Weighing the Risk of Being Saved by the Lung Cancer Scan

Ingrid G. Hein


May 24, 2018

"If you smoked, this new lung cancer screening could save your life."

Even though she quit smoking years ago, Eva Marie fits the profile of someone at high risk for lung cancer. She is shown atop a "mountain" of smoked cigarettes, illustrating how she has triumphed over the bad habit in the American Lung Association Saved by the Scan campaign.

Eva Marie gets scanned for lung cancer frequently. "It's like getting a mammogram for me. It's that important. Technology has changed a lot. The chances of survival, and living a good life, are so much greater than they were even 10 years ago," she says in her testimonial.

Launched in August 2017, the Saved by the Scan campaign sends a strong warning to current smokers or those who quit in the last 15 years: If you have a 30-pack-year history of smoking (the equivalent of a pack a day for 30 years, or 2 packs a day for 15 years), and are currently 55 to 77 years old (up to 80 years old for private insurance), you are considered at high risk for lung cancer, which could kill you.

But there is hope: People who fit the high-risk profile are eligible for a low-dose CT scan—a test that saves lives, the ads promise.

In the National Lung Screening Trial (NLST),[1] lung cancer mortality was reduced by 20% in patients at high risk for lung cancer screened by CT compared with single-view posteroanterior chest radiography.

More than 8 million Americans meet the guidelines for a low-dose CT scan, according to American Lung Association president Harold Wimmer, and for them, it would be covered by Medicare or by private insurance. "If we reach those that are eligible, we could save 12,500 lives," he told Medscape.

The target audience is responding. Since the campaign launch, over 100,000 people have taken the online quiz to check their eligibility. "Seventy-five percent of those are at high risk for lung cancer, so we are reaching the right people. Our hope is they will take the initiative to be screened," Wimmer said.

But experts caution that screening is a decision that should be weighed carefully. The campaign materials encourage those who are eligible to talk to their doctor, but they omit a vital piece of information: A CT scan comes with risk as well as benefit and, in some cases, has done much more harm than good—even people who never had cancer have died as a result of invasive tests following screening.

CT Scan Eligibility Based on NLST Criteria

From the more than 50,000 participants in the NLST, there were 247 deaths from lung cancer per 100,000 person-years in those who were screened with a low-dose CT scan and 309 deaths per 100,000 person-years for those in the radiography group—a 20% relative risk reduction (95% confidence interval, 6.8-26.7; P=.004).

There are economic forces at work here. It's a perfectly rational decision not to be screened.

It was the first and only study to show a reduction in lung cancer mortality for screening with a low-dose CT. None of the previous studies, including the DANTE trial[2] (1264 people in the CT group), the NELSON trial[3] (7155 in the CT group), and the Danish DLCST trial[4] (2052 in the CT group), saw a mortality reduction with low-dose CT screening compared with no screening [or baseline X-ray].

The NLST investigators reported significant mortality related to the screening process. Study authors wrote, "The frequency of major complications varied according to the type of invasive procedure. A total of 16 participants in the low dose CT group (10 of whom had lung cancer) and 10 in the radiography group (all of whom had lung cancer) died within 60 days after an invasive diagnostic procedure."

"There's a double-edged sword to screening," H. Gilbert Welch, MD, from Dartmouth Institute for Health Policy & Clinical Practice, explained to Medscape. "The chances that people are hurt by interventions they don't need are relatively high. If I were a smoker, I'd stay the hell away from it—but, of course, I would also stop smoking."

His stance on screening is steadfast. He doesn't think it's worth the risk most times. "Tell them the truth," he said. "It's a close call, and there's money in it. There are economic forces at work here. It's a perfectly rational decision not to be screened."

Welch is outspoken against excessive cancer screening because of the problem of incidental detection. In a study published this year in JAMA Internal Medicine ,[5] he looked at the incidence of nephrectomy in relation to regional CT screening and concluded that, "those residing in high-scanning regions face a higher risk for nephrectomy, presumably reflecting the incidental detection of renal masses. Additional surgery should be considered one of the risks of excessive CT imaging."

Evaluating Risk

David Midthun, MD, from Mayo Clinic, who has written several papers on the definition of a high-risk lung cancer patient, says that the risks of CT scanning are important to discuss with patients—they are a significant part of the finding in the NLST. "Six people walked in asymptomatic, feeling fine, and were dead in 2 months because of a procedure from which they didn't recover," he explained. "It may sound like a small number in the total 53,000 who were screened, but if you're one of those six, [the] percentage doesn't matter."

