. The study found that people who were screened with LDCT had a 15 percent to 20 percent lower risk of dying from lung cancer than those who were screened with standard chest X-rays.

In 2013, the U.S. Preventive Services Task Force began recommending LDCT scans to screen people who are at a high risk for lung cancer. LDCT scans find cancer in 24.2 percent of the scans, compared to chest X-rays finding lung cancer in only 6.9 percent of scans.

“If all people who were eligible to be screened received the low-dose CT scan, which has a dose of radiation comparable to an annual mammogram, we could save up to 80 percent of those people,” Dr. Claudia Henschke, said professor of diagnostic, molecular and interventional radiology at the Icahn School of Medicine at Mount Sinai.

With this, researchers from Mount Sinai set out to determine the impact these findings have had on lung cancer cases over the past decade since the NLST was conducted.

Early NSCLC Detection Leads To Fewer Deaths

The study authors used registries from the Surveillance, Epidemiology, and End Results (SEER) program, which collects information on cancer cases in the United States, along with associated demographic information. They identified NSCLC cases diagnosed between 2006 to 2016, including 312,382 total participants in the study — 28.2 percent of participants were diagnosed at stage 1 or 2, 69.5 percent at stage 3 or 4, and 2.3 percent were missing staging information.

Between 2006 and 2016, the number of lung cancer deaths decreased by about 4 percent every year. The authors found a significant association between the year of diagnosis and stage of cancer. The number of people diagnosed at stages 1 or 2 significantly increased between 2006 and 2016, from 26.5 percent to 31.2 percent. However, the number of people diagnosed with stage 3 or 4 significantly decreased, from 70.8 percent to 66.1 percent.

Taking into account other studies, the authors conclude that LDCT scans appear to be associated with earlier detection of NSCLC and a decrease in associated deaths. However, they noted that the study did not take into account smoking status, exposure to cancer-causing agents known as carcinogens, or genetic mutations found in NSCLC.