This week, the American Academy of Family Physicians (AAFP) elected to not follow the lead of the more influential US Preventive Services Task Force (USPSTF), which previously reviewed the information on chest CT screening for high risk patients and recommended it, and said that there is insufficient evidence to support chest CT screening.
The specific arguments were that, when the evidence from the National Lung Screening Trial is combined with some other, less definitive studies, there wasn’t a clear enough signal of benefit to support chest CT screening, per Dr. Doug Campos-Outcalt, MD, MPA, the AAFP liaison to the USPSTF.
“People need to understand that their life expectancy could be extended by this, but on the other hand, their life expectancy could be shortened by it,” Dr. Campos-Outcalt said in a statement. “If they’re currently smoking, a better thing to do by far is to stop smoking.”
For all too many people with lung cancer or caring for someone with it, the concept that lung cancer may not be threatening may seem sacrilegious. It is, after all, by far the leading cause of cancer deaths in the US in both men and women, far ahead of both breast cancer and prostate cancer in its fatality rate, though breast cancers and prostate cancers are more commonly diagnosed in women and men respectively. Yes, lung cancer is far more deadly than those two cancers, but both breast and prostate cancer are diagnosed in tens of thousands of people who aren’t truly threatened by it. The world has been slow to recognize that lung cancer can also sometimes be minimally threatening, but it’s worth discussing that possibility. And it shouldn’t lead us to minimize the danger of lung cancer any more than we should become complacent about handling deadly snakes just because there are some that are are perfectly safe. In the real world, a far greater proportion of lung cancers than snakes are deadly, but the main idea is that we should consider each based on individual characteristics. It is absolutely possible to “over-treat” a lung cancer.
This issue became newsworthy because of a new article in JAMA Internal Medicine that did a very complex calculated analysis (i.e., I didn’t understand it) of the lung cancers detected in the National Lung Screening Trial (NLST) and concluded that 18.5% of the lung cancers detected by chest CT screening and 22.5% of non-small cell lung cancers represented an “overdiagnosis” — a cancer that was detected but that would not be clinically relevant (as the numbers reflect, this is rarely a concern for small cell lung cancer). For bronchioloalveolar carcinoma (BAC), which is often indolent (and especially likely when detected as a solitary lesion), up to nearly 80% of these lesions were potentially overdiagnosed cancer.
As someone who sees the clinical behavior of hundreds of cases of lung cancer ever year, I’m here to tell you that this seems about right. This doesn’t mean that I don’t believe in CT screening for lung cancer: the NLST trial showed a 20% improvement in lung cancer-specific survival, which to me illustrates that screening for lung cancer is valuable. But it’s also worth knowing two things:
1) Not all lung cancers are life threatening.
2) There is a real risk of overtreating some lung cancers, causing more harm than benefit by treating it.
The most pivotal study supporting the value of screening for lung cancer is the National Lung cancer Screening Trial (NLST), which revealed a 20% improvement in overall survival in patients with sufficiently high risk of lung cancer and who underwent an annual chest CT scans vs. chest x-ray over a three year period. This significant benefit was seen in patients who were sufficiently high risk for lung cancer — patients age 55-75 and with at least a 30 “pack-year” smoking history (the product of number of years smoking x average number of packs smoked per day).
But even after this survival benefit was seen,there has been plenty of controversy that followed. Screening chest CT scans detects not only some true, life threatening lung cancer but also many, many benign lung nodules in people who undergo these scans. News of such nodules often cause people cause tremendous anxiety, along with a need for additional imaging and often invasive procedures to clarify whether the detected nodules are more likely to represent a benign finding or a real cancer.
Some patients and many institutions favor extending the screening of high risk patients to those at significantly lower risk, such as those who are younger, have minimal smoking history, perhaps even a never-smoker with a family history. But there is a real danger that if screening is applied people at low risk of actually having lung cancer, it’s far more likely that any nodules detected will be benign but will still lead to all of the anxiety, extra scans, and sometimes invasive procedures… just not to lives saved from lung cancer.
Why do screening on people who are at lower risk? Many people are nervous about lung cancer, and some institutions that make money by doing scans and procedures may be more than happy to oblige them or even feed their fears. We need to be judicious about how to use CT screening for lung cancer in a way that can save the most lives but lead to a minimal amount of extra scans, unneeded biopsies, and profound anxiety.
What is remarkably instructive as we struggle with these issues is a a new analysis of the results from the NLST study that stratified eligible patients by level of risk, which demonstrates the real risks of lung cancer vs. “false positives” – cases where the nodules required action and probably caused anxiety, but it wasn’t cancer. The investigators looked at a wide range of relevant variables for risk of lung cancer (age, sex, years since quitting, pack-years of tobacco exposure, family history, etc.), then divided the participants into 5 quintiles (5 equally sized groups). As we would expect, major differences were noted in the efficacy and significance of an abnormal result depending on whether people eligible for the NLST were higher or lower on the risk spectrum. Continue reading
I just did a brief video for Swedish Medical Center on the issue of low dose CT screening for lung cancer, which has been proven to improve survival. Though Dr. Otis Brawley, Chief Medical Officer of the American Cancer Society, just wrote a book about the risk of over-diagnosis of cancer, the ACS has just officially endorsed lung cancer screening, recognizing its value.
