Controversy dogs lung screening clinical trials

July 1, 2008

Despite setbacks in the laboratory and the press, multislice CT as a possible screening test for lung cancer continues to provoke strong interest in anticipation of findings from randomized multicenter clinical trials that may ultimately judge its value.

Despite setbacks in the laboratory and the press, multislice CT as a possible screening test for lung cancer continues to provoke strong interest in anticipation of findings from randomized multicenter clinical trials that may ultimately judge its value.

The screening protocol has been controversial since Weill Cornell radiologist Dr. Claudia Henschke first launched the International Early Lung Cancer Action Program (I-ELCAP) for CT cancer screening in 2000. Henschke's initial results for the detection of stage I lung cancers appeared promising, but the possibility of high false-positive results encouraged Dr. Stephen Swensen, radiology chair of the Mayo Clinic in Rochester, MN, to question her approach.

Revelations published in The New York Times in March about Henschke's failure to disclose the use of tobacco industry money for the I-ELCAP trials raised questions about her motives.

But proponents of lung cancer screening are not abandoning ship. Controversy aside, clinical evidence will determine if CT lung cancer screening sinks or swims. Dr. Heidi Roberts and colleagues are moving ahead with their own trial at several Canadian institutions.

Thus far, they've screened 4000 people in a program funded entirely by the Princess Margaret Hospital Foundation. Roberts' group published early results, confirming that low-dose CT scans identified lung cancer early (Can Assoc Radiol J 2007;58:4:225-235).

"We made our own decision when we started screening and unanimously decided against approaching tobacco companies because of the implications, or rather perceived implications, that we see in the U.S. media right now," Roberts said. "Our results are quite similar to those of the I-ELCAP regarding baseline findings, including prevalence of nodules and lung cancers, as well as early-stage lung cancer. We do not have long-term data on survival yet; we've only been screening for 4.5 years."

Other major trials are also ongoing, including the 50,000-participant National Lung Screening Trial sponsored by the National Cancer Institute and several in Europe. These long-term trials may not be the last word, but they will help resolve questions about lung cancer screening, according to Roberts.

"If you look into other areas of screening, the biggest one being mammography, there is no definite answer there either," Roberts said. "After many years of working on screening for breast cancer, there are still a lot of issues that are open.