Many research efforts to address lung cancer strongly recommend getting screened and diagnosed as early as possible, as this form of cancer is the leading cause of cancer-related deaths in the United States.
Clinical evidence estimates that 1 in 3 people die within 90 days after a late lung cancer diagnosis, when the tumor is no longer localized. The standard in lung cancer screening, especially among high-risk individuals (i.e. smokers and ex-smokers), is a CT scan.
A group of scientists from the Netherlands recently published a study in The Lancet Oncology suggesting that low-dose CT screening with increasing intervals can improve timely detection of lung cancer among high-risk patients.
The NELSON trial (detection of lung cancer through low-dose CT screening) sought to determine the efficiency of this approach in reducing 10-year lung cancer mortality.A total of 7,155 participants were examined,with follow-ups after an average of 8.16 years.
The researchers determined their subjects to be high risk and appropriate for the study if they met any of the the following criteria:
- 50 to 75-year-old smokers with a consumption of at least 15 cigarettes a day, for over 25 years
- Those of the same age bracket as above, but have smoked at least 10 cigarettes for more than 30 years
- Former smokers who have quit less than 10 years ago.
The first phase of the trial used CT scans to look for the presence of a nodule and its volume. These findings were labelled as either negative, indeterminate, or positive. Those classified as indeterminate were required to undergo a follow-up screening to confirm a classification under the two other labels.
“We obtained information about all lung cancer diagnoses made during the first three rounds of screening, plus an additional two years of follow-up from the national cancer registry. We determined epidemiological, radiological, participant, and tumor characteristics by reassessing medical files, screening CTs, and clinical CTs,” the authors wrote in their study titled “Detection of lung cancer through low-dose CT screening (NELSON): a prespecified analysis of screening test performance and interval cancer“
Their findings revealed 187 subjects screened were diagnosed with 196 CT-detected lung cancers, while an additional 34 participants were diagnosed later on with 35 interval cancers. Out of these 34 patients, 12 cases were not visible on-screen. The following factors for nondetection were noted:
- Radiological detection and interpretation errors
- Misclassification by the protocol
- Participant non-compliance
- Non-adherence to protocol
Based on their results, the researchers concluded that the NELSON trial showed low-dose CT screening at increasing intervals to be highly specific and sensitive. Furthermore, the authors expect this study’s findings can benefit future and ongoing efforts to enhance screening algorithms, and greatly reduce undetected cancers and misdiagnoses.