The only problem is that it really isn’t being done. I discuss a bit on the resistance to screening here:
A post on About.com makes the case that screening the higher risk population of just those people 55-75 with a significant smoking history, as was done in the influential National Lung Cancer Screening Trial (NLST) published last year in the New England Journal of Medicine, would miss nearly 3 of 4 lung cancers even as this effort improves lung cancer survival by 20% in the screened population. This piece implies that broader screening across of a wider range of ages and smoking history would be appropriate in order to detect more lung cancer and improve outcomes. So let me make two points.
1) I am a proponent of lung cancer screening for an appropriate population and think it’s underutilized now.
2) It is categorically incorrect to presume that broadening screening to a wider population will lead to better outcomes.
This is the third and final part of Dr. Weiss’s presentation on “Highlights in Lung Cancer, 2011″. After focusing on developments in relatively narrow subpopulations with distinct molecular markers in the first two parts of his webinar, Dr. Weiss closed with his coverage of a couple of issues with broader applicability: the new data supporting CT screening for higher risk people with a significant smoking history, and also some new data addressing the question of whether elderly patients are best served by receiving single agent or doublet chemotherapy.
Below you’ll find the podcast of the program in audio and video formats, as well as the transcript and figures for this activity.
This long-overdue podcast by Dr. Mark Millard, Medical Director of the Baylor Martha Foster Lung Care Center and Professor of Pulmonology at Baylor University in Dallas, TX, focuses on many aspects of smoking cessation: how physicians can effectively discuss it with patients, how anyone can discuss the issue constructively with a smoker, and how someone motivated to quit can use a wide range of tools — both behavioral and medical — to optimize their chance of quitting for good.
Here are the audio and video versions of the podcast, along with the transcript and figures for the program.
The National Lung Screening Trial (NLST), a protocol with over 50,000 former or current smokers between ages 55 and 75, justifiably became a major news story when the results demonstrated a significant improvement in lung cancer-specific and all-cause mortality of 20% and 6.7%, respectively. However, now even a year after the initial press releases about the positive results and several months after its publication in the New England Journal of Medicine (marking it as a practice-changing finding), CT screening for lung cancer hasn’t yet become routine practice. Why not? In contrast with screening results in breast or colon cancer, where positive results have led to a change in policy, the cost of implementing a broad screening policy today entails a public debate about the feasibility, which largely centers around costs.
In this context, a paper by McMahon and colleagues in the Journal of Thoracic Oncology provides a valuable analysis. The authors created a data-based simulation of cohorts of men and women of ages 50, 60, and 70 (six distinct cohorts) with a significant smoking history that would reflect the range of patients included in a screening program instituted based on the NLST. Calculating results based on the data from this simulation, they then analyzed the cost-effectiveness in the common term for this measurement of “costs per quality-adjusted life-year gained ($/QALY)” (essentially, how much does it cost to improve one person’s life by a year of functional, “good” time?) for these cohorts when modeling estimated outcomes for CT screening, smoking cessation interventions (with a range of abstinence ranging from 4 to 30% at one year), and a combination of these two approaches.
The much-anticipated manuscript from the NCI-sponsored National Lung Screening Trial (NLST) was just published on line in the New England Journal of Medicine, with an editorial by Dr. Harold Sox. As Dr. West outlined in a previous post, we’ve known since last year that this trial demonstrated an improvement in lung-cancer specific survival with low-dose spiral CT screening of high-risk individuals. However, we have not had access to the details of this study until now. One of the fundamental problems we face is that lung cancer is most often diagnosed in an advanced stage. This has generated intense interest in screening and early detection. However until this trial, no screening test has been shown to reduce the risk from dying from lung cancer, which is the benchmark we use to judge the effectiveness of any screening modality. As the first trial that shows lung cancer screening can save lives, the NLST will no doubt have a significant impact on how we practice in this country and should be viewed as a very hopeful result for lung cancer advocates. However, many questions remain and as is the case with any medical intervention, individuals considering low dose CT screening will need to weigh not only the potential benefit (as defined for the first time by this trial), but also the potential risks associated with this approach. The NLST will go a long way towards informing this decision.
For years and years, lung cancer advocates have often aggressively championed screening for lung cancer, while many in the medical “establishment” and policy-makers expressed reservations that, while there were encouraging indicators of benefit, there was not evidence that lung cancer screening saves lives, so we really couldn’t make a blanket statement encouraging lung cancer screening. That has now changed, as the NCI-sponsored National Lung Screening Trial (NLST) has now been reported to demonstrate a 20% improvement in lung cancer-specific survival. A preliminary but detailed manuscript describing the trial itself is published in the journal Radiology and is available at no charge.
The trial was started in 2002 and randomized over 53,000 patients who were 55-75 and had at least a 30 pack-year smoking history (pack-years being the product of average number of packs of cigarettes smoked per day x number of years smoking) to either annual low-dose spiral CT scans for three consecutive years or a chest x-ray on the same interval. These screening CT scans are done without IV contrast and are done within a single breath hold (up to 15 seconds) but can fully view the lung fields.
The Data Safety Monitoring Committee that regualrly reviews the trial results over the course of a study’s ongoing conduct recently reviewed the most current results and noted a statistically significant improvement in the lung cancer-specific survival of people were were randomized to screening CT scans. Specifically, there were 354 deaths from lung cancer on the CT arm, vs. 442 deaths from lung cancer on the arm assigned to chest x-rays, a 20.3% reduction. In addition, the CT screened patients had a 7% reduction in “all cause mortality” (not just lung cancer, but deaths for any reason), with only 25% of the deaths in the overall trial due to lung cancer. This was likely due to detection of issues such as cardiovascular disease and other incidental but significant medical problems with CT but not chest x-ray screening.