Lung cancer remains the leading cause of cancer deaths in the United States, and will remain so for the foreseeable future. That makes answering the question whether or not the early detection of lung cancer with CT scans can in fact reduce the risk of dying from this killer disease all the more important.
Over the past two days, the American Cancer Society has hosted a meeting of experts in Washington DC to answer the question of whether there is anything we can do to accelerate our knowledge as to whether or not lung CT scans really reduce deaths from lung cancer.
The conclusions of these experts were important. But the meeting was not without some controversy when it came to assessing the value of another large United States clinical trial that has been used by many to promote lung cancer screening with CT scans in current or former smokers.
During the course of the meeting, the panel of experts was asked to answer several questions.
Basically, what the American Cancer Society wanted to know was whether there was value in combining the results of all the trials, in an effort to get an earlier answer than would otherwise be possible to the question of whether or not lung cancer screening with CT really does work in reducing deaths.
There are several large studies presently underway in the United States and Europe designed to answer this question.
The National Lung Screening Trial is the largest, with over 53,000 people in the United States participating in the trial. Half of the participants will have an annual chest x-ray for several years, and the other half will receive CT scans of the lung every year for a similar time period. The goal of the study is to find out whether or not the CT group has a lower death rate from lung cancer. The results hopefully will be available in 2010 or 2011 according to information presented at the meeting.
There are currently five smaller trials looking at CT scans as a screening test for lung cancer underway in Europe, and a sixth one is in the planning stages. These studies compare CT scans to “usual care,” which means no routine screening test for lung cancer either with a CT scan or a chest x-ray.
Without going into a lot of detail, after hearing extensive discussion about the various trials from both United States and European investigators, the panel came back this morning with their report and recommendations.
Simply stated, they did not encourage the investigators to pool their data at this time. In the panel’s opinion, that wouldn’t be helpful. In fact, the panel stated, early pooled analysis may lead to an incorrect interpretation or answer to the question about the effectiveness of lung CT screening.
Why is this so important?
Getting the answer right is critical, since this is not just a matter of “another clinical trial.” The results of these research programs will influence public health policy around the globe for years to come when it comes to knowing whether or not lung cancer screening with CT can reduce deaths.
The panel did open the door for further discussions among the various trial leaders about how they can better understand each others’ trials, and how this may lead in the future to a pooling of the data if the opportunity presents itself. But the overall conclusion was this is not the time to do so.
There was another study that was also discussed during the meeting. That study, called the I-ELCAP trial was reported in October 2006 in the New England Journal of Medicine.
The I-ELCAP trial was not a randomized trial. Smokers and former smokers who participated had serial CT scans to detect early lung cancer. There was no “control” group, which received either a chest x-ray or no test to find lung cancer early to serve as a comparison to the lung CT group.
The data from this trial suggested that screening was effective in dramatically reducing the risk of death from lung cancers diagnosed by lung CT scans.
This trial is an important one in the lung cancer screening world because it has been held out by some as proof that CT scans work in reducing lung cancer deaths. Some lung cancer advocates have been adamant that lung cancer screening be promoted based on the results of this trial.
But not everyone agrees. Other studies have been published which refute the conclusions of the I-ELCAP studies.
The American Cancer Society, along with other organizations, have maintained that we need better evidence before endorsing CT scans to find lung cancer early. (For our current recommendations, see information on lung cancer screening at www.cancer.org)
The problem with the I-ELCAP trial is that it has been touched with controversy.
Dr. Otis Brawley—the Chief Medical Officer of the American Cancer Society—summarized that controversy in a letter distributed at the opening of the meeting yesterday:
“(I-ELCAP) was partially funded by the tobacco industry and this was not openly disclosed in publications. Additionally, some of the investigators had financial interests in CT scanning technology which were not disclosed in publications…All of these facts, and the (principle investigator’s) admission that one site violated the protocol, has led some screening experts to hold this trial’s data suspect. Many worry about the validity and reproducibility of the I-ELCAP data.”
Today, Dr. Brawley called for an audit of the I-ELCAP data. He indicated that a validation of the data would go a long way towards providing useful data that he would have confidence in. Absent that audit, the conclusions of the trial remain suspect.
(The I-ELCAP investigators were invited to attend the meeting, but declined the invitation to participate.)
So the controversies continue, and we will have to wait for the conclusion of the NLST trial in the United States before we will hopefully have an answer to the question of whether or not early detection of lung cancer really saves lives.
In the meantime, the American Cancer Society will be calling on the lead investigators and supporters of the various ongoing trials to work together and understand the complexities of each trial, so that the information from these various research studies can by pooled if the need arises in the future.
These are complicated issues and complex questions. Given the impact of smoking on the incidence of cancer, it is important we get the right answer. For now, our experts tell us that staying the course is the best thing to do.
Hopefully, we won’t have to wait too long. The health of many may well rest on the answer to the question of whether or not this sophisticated technology can in fact reduce deaths from one of our major international killers.