Largest-Ever Lung Cancer Screening Study Recruits Current and Former Smokers

The University of Texas M.D. Anderson Cancer Center announced Sept. 18 that it is recruiting current and former smokers for the largest lung cancer screening study ever conducted.

M.D. Anderson is among 30 sites across the United States participating in the National Lung Screening Trial. Coordinated at M.D. Anderson by the American College of Radiology Imaging Network and funded by the National Cancer Institute, the study is enrolling 50,000 current and former smokers in the next two years. M.D. Anderson is the only participating Southwest site and intends is recruiting 1,000 current and former smokers.

The eight-year, $200 million trial will compare methods of detecting lung cancer – spiral computed tomography versus standard chest X-ray – and compare the risks and benefits of the two techniques.

Spiral CT, also known as helical CT, utilizes X-rays to scan the entire chest in about 15 to 25 seconds during a single, large-breath hold. During the procedure, the participant lies on a table and both the table and patient pass through a doughnut-shaped scanner. The scanner rotates around the participant and a computer creates images from the scan, assembling them into a 3-D model of the lungs.

Introduced for clinical usage in the early 1990s, spiral CT was first used as a lung cancer screening technique in Japan. Since then, a number of independent trials have been conducted validating the technique.

The National Cancer Institute’s first look into CT as a lung cancer screening method began in late 2000 with the launch of an initial trial comparing CT to chest X-ray. Much smaller than the soon-to-take-place National Lung Screening Trial, the previous study enrolled 3,000 current and former smokers within just two months of the study’s launch. Data from that trial is expected to be released later this year.

Reginald Munden, M.D., associate professor in M.D. Anderson’s department of diagnostic radiology, is the principal investigator for the upcoming National Lung Screening Trial at M.D. Anderson. Therese Bevers, M.D., assistant professor in the institution’s department of clinical cancer prevention, serves as co-principal investigator.

“This historic trial follows M.D. Anderson’s success with other large NCI-sponsored trials that have advanced our understanding of cancer prevention strategies,” says Bevers, who is also the director of the institution’s cancer prevention center. “With this study, we are given the unique opportunity to determine if there is a detection mechanism that reduces a person’s chance of dying from lung cancer in a group of individuals at increased risk for the disease. Each year, lung cancer kills more people than cancers of the breast, prostate, colon and pancreas combined because the cancer is often found after it has spread.”

Lung cancer, which is most frequently caused by smoking, is the leading cause of cancer-related deaths in the United States. American Cancer Society figures estimate the disease will claim 155,000 lives this year.

Currently, guidelines for lung cancer screening do not exist, as no technology – including chest X-ray and spiral CT – has proven effective in reducing a person’s chance of dying from the disease.

“There is a tremendous need to establish an early detection mechanism for lung cancer that can extend peoples’ lives as well as reduce the overall mortality rate from this disease,” says Munden. “However, spiral CT has been shown to be better at detecting tumors than conventional chest X-rays, especially cancers smaller than one centimeter.”

The need for a large, randomized controlled study – the ‘gold standard’ of research studies – to confirm the benefits of spiral CT is paramount, Munden says.

“Before NCI’s first trial, all trials involving CT were nonrandomized and uncontrolled. Despite earlier studies suggesting CT works, we really don’t know if CT is any better than chest X-ray at increasing survival. With a comprehensive trial such as this one, we will learn an answer to the most important public health issue: Does spiral CT reduce lung cancer deaths?”

Prospective participants, must be healthy men or women ages 55 to 74 who currently smoke or who smoked heavily for many years; at present, must not be receiving treatment for any type of cancer other than nonmelanoma skin cancer; have no history of lung cancer; and must not have had a CT scan of the chest or lungs within the last 18 months. Potential participants will go through a process known as informed consent, during which they learn about the trial in greater detail before deciding whether to participate.

Once a participant enrolls, he or she will be randomly assigned to receive either a chest X-ray or a CT scan each year for three years. M.D. Anderson radiologists will review participants’ spiral CT or chest X-rays. Test results will then be mailed to both the patient and the patient’s personal physician. Participants also will be contacted periodically so that quality-of-life surveys may be conducted.

For those with positive chest X-rays and suspicious CT scans that might be cancer, M.D. Anderson will notify the participants and their primary care physicians and recommend specific follow-up care, Munden says.

Although the CT and chest X-rays will be provided at no charge for all trial participants, should lung cancer and/or other abnormalities be found via screening, additional follow-up tests or recommended treatment would not be financially covered by the trial.

The National Cancer Institute reports recent studies that indicate upward of 70 percent of current and former smokers’ screening CT scans will show abnormalities. While many of these abnormalities – such as scars from smoking and areas of inflammation – are not lung cancer, some of these conditions may mimic lung cancer on scans and thus may require additional evaluation such as further radiology studies, lung biopsy or even surgery.

Conventional wisdom, Munden adds, suggests that the smaller the tumor, the more likely the chance of survival but, to date, no scientific evidence has shown that screening or early detection of lung cancer actually saves lives.

“With the size and scope of this trial, we will be able to provide the evidence needed to determine whether spiral CT scans are better than chest X-rays at reducing a person’s chances of dying from the disease.”

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©2006 Texas Medical Center

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