Traditionally, lung cancer has only been detected when patients become symptomatic — for instance, if a person is coughing up blood or losing a lot of weight, says Dr. Tanner Caverly, a research investigator at the VA Center for Clinical Management Research in Ann Arbor, Michigan, which combines the expertise of clinicians and scientists from the VA Ann Arbor Healthcare System and the University of Michigan. By that point, the lung cancer is usually advanced — in the later stages when there’s much less chance treatment like surgery, chemotherapy or radiation will be effective, experts say — so the outlook is typically bleak.
“Overall the five-year survival in lung cancer, if you go back 40-plus years ago, maybe it was 10 percent of people lived five years, and now the most recent statistics, it’s maybe 18 percent live five years,” says Dr. Lee Kamman, co-chair of thoracic oncology program at Allina Health, and the medical director the Virginia Piper Cancer Institute at United Hospital in St. Paul, Minnesota. “So you’re still looking at a really, really bad prognosis.”
More recently, however, lung cancer screening is being used, though still to a fairly limited degree, to detect the No. 1 cancer killer in the U.S. earlier before a person has symptoms. Research has found screening with low-dose computed tomography, or CT, can reduce the rate of death from lung cancer in current or former heavy smokers by 20 percent, compared with chest X-ray, which isn’t considered a reliable way to screen for lung cancer. The U.S. Preventive Services Task Force currently recommends annual screening for lung cancer with LDCT in adults ages 55 to 80 who have smoked a pack a day for 30 years or more and currently smoke or have quit within the past 15 years. The independent expert panel suggests, “Screening should be discontinued once a person has not smoked for 15 years or develops a health problem that substantially limits life expectancy or the ability or willingness to have curative lung surgery.”
[See: 7 Things You Didn’t Know About Lung Cancer.]
Still, debate rages about who should be screened — whether the guidelines are inclusive enough — or even if the group recommended for screening should be smaller. In addition, it’s not only suggested but required by the Centers for Medicare & Medicaid Services that health providers have a detailed shared decision-making discussion with the patient, including talking over the risks of screening, in advance.
A primary concern is false positives, when the same CT technology that’s able to detect small nodules that could be cancer finds an abnormality that’s benign and will never cause the person harm. “If that finding isn’t framed appropriately for the patient, they can for a period of six months to a year be concerned about a cancer diagnosis that actually is nothing,” Caverly says. In the case of a false positive, most of the time a follow-up CT scan reveals the nodule isn’t growing, and it’s not a threat. But each scan also means radiation exposure, though less with LDCT than with a standard-dose CT. In some cases, though , more invasive procedures can follow.
Even a biopsy to take a small piece of the lung to look at it under the microscope to see if it’s cancer can be dicey. “Those biopsies actually have significant risks: collapsed lungs, bleeding, infection,” Caverly says. Patients who are candidates for lung cancer screening tend to be older people, and many have issues like chronic obstructive pulmonary disease, or COPD. They have “basically less than perfectly healthy lungs,” Caverly says. “And when you biopsy older people with less than perfectly healthy lungs, your risks do go up.”
To reduce the false positive rate, the American College of Radiology developed its Lung CT Screening Reporting and Data System, which raised the cutoff for benign nodules to six millimeters in diameter. That’s up from the four millimeter threshold used in the landmark National Lung Cancer Screening Trial, which showed the benefit of screening in reduced death but also had a high false-positive rate — since many of the small nodules weren’t cancer — that experts say has contributed to slow adoption of lung cancer screening. ACR’s widely adopted Lung-RADS quality assurance tool is “a way to have a very structured reporting — so there isn’t any ambiguous language with the actual reading of the CT scans,” says Dr. Michael Hanley, a thoracic radiologist and director of the lung cancer screening program at the University of Virginia Medical Center. “You still pretty much pick up all the cancers, but you decrease the false-positive rate from 27 percent to 10 percent without sacrificing sensitivity.”
[See: What Not to Say to Someone With Lung Cancer.]
Even so, significant risks remain, while at the same time only a fraction of those who are candidates for lung cancer screening don’t have it done. The downside of having an intensive program to not only talk patients through screening but to ensure results are interpreted appropriately is that it’s been a barrier to many more health providers offering lung cancer screening. “There’s a large regulatory burden which comes with a compliant program, and I think that has resulted in very, very few patients actually being seen and screened,” Hanley says. He says that, as a large academic medical center, UVA is able to meet requirements, and it’s trying to help smaller community-based health providers that don’t have same level of staffing to dedicate to lung cancer screening get their own programs off the ground.
The benefit-versus-risk calculation differs for each patient, making it important to tailor the conversation to the patient, according to Caverly. He recently led research published in the Annals of Internal Medicine seeking to help clinicians tailor the discussion to the patient, keeping in mind patient preferences and the benefit to a particular patient. “We found that the health gains of LDCT lung cancer screening vary considerably across the eligible population, with three factors being highly influential: risk for lung cancer, competing risks or life expectancy, and patient preferences,” the researchers note. How old a person is, or how long they are expected to live, can affect recommendations and decisions on cancer screening, including for lung cancer.
Health providers and researchers take into account a concept called the number needed to screen. Like the number needed to treat before one patient benefits, this considers the number of people who need to be screened for lung cancer, for one life to be saved. “The interesting thing about lung cancer screening is that mortality benefit really can differ based on someone’s lung cancer risk, which is a function of their age and smoking history,” Caverly says. “So there’s this huge range:” from one life saved for more than 500 of the lowest risk screening candidates who undergo LDCT, to 1 life saved for less than 100 of the highest risk candidates screened. The researchers found similar variation in using their simulation model to look at so-called quality-adjusted life years a person might gain from screening — to gauge not only how much longer a person would live, but take quality of life into consideration as well.
But with all the evaluation that’s gone into who is a candidate for screening, plus programs already in place to talk things through with patients and interpret results, Hanley says the research unnecessarily runs the risk of further narrowing the group that’s screened, from what the USPSTF recommends.
In an accompanying editorial published in the Annals of Internal Medicine, Dr. Michael K. Gould of Kaiser Permanente Southern California in Pasadena, California, defends the utility of the study, writing that the researchers “ask a provocative question through a novel lens: For patients who meet current U.S. Preventive Services Task Force eligibility criteria for lung cancer screening with LDCT, when is screening preference-sensitive and when should it just be done?” Not that patient-provider discussion shouldn’t happen, but when the potential for benefit is lower, risks are often a bigger consideration; whereas when the number of people who need to be screened for one life to be saved is lower — and the possibility for benefit higher — patients are going to be much more motivated to do just that, clinicians say.
[See: 10 Innovations in Cancer Therapy.]
A key takeaway, experts say, is that patients who are candidates for screening need to have that option available to them — so that they can have an informed discussion about that upfront, and possibly avoid having to react to a late-stage cancer diagnosis.
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Should You Get Screened for Lung Cancer? originally appeared on usnews.com
