Low-dose computed tomography, also known as a low-dose CT scan, is a screening tool that can rotate in a spiral motion and take three-dimensional X-rays of the lungs. It can take a detailed image of small abnormalities to help detect early-stage lung cancer.
There is a warming debate about the efficacy of using low-dose CT scans. Though low-dose CT scans can effectively detect early-stage lung cancer, it might also detect benign and undetermined nodules, causing unnecessary radiation exposure and further follow-up. In addition, excessive low-dose CT scans can have an adverse impact on patients’ physical and mental stress.
Recently, a study published in the journal Annals of Oncology confirmed the efficacy of lung cancer screening. The researchers of the study found that prolong low-dose CT lung cancer screening can reduce 10-year mortality.
In light of the previous National Lung Screening Trial (NLST) has shown that lung cancer screening by three annual rounds of low-dose CT reduces lung cancer mortality. The researchers of the study focused on evaluating the benefits of prolonged low-dose CT screening beyond 5 years, and its impact on overall and lung cancer-specific mortality at 10 years.
Researchers adopted the Multicentric Italian Lung Detection (MILD) trial as their study design, which is the only randomized trial designed to evaluate the value of prolonged lung cancer screening beyond 5 years.
They recruited a total of 4, 099 former or current smokers, and 2, 376 participants were randomized to a screening arm, with further allocation to the annual or biennial screening arm. The remaining 1723 participants were randomized into the intervention group. The median ages for the control arm and intervention arm were 57 and 58; the median pack-years of cigarettes for the two groups were 38 and 39.
Over 10 years of follow-up, 98 participants were diagnosed with lung cancer in the intervention arm and 60 participants in the control arm. It is supervising to found that to diagnose a lung cancer case, a patient needs to receive 154 low-dose CTs and 1.4 PETs. A low-dose CT was found beneficial for the early detection of lung cancer. 50% of lung cancer cases in the intervention arm were Stage I lung cancer, while the figure for the control arm was only 21.7%. Similarly, the lung cancer resection rate was 65.3% in the intervention arm versus 26.7% in the control arm.
About 40 participants died of lung cancer in the invention arm, accounting for 29% of all death. Despite the same number of deaths, lung cancer-specific death in the control arm was 9% higher.
The statistical results show that the low-dose CT screening contributed to a 39% reduced risk of lung cancer mortality and a 20% reduction of overall mortality at 10 years. Furthermore, low-dose CT screening showed improved benefit beyond the 5th year of screening, with a 58% reduced risk of LC mortality, and a 32% reduction of overall mortality.
This MILD trial can be a new confirm for the efficacy of low-dose CT lung cancer screening. It suggests that prolonged low-dose CT screening beyond 5 years can improve the benefits of screening and achieve a significant 10-year mortality reduction.