Enrollment in the National Lung Screening
Trial (NLST), which was projected to have begun this spring, has been delayed.
The National Cancer Institute (NCI) apparently wants to ensure that it makes
every effort to listen to the complaints of critics.
An NCI spokeswoman says
there is no official start date for the trial, which is expected to enroll
50,000 people. The NLST is a randomized, controlled trial in which individuals
at high risk for lung cancer will be randomly assigned to either low-dose spiral
computed tomography (CT) or chest x-ray. The study will be large enough to
determine if there is a 20% or greater difference in mortality between the two
Much of the criticism of the NLST has come from radiologist
Claudia Henschke, MD, a respected crusader for lung cancer CT screening. She
vehemently argued her case, most recently, in April during an appearance before
the House Ways & Means health subcommittee. Henschke, a radiology professor
at Weill Medical College, Cornell University in New York, is the principal
investigator for the Early Lung Cancer Action Program (NY-ELCAP), a 10-year-old
trial with a substantially different design than the NLST.
In her appearance
before the health subcommittee, Henschke argued that a randomized trial would
take too long, be too expensive, and would be "unlikely to provide an
answer as it has the same design flaws that recently caused the firestorm about
mammography screening." She asked members of the subcommittee to force the
NCI to change its trial design. other notable opposition to the NLST came when
NCI’s Board of Scientific Advisors voted on the trial on November 14, 2001;
the vote was 17-8 in favor with one abstention.
Denise Aberle, MD, professor of thoracic imaging and vice chair
of research in the department of radiology at UCLA School of Medicine, and
principal investigator of the American College of Radiology Imaging Network
component of the NLST, insists that there is no substitute for a large,
randomized trial. "Unlike treatment trials, in which survival is an
appropriate outcome measure, we cannot look at survival, case-fatality, or other
surrogate end points such as tumor size to determine the benefits of
screening," she states.