A Tale of Two Studies

November 11, 2010

All trials are not equal, even those conducted by the NCI. It’s all about design, according to leading lung cancer specialist.

All trials are not equal, even those conducted by the NCI. It’s all about design, according to leading lung cancer specialist.

NCI-Sponsored Study Finds Increased Risk of False-Positives in CT Lung Cancer Screening

Results of a study published in the Annals of Internal Medicine [Ann Intern Med 152:505-512, 2010] indicate that the risk for false-positive results of CT lung cancer screening tests is substantial. Led by Jennifer M. Croswell, MD, researchers from NCI sought to quantify the cumulative risk in a 1- or 2-year lung cancer screening exam, based on at least one false-positive finding. In addition to determining the rates of false-positive findings, the investigators identified rates of unnecessary diagnostic procedures that are potentially brought on by these false-positive findings.

The randomized controlled trial of low-dose CT vs chest radiography (ClinicalTrials.gov registration number: NCT00006382) found that the risks of false-positive results of lung cancer screening tests are substantial after only two annual examinations, particularly for low-dose CT. The authors recommended further study of resulting economic, psychosocial, and physical burdens of these methods.

Frederic Grannis said:
There should be no surprise when badly designed research produces poor results.  When you design a screening study without an effective diagnostic and treatment algorithm, as did the NCI investigators, an unnecessarily high risk of diagnostic procedures and operations may be expected.  When lung cancer screening is performed in the context of a well-designed diagnostic and treatment algorithm, as in the case of the IELCAP study and European studies based upon the same protocol, the risk of invasive biopsy and operation is much lower.

When you dither and postpone population lung cancer screening while awaiting results from NCI trials, (results of the PLCO trial will be published in 2015, 23 years after the trial was started) you get not a risk, but a guarantee that 160,000 people will die in the U.S. next year and every year subsequently until screening is implemented.

When you screen high-risk smokers and ex-smokers using the IELCAP screening regimen, you can expect that 79% of patients diagnosed with lung cancer will survive at 10 years compared to 15% unscreened lung cancer patients.

Frederic W. Grannis, Jr. M.D.
Long Beach CA

Fast forward!

Lung Cancer Alliance Hails NCI Announcement on CT Screening as Seminal Moment for the Lung Cancer Community

From the press brief: Recently Released Lung Screening Trial Data Confirms Mortality Benefit Lung Cancer Alliance (LCA) hailed today's announcement by the National Cancer Institute (NCI) on the National Lung Cancer Screening Trial (NLST) as a seminal moment for the lung cancer community.

ONCOLOGY editor, James L. Mulshine, MD, Associate Provost for Research and Vice President for Research at Rush University Medical Center in Chicago, IL said: “With this positive trial result, we have the opportunity to realize the greatest single reduction of cancer mortality in the history of the war on cancer.

The official announcement today by Harold Varmus, MD, director of the National Cancer Institute, stated that, “Lung cancer is the leading cause of cancer mortality in the US and throughout the world, so a validated approach that can reduce lung cancer mortality by even 20% has the potential to spare very significant numbers of people from the ravages of this disease.” 

The National Lung Screening Trial (NLST) is a randomized controlled trial of more than 53,000 current and former smokers ages 55 to 74. The trial, launched by NCI in 2002, was officially closed after the data analysis showed screening with low-dose helical computerized tomography (LDCT) reduced mortality from lung cancer relative to screening with chest x-ray (CXR) by 20%.