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Experts say CT scans are effective at catching lung cancer in its early stages. Egor Kulinich/Getty Images
  • Reseachers report that annual low-dose CT scans could increase 20-year survival rates for lung cancer to 81%.
  • Currently, unscreened people with lung cancer have a 5-year survival rate of about 8%.
  • Experts say the benefits of an annual low-dose CT scan outweigh the associated risks of these procedures.

People with lung cancer who receive an early diagnosis via low-dose CT screening have a 20-year survival rate of 81%, according to a study published today in the journal Radiology.

The researchers also report that the survival rate increases to 95% for people diagnosed with stage 1 lung cancer who undergo the screening.

The large-scale, international study included 1,257 participants. The pool of participants included people with less than 10-pack smoking years (1 pack per day for 10 years) and those who never smoked but had exposure to cigarette smoke.

The scientists followed the participants for 20 years.

Lung cancer is the leading cause of cancer-related death worldwide. In the United States, lung cancer is the second most common cancer (not including skin cancer) for both men and women.

It’s estimated that between 10% and 20% of lung cancers in the United States happen in people who have never smoked or smoked fewer than 100 cigarettes in their lifetime.

The average 5-year survival rate for lung cancer diagnosed in latter stages is 8%, according to the American Lung Association.

Only about 23% of lung cancers are diagnosed in the early stages. The 5-year survival rate is 63% for people diagnosed in earlier stages.

In the new study, researchers reported that 81% of the participants who were diagnosed with lung cancer with CT scans were at stage 1.

Researchers said the results of the study show that after 20 years, people diagnosed with lung cancer at an early stage via CT screening have significantly better outcomes. Treating the cancer when it is small and has not yet spread to the lymph nodes can effectively cure the cancer, they noted.

“This new research study is quite fascinating and really positive news for lung cancer clinicians, in that it demonstrates how lung cancer is not an automatic ‘death sentence’ as so many patients fear,” said Sara Belton, PhD, RN, a nurse navigator for Providence Saint John’s Health Center’s Lung Screening Program at the Cardiothoracic Outpatient Clinic in California who was not involved in the study.

“If we can find lung cancer at an early stage, such as Stage 1A, the long-term survival odds beyond five years are very, very good — news which clinicians and survivors alike will welcome,” Belton told Medical News Today.

“To my knowledge, this is also one of the first studies to look at longer-term survival beyond the standard 5-year timeframe that is traditionally used to assess long-term cancer survival outcomes post-diagnosis,” she added. “To see that survival rates are a minimum of 81% and can even be as high as 95% for lung cancer found at Stage 1A, at both the 10-year and 20-year mark, is incredible, and really illustrates the impact of early detection and intervention.”

Experts noted that there are some limitations to the study.

“Most notably, the absence of a control group in this non-randomized study, as well as the challenges in standardization of screening criteria and nodule surveillance algorithms among the International Early Lung and Cardiac Action Program (I-ELCAP) sites,” said Dr. Daniel Sterman, the director of the Pulmonary Oncology Program at NYU Langone’s Perlmutter Cancer Center as well as a professor of pulmonary and critical care medicine at the NYU Grossman School of Medicine in New York.

“Nonetheless, the enduring impact of the I-ELCAP efforts over the past 30 years is the establishment of the concept of low-dose chest CT scan as a means of screening at-risk individuals for lung cancer,” Sterman, who was not involved in the study, told Medical News Today. “The I-ELCAP investigators have undoubtedly saved thousands of lives worldwide with their committed efforts.”

The U.S. Preventive Services Task Force (USPSTF) has determined specific criteria for who could benefit from low-dose CT scans.

“We continue to recommend patients with risk factors according to USPSTF Expanded Criteria for Lung Cancer Screening and outlined recently by the American Cancer Society,” said Dr. Mark Dylewski, the chief of thoracic surgery with Miami Cancer Institute, part of Baptist Health South Florida.

“These changes in the guidelines mean that nearly 5 million more people will be eligible for lung cancer screening each year,” Dylewski, who was not involved in the study, told Medical News Today.

The guidelines state that people aged 50 to 80 years with a 20-pack-year history or who have quit smoking less than 15 years ago should receive a low-dose CT scan every year.

New technology, including robotic technology, allows the ability to biopsy smaller tumors and, therefore, diagnose, and treat at an earlier stage.

“However, this starts with people getting screened early and at regular intervals,” Dr. Ali Z. Jiwani, an interventional pulmonologist at The Orlando Health Cancer Institute in Florida who was not involved in the study, told Medical News Today.

The benefits a CT scan can provide – such as finding cancer in the early stages — far outweigh the risks of the scan, according to the Food and Drug Administration (FDA).

However, experts note that there are some risks.

“There are indeed risks to low-dose CT screening, particularly related to the fact that the vast majority of lung nodules identified on low-dose scans are indeed benign in nature,” Sterman said. “Therefore, among the risks are the potential complications from biopsy or resection of the nodules, which are non-malignant in nature. There is also the risk of radiation exposure from yearly chest CT scans over as long as a 30-year time period. Finally, there is the anxiety of waiting for the results of chest CT scans on a yearly basis with concern for the possibility of identification of lung cancer and the implications for health and survival.”

Another risk is false positives or benign findings.

“It is important to engage an expert clinician to eliminate false positives to prevent unnecessary procedures,” Jiwani said. “Advancements in technology and testing have greatly reduced this risk. Additionally, there are no commercially available FDA-approved biomarkers for lung cancer screening at this time. As work continues on developing screening biomarkers, this may replace or complement the current low-dose CT scan screening recommendations in the future.”

Smoking is the leading risk factor for lung cancer, but it isn’t the only one.

“Aside from smoking, there are other risk factors for developing lung cancer,” Belton said. “These risk factors can include long-term exposure to industrial chemicals, second-hand smoke from home or a workplace, or radon gas in the home, among other risks.”

“If non-smokers have a history of exposure like this, it would be best for them to speak with a healthcare provider, ideally one working in lung cancer care, about their individual risk factors and potential coverage for screening by their health insurance plan,” she added.