Panel Reviews Benefits and Harms of CT Scans for Lung Cancer ScreeningA panel of experts has reviewed the evidence regarding the benefits and harms of screening for lung cancer with low-dose computed tomography (CT) and concluded that the technology may benefit some individuals at high risk for lung cancer. But the panel cautioned that many questions remain about the potential harms of screening and how to translate screening into clinical practice.
The review, published in JAMA on May 20, was a collaborative effort by the American Cancer Society, the American College of Chest Physicians (ACCP), the American Society of Clinical Oncology (ASCO), and the National Comprehensive Cancer Network.
"We found that CT screening has the potential to reduce lung cancer deaths in some smokers and former smokers when utilized appropriately, but there are many unanswered questions about its risks and whether it will work as well in clinical practice as it has in carefully conducted trials," lead author Dr. Peter B. Bach of Memorial Sloan-Kettering Cancer Center said in a statement.
Based on the results, ASCO and ACCP issued a clinical practice guideline for physicians. The guideline suggests that screening be offered to smokers and former smokers aged 55 to 74 who have smoked for 30 pack years and either continue to smoke or have quit smoking within the past 15 years. Individuals who do not belong to these categories or who have serious health conditions that would limit their life expectancy, rule out curative treatment for lung cancer, or both, should not be offered screening.
In addition, screening should be done at facilities that can deliver the level of care provided to participants in the National Lung Screening Trial (NLST). Results from that trial, which were published last year, showed that screening with low-dose CT led to a 20 percent reduction in lung cancer deaths compared with chest x-ray screening.
The NLST investigators noted that the harms of screening should be considered in future clinical recommendations. Potential harms include false-positive results and unnecessary follow-up procedures, such as needle biopsies and bronchoscopies.
Dr. Bach and his colleagues categorized the strength of the recommendations in the new guideline as "weak" based on "moderate" or "low" quality research data. However, additional results from the NLST and from European studies will appear in the coming years. When these data become available, the clinical practice guidelines will be reassessed, Dr. Bach explained.
"As we understand more about the risks and the benefits [of low-dose CT screening], the calculus is very likely to change," he wrote in an e-mail message. "In which direction, it is impossible to predict."
Further reading: "Crunching Numbers: What Cancer Screening Statistics Really Tell Us"