Shades of gray
Can screening with CT scans save the lives of those at risk of lung cancer? Some say yes, but others say scans might hurt, not help.
For the 42 percent of Americans who smoke cigarettes or once did, a ruling from the state’s highest court last month seemed to offer hope that a simple screening tool could help them ward off advanced lung cancer.
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Even before the court weighed in, advocates had been pressing politicians for money to pay for CT scans for high-risk but asymptomatic people - insurers generally don’t cover the test for screening - particularly since a group of New York researchers published results in 2006 suggesting that screening is saving the lives of smokers, former smokers, and people exposed to secondhand smoke and other hazards, such as asbestos. Some smokers are so convinced of the benefits of CTs they pay the $400 screening fee themselves.
“Our movement is really taking hold,’’ said Joanne O’Connor, cochair of the Lung Cancer Alliance in Massachusetts, which is lobbying legislators for funding. “I wouldn’t want to find out [I had lung cancer] like my sister did when she was already stage four. She died six months later.’’
But even as pressure for CT scanning builds, many of the country’s top cancer specialists are saying not so fast. While advocating early detection may seem like a no-brainer, they dispute the 2006 study and argue that there is no evidence that screeningscans actually save lives. Even worse, they say scanning can be inaccurate and end up harming patients by exposing them to unnecessary procedures and surgery, which carry their own risks.
In fact, the federal government and most major health organizations, including the American Cancer Society and the American Lung Association, recommend against CT screening exams for lung cancer for both smokers and former smokers, calling into question the wisdom of the state court’s ruling.
“There’s an emotional appeal [to CT scanning]; there are people who are dying and you want to help them,’’ said Dr. Steven Woloshin, a professor at Dartmouth Medical School. “But we’ve been fooled again and again in medicine. Right now the only way to make a rational decision is to look at evidence.’’
The debate over CT scanning is of intense personal importance to smokers and former smokers - 96.5 million Americans - and to the thousands of people who get lung cancer each year but who never smoked. Lung cancer is among the most deadly cancers, because it is most often detected after it has metastasized, or spread, leading to a dismal 5-year death rate of 85 percent. The hope is that early detection will improve these terrible odds, just as mammography has decreased mortality for women with breast cancer by alerting them to the need for treatment earlier in the illness. Two large national studies may finally provide definitive answers as soon as next year.
Lynne Petty, 44, of Newburyport, said that as a former smoker she would “absolutely want’’ CT screening if it were covered by her insurance plan. It’s not just the cost that’s kept her from having the test, however, it’s that scanning is not part of mainstream medicine; she would not know how often to get screened or what to expect.
“CT scanning should become as commonplace as a mammogram and colonoscopy where people discuss it like they’re going to dentist’s office,’’ she said. “Did you have your lung scan this year?’’
The search for effective early detection for lung cancer dates to the 1960s. Since then, three randomized trials of lung cancer screening comparing X-rays with regular care found no difference in mortality between the two groups. Contrary to what one would expect, two of the trials actually reported small increases in death rates among patients who were screened; they had more lung cancer surgery, which carries a significant risk of death.
The search for a screening tool was revived in the 1990s with the widespread arrival of CT scans, which are more sensitive than X-rays.
The leading proponents of screening are a group of radiologists from New York Presbyterian Hospital-Weill Medical College of Cornell University, who published a hopeful but controversial study in the New England Journal of Medicine three years ago. Led by Dr. Claudia Henschke, researchers screened 31,567 asymptomatic people at risk for lung cancer using CT scans between 1993 and 2005. They found lung cancer in 484 participants, most of whom had stage 1 cancer. Their estimated 10-year survival rate was 80 percent - an unheard of success rate for people diagnosed with lung cancer.
“I have no doubt we are saving lives,’’ said Dr. Albert Miller, a professor at New York Medical College, and an investigator in the study.
The Massachusetts Supreme Court relied in part on Miller’s expert testimony during the lawsuit brought against Philip Morris by two Massachusetts smokers. Since the 2006 study was published, however, the New England Journal has published three corrections, including one from Henschke revealing that some of the funding for the study came from cigarette-maker Liggett Tobacco.
Dr. Barnett Kramer, associate director for disease prevention at the National Institutes of Health, said the study was faulty, partly because it did not compare patients who were screened to a control group. Kramer, who along with Woloshin, coauthored a rebuttal to Henschke’s study two years ago in the Archives in Internal Medicine, said that screening always will make it appear that people survived longer than those who were not screened.
They put it this way: Imagine a group of patients diagnosed with lung cancer at age 67 who all die at age 70. Their 10-year survival rate is 0 percent. If that same group of patients is diagnosed earlier by CT, at age 59, and they still all die at age 70, their 10-year survival rate is 100 percent. But no matter when they were diagnosed, they still died at the same age.
Annual screening, added Kramer, is always better at picking up slow growing cancers, because aggressive cancers make themselves known with symptoms, so the patients whose cancer was discovered by a CT scan probably would have done better anyway. And they may have cancers that would never become fatal.
“You’re treating and curing people who didn’t need to be treated and cured in the first place,’’ he said, and exposing those people to harm from pneumonia or other risks of surgery.
For now, he said, the best way to lower one’s risk of advanced lung cancer is to stop smoking and not resume - and to stay tuned for the results of the National Lung Screening Trial and the Prostate, Lung, Colorectal & Ovarian Cancer Screening Trial, both sponsored by the National Cancer Institute.
These trials will compare lung cancer death rates for people screened annually with CT scans to those not screened and to those screened with a chest X-ray. “If the trials show that [CT scanning] works that would be wonderful, but they may not,’’ Woloshin said.
Liz Kowalczyk can be reached at kowalczyk@globe.com 