He points out that these numbers would be unacceptable for other types of cancer screening. "The issue with the lung is that risk of further evaluation is significantly higher than it is for the other organs."

Midthun agrees that there is proof that lives can be saved with lung cancer screening, but the measure of the benefit is based on a 20% mortality reduction in people at high risk. "Therein lies the problem," he said. "How do you define high risk?"

He explained that the NLST criteria for high risk (age and pack-years smoked in the last 15 years) are indisputable but not definitive. Better methods have emerged since that trial.

The Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial investigators updated their model to better identify people at high risk for lung cancer and applied it to the NLST population.[6] The results showed that the modified PLCO model (PLCO-M2012) had greater sensitivity (83.0% vs 71.1%; P<.001) and a better positive predictive value (4.0% vs 3.4%; P=.01), with similar specificity (62.9% and 62.7%, respectively; P=.54) to the NLST criteria. This model missed 41.3% fewer lung cancers.

The PLCO-M2012 model included age, level of education, body mass index, family history of lung cancer, chronic obstructive pulmonary disease, chest radiography in the previous 3 years, smoking status, history of cigarette smoking in pack-years, duration of smoking, and quit time.

Midthun believes that it's important to look at both the NLST and PLCO predictors to decide if someone is at high risk and would benefit from a scan.

"You can't base the decision on whether they can be reimbursed," he says. That means that some patients will have to pay out of pocket for a scan—or maybe some insurance companies will reimburse, he notes.

He understands why the campaign chose the simple most predictive criteria. "To do anything different from age and pack years gets pretty complicated; you need more data," he explains. "So if you're starting a national campaign and want to keep things simple, rather than be perfect and hit a home run... Do you go after low-hanging fruit or all [the] fruit you can pick?"

"If you’re looking at it from a public health standpoint, using the NLST criteria, you would save somewhere in the range of 12,000 lives per year if everyone got screened," he explains, assuming it cut nearly 10% of the 158,000 deaths annually from lung cancer. By everyone being screened, Midthun means all 8-9 million Americans who meet high-risk criteria, which is unlikely, "so screening alone isn't going to be the solution," he notes.

Lung Cancer Screening Riskier

An article by the American Cancer Society, posted shortly after the Saved by the Scan campaign was launched, does note the risks, pointing out that, "one drawback of a CT scan is that it finds a lot of abnormalities that turn out not to be cancer but that still need to be checked out to be sure. This may lead to additional scans or even more-invasive tests such as needle biopsies or even surgery to remove a portion of lung in some people. A small number of people who do not have cancer or have very early stage cancer have died from these tests."

When asked about the lack of such information in the Saved by the Scan campaign materials, American Lung Association president Wimmer explained that, "As new information comes forth, we will update our information on site. We want to make sure the individuals have all the information on pros and cons.... That's why we encourage them to talk to their doctor about that."

The plan is for the campaign to continue into 2019. Wimmer said that, to date, the American Lung Association has invested $3 million in the campaign. Additional funding came through the Ad Council, in the form of pro bono donations. Michelle Hillman, Ad Council's head of campaign development, told Medscape that about $13 million has been donated to the campaign.

For now, the campaign media spending has been focused on TV and outdoor print, including banners in public transport and video storytelling on TV. The Ad Council chooses several health campaigns each year to support, "if it is something that a communications program can help to shape change," she explained. "The fact that there is this new technology that is life-saving means we are bringing news to people—that by time you see symptoms, it's too late."

They decided to focus on former smokers, who feel the accomplishment of quitting but are still at risk; thus, the mountain of stubbed-out cigarettes they've climbed over. "But there is one more thing to do to enjoy this healthy life that you might not have realized. It's simple and it's easy and life-saving, and you probably didn't know about it," added Hillman.

Midthun cautions that, "we have to be responsible." Patients need to understand that they can suffer complications or even death from further investigation of abnormalities found during a scan, he said, "even in cases where no cancer was ever found." His verdict on the campaign is that it "may not be premature—but maybe immature."

Editor's Note: An earlier version of this story incorrectly listed criteria for lung cancer screening per the Saved By The Scan campaign. The criteria are in line with the current USPSTF recommendation.


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