February 28, 2003

VICC studies CT, X-rays to detect lung cancer

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VICC studies CT, X-rays to detect lung cancer

Current and former smokers are needed for a new study to determine if screening people with either spiral computerized tomography (CT) or chest X-ray before they have symptoms can reduce deaths from lung cancer.

The National Lung Screening Trial (NLST) will enroll 50,000 participants and will take place at the Vanderbilt-Ingram Cancer Center and 29 other sites throughout the United States.

Sponsored by the National Cancer Institute, the trial is a randomized, controlled study, which is the “gold standard” of research studies. Study participants will be randomly assigned to receive either an initial chest X-ray or a spiral CT followed by repeat examinations annually for two years. Researchers will continue to contact participants annually to monitor their health until 2009.

“Lung cancer will kill nearly 155,000 Americans this year — more than cancers of the breast, prostate, colon, and pancreas combined,” said Dr. John Worrell, associate professor of Radiology and Radiological Sciences and institutional principal investigator in the study at Vanderbilt-Ingram. “Our hope is that this study will lead to saving lives, but only through a carefully done study like this can we be sure that either CT or X-ray is more effective at preventing lung cancer deaths.”

To carry out the trial, NCI is using two research networks funded by the Institute: one network has been conducting a screening study called the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial, and the other is the American College of Radiology Imaging Network (ACRIN), a network of researchers who conduct imaging studies. In addition, NCI is collaborating with the American Cancer Society to organize grassroots recruitment efforts at NLST sites.

Cigarette smoking is the most important risk factor for development of lung cancer, the nation’s leading cancer killer. The estimated 90 million current and former smokers are considered to be high risk for this disease.

When clinically detected, lung cancer has frequently spread outside the lungs. Spiral CT, a technology introduced in the 1990s, can pick up tumors well under 1 centimeter (cm) in size, while chest X-rays detect tumors about 1 to 2 cm in size.

“Conventional wisdom suggests that the smaller the tumor when it is found, the more likely the chance of survival — but that remains to be proven,” Worrell said. “Because of the number of individuals participating and because it is a randomized, controlled trial, NLST 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 lung cancer.”

Spiral CT uses X-rays to scan the entire chest in about 15 to 25 seconds, during a single breath hold. A computer creates images from the scan, assembling them into a cross sectional model of the lungs. More than half of the hospitals in the United States own a spiral CT machine and routinely use them for staging lung and other cancers — that is, determining how advanced the cancer is. Recently some hospitals have begun performing spiral CT scans as a new way to find early lung cancer in smokers and former smokers. However, no scientific evidence to date has shown that screening or early detection of lung cancer with either spiral CT or chest X-rays actually saves lives.

Participants in NLST will receive lung cancer screenings free of charge. Men and women may be able to participate in NLST if they meet the following requirements:

• Are current or former smokers ages 55 to 74.

• Have never had lung cancer and have not had any cancer within the last five years (except some skin cancers or in situ cancers.

• Are not currently enrolled in any other cancer screening or cancer prevention trial.

• Have not had a CT scan of the chest or lungs within the last 18 months.

Additionally, participants can receive referrals to smoking cessation programs if they are interested in quitting smoking.

Persons interested in learning more about participating in the trial can call Vanderbilt NLST at 1-800-988NLST (6578).