The results of the I-ELCAP polling project were first published in the Lancet in 1999, and then in the New England Journal of Medicine in 2006. The I-ELCAP study showed that early diagnosis of lung cancer among high-risk patients, such as individuals between the ages of 50 and 80, who are current or former smokers, using low-dose computed tomography (CT) scanning followed by early treatment options could cure 80 percent of the cancers.
In November 2010, the National Cancer Institute (NCI) released results from the National Lung Screening Trial (NLST) that confirmed the results of the I-ELCAP study. The NSLT found that CT screening can reduce the number of lung cancer deaths in a high-risk population by as much as 20 percent. This was good news for a patient population that rarely has anything to cheer about.
But how do we make sense of the difference between the I-ELCAP estimated curability and the NLST mortality reduction? Clearly, the two measures are inter-related; there cannot be a reduction in mortality unless some participants with potentially fatal lung cancer had been diagnosed early through CT screening followed by early treatment. But why the big difference?
The answer lies in understanding the differences between the two trial designs. I-ELCAP estimated the cure rate, which depends on how often a particular regimen of screening leads to curable lung cancer. The parameter itself is a quantitative measure and is independent of the number of screening rounds.
The NSLT tested the hypothesis of no mortality reduction vs. a reduction of at least 20 percent. The design used a specific number of screening rounds and length of follow up. The magnitude of the mortality reduction is directly dependent on these design parameters and not solely related to how well the screening performs or how curable the cancer actually is. The NSLT cannot estimate the full mortality reduction because the number of rounds of screening was limited and the trial was stopped once the 20 percent mortality reduction had been achieved. It is only when sufficient rounds of screening are performed and the follow-up focuses on the time interval where the mortality reduction is expected to manifest that the trial will reflect the curability rate as estimated by I-ELCAP.
Numerous publications document the findings of the I-ELCAP member’s work. Additional findings include:
- Curability of Stage I lung cancer is 80-90%
- Annual CT screening allows at least 80% of lung cancers to be diagnosed at Stage I.
- CT screening creates a counseling opportunity that results in greater smoking cessation
- Costs of CT screening for lung cancer compare favorably with breast, cervical, and colon cancer screenings.
Our research is ongoing, incorporating larger pools of patient data to reaffirm early findings and suggest new directions for future research and recommendations. I-ELCAP has and continues to receive a great deal of praise from our peers, physicians, academics, patients, and the media.