CT Lung Screening and Follow-up Protocol

Research published in this month’s American Journal of Roentgenology reported excellent results on a protocol for working up patients with nodules found in CT lung screening. Ever since the National Lung Screening Trial showed a 20% mortality reduction among high-risk patients screened for the disease, criticism has been vocalized due to the potentially large number of false-positive results following diagnostic imaging investigations. Though the possibility of finding cancer outweighs the risk of false positives, the researchers argued that false-positive results could potentially increase the risks and costs of screening, diminishing the benefit of early cancer detection.

This study, which required participants without a history of cancer to have smoked a minimum of 10 pack-years, concluded with positive results. According to the research, the algorithm produced low false-positive rates, and could make the establishment of large-scale CT screening programs more feasible.

Follow-up CT protocols in lung cancer screening – once a finding is discovered and needs to be evaluated over time or even just routinely on a schedule – is one area ripe for ultra low-dose CT technique. With this technique, we really can see doses reduced by 40 – 80% among these applications! Accepting higher noise in images, very low-dose kVp (in the 80-100 range), and aggressive application of iterative reconstruction techniques can produce diagnostic CT results at breathtakingly low doses.

NCCN Confirms Importance of Lung Cancer Screening

Recently, the National Comprehensive Cancer Network has come forward in favor of lung cancer screening with low-dose CT. The NCCN is the first professional organization to perform the comprehensive review and update their recommendations to promote lung cancer screening.

This update further validates the key concept that high risk patients benefit from screening. High risk patients for lung cancer diagnoses are those who are multiple pack year smokers for 25 of more years. For these individuals, low- dose CT screening reduces the number of lung cancer deaths by 20 percent.

While we don’t really know the full cost of a screening program – such as the costs of working up false positive CT findings,  the benefit in lives saved seems to justify considering screening now.

Fortunately, the CT technique for screening is low dose and involves low radiation dosage.