An Early Detection Test for Lung Cancer Could Reduce Deaths by a Quarter

Regular screening of people at high risk of lung cancer because of smoking, using low-dose computed tomography (LDCT), could reduce deaths by a quarter.

Lung cancer remains the leading cause of cancer-related deaths worldwide, causing approximately 1.8 million deaths a year (see Global Cancer Statistics). However, a newly published report suggests that more targeted lung screening could reduce these deaths by a quarter.

• Related topic: Current Cancer Screening Programs: Which Tests Can Detect Which Cancers Early?

Early Detection of Lung Cancer Is Possible With Low-Dose Computed Tomography

Low-dose computed tomography (LDCT) screening of high-risk individuals has been shown to enable lung cancer diagnosis at earlier stages in clinical studies.

This can significantly reduce deaths from lung cancer while also having a substantial effect on quality of life, turning lung cancer from a challenging condition into a treatable one. It also suggests that preventing deaths from lung cancer requires fewer screening examinations than preventing deaths from other cancers.

Who Should Be Screened for Lung Cancer?

People whose smoking history places them at high risk for lung cancer and who are aged 50 to 80 should undergo annual low-dose computed tomography (LDCT) screening of their lungs. 

People who, over their lifetime, have smoked at least 20 pack-years and still smoke, or who have smoked 20 pack-years but quit within the past 15 years, are considered at "high risk" of lung cancer.

Note: One pack-year is defined as smoking an average of 20 cigarettes (or one pack) a day for one year. For example, smoking 1 pack a day for 20 years is calculated as 20 pack-years, while smoking 2 packs a day for 10 years is also calculated as 20 pack-years.

A Study Highlighting the Importance of Early Detection Screening for Lung Cancer

According to the NELSON study, 1 life could be saved for every 320 low-dose computed tomography (LDCT) screening examinations performed.

The study showed that one life could be saved for every 864 colorectal cancer tests and for every 645 to 1724 breast cancer tests.

However, lung cancer screening is not as widespread as breast and colorectal cancer screening. A report was published by the “Lung Ambition Alliance,” which came together to “eliminate lung cancer as a cause of death” and whose founding partners are the International Association for the Study of Lung Cancer (IASLC), Preventive Health and Global Lung Cancer Coalition and AstraZeneca. The report suggests that national governments should assess the case for implementing targeted lung screening on a large scale.

Why Is It Important to Move Diagnosis to Earlier Stages?

If diagnosis is made earlier, a higher proportion of patients will have potentially operable Stage I or Stage II disease. The "bottom line" is that LDCT can significantly reduce lung cancer mortality (death rates) over 5 years. This matters because, although targeted drugs and immunotherapies have improved lung cancer survival, it is "not at the desired level." These drugs have produced a "clinically meaningful" survival benefit, but "tumors develop resistance to drugs" and patients consequently continue to "lose their lives to this disease." The vast majority of tumors detected by screening are found at the first and second stages, when 5-year survival is "much higher."

The published report notes that many existing lung cancer screening approaches diagnose cancer at an advanced stage, when the patient's treatment options are limited. Only 20% of patients are diagnosed at the first stage, when the probability of 5-year survival is 68% to 92%, while more than 40% are diagnosed at the fourth stage, when 5-year survival is around 20%. The report also states that LDCT screening enables early detection of difficult-to-detect conditions such as chronic lung disease and cardiovascular disease and reduces healthcare costs.

Lung Screening Should Be Expanded

According to the report, only a few countries worldwide (the USA, Japan, South Korea, Croatia, Poland and Australia) have committed to launching nationwide screening programs. The report also calls for large-scale implementation of LDCT screening in high-risk populations. This approach needs to be a reliable tool for identifying those at highest risk, incorporate general lung cancer prevention messages into screening, and ensure participation by people who are more susceptible to cancer.