According to an article in the Boston Globe, a federal class action lawsuit filed in Boston last week on behalf of all 50+ year-old smokers in Massachusetts who have smoked at least one pack per day of Marlboro cigarettes for at least 20 years seeks to force Philip Morris - the manufacturer of Marlboro - to pay for low-dose chest CT scans for this class of smokers in order to attempt to diagnose lung cancer at an early stage and therefore save lives.
According to the article: "Low-dose, noninvasive CT scans cost about $500, but they are rarely covered by health insurance. The complaint, filed in US District Court, requests that Philip Morris fund CT scans for people at least 50 years old who have smoked a pack of Marlboro cigarettes a day for at least 20 years -- the equivalent of at least 146,000 cigarettes -- and have not been diagnosed with lung cancer. It does not demand monetary damages. ... as many as 80,000 Massachusetts residents could become part of the class, an estimate based on public health data and Philip Morris's market share."
The lawsuit follows by about six weeks the publication of an article in the New England Journal of Medicine which reports that in a large multi-center, collaborative study of the use of low-dose CT scans for early detection of lung cancer (International Early Lung Cancer Action Program - ELCAP) among 27,456 high-risk patients, 85% of lung cancers detected were in the earliest stage (stage I) and the 10-year survival of these patients was 88%. The article concludes that "Annual spiral CT screening can detect lung cancer that is curable."
Without screening for lung cancer (when lung cancer is detected only when patients present with symptoms), the overwhelming majority of cases are detected in later stages (stages II and higher), which have a dismal prognosis. The stage I cancers have the best prognosis and are the only ones which are felt to have any substantial chance of being cured. By shifting the proportion of diagnosed lung cancers heavily towards stage I, it is thought that spiral CT scanning might result in earlier detection and treatment of tumors and therefore save lives.
The lawsuit apparently contends that Philip Morris produced a cigarette with many carcinogens in it that didn't have to be in there, that a safer alternative product was available but rejected by the company, and that because smokers in Massachusetts are at risk of lung cancer due to the presence of these carcinogens, Philip Morris ought to provide this screening procedure that could save the lives of many of these smokers.
The Rest of the Story
While this all may sound compelling, there is a rest of the story.
First of all, without a control group, the ELCAP study results do not necessarily prove that CT screening for lung cancer reduces mortality and saves lives. There are two potential biases that could be operating, which cannot really be evaluated in the absence of a control group.
Lead time bias is when screening detects cancer at an earlier time than it otherwise would have been diagnosed, but does not change the survival. It is possible that the survival of patients in the study was not altered - what was altered was merely the time of their diagnosis.
Overdiagnosis refers to the detection of indolent cancers that are slow-growing and unlikely to cause death.
Without a control group, it is difficult to assess whether or not the reported results are subject to lead time bias or to overdiagnosis, and therefore, it is difficult to conclude definitively that this screening procedure saves lives. A clinical trial is now underway in which patients are being randomized to either receive spiral CT screening or a conventional chest X-ray. This clinical trial will help to determine whether CT screening can indeed save lives. But until those results are in, it seems premature to be forcing Philip Morris to provide a screening program that has not yet been documented to save lives.
Another major problem is that spiral CT screening for lung cancer has not yet been shown to be an effective and appropriate screening tool. The specificity of the test is very low, and combined with a very low prevalence of lung cancer in the population, the positive predictive value of CT screening is dismally low. This means that the overwhelming majority of patients who have lung nodules detected on CT scan will not have lung cancer. But these patients will require follow-up monitoring, and some will even require further invasive procedures to obtain a definitive diagnosis. These procedures carry a morbidity and even a mortality risk themselves and a number of the diagnostic procedures will result in morbidity or possibly mortality unnecessarily (by which I mean morbidity or mortality in patients who do not have lung cancer).
Another important consideration is the anxiety that could be produced in a huge number of patients who have nodules detected on CT scan but who do not have lung cancer. The protocol calls on these patients to either have invasive diagnostic procedures, which can be physically damaging, or to simply wait for 3 months for a follow-up test, which can be psychologically damaging. Imagine the anxiety a patient would have if told that they have an abnormal nodule in their lung that could be cancerous and what the doctor wants them to do is sit around for 3 months and try not to think about it.
I don't know about you, but I'd be unable to do that without severe anxiety and severe interference with my ability to function. I'd want a definitive diagnosis right away. As a physician, I would feel very uncomfortable telling my patient: "We detected an abnormal nodule in your lung that is somewhat suspicious for lung cancer. We're not sure. Why don't you make a follow-up appointment for 3 months from now and we'll see how it's progressing. See you in a 3 months. Have a good one."
In the ELCAP study, 4186 patients were identified as having abnormal lung nodules at baseline CT screening. Of these patients, only 405 were found to have lung cancer. Thus, 3781 patients had false positive results. The positive predictive value of the test was therefore only 10%. This means that a positive test result (the finding of a lung nodule) only indicates lung cancer 10% of the time. Ninety percent of the time, the test is wrong. That's usually viewed as being unacceptable for a screening test.
In this case, having 90% of your patients with nodules worrying unnecessarily for 3 months hardly seems acceptable to me.
If there were some gold standard, definitive test that could be performed immediately following the baseline CT scan to determine whether or not a patient has lung cancer, then this initial screening test might be acceptable. But I find it quite troubling that patients are being told that they may have cancer - please come back in 3 months and we'll either tell you how much it's grown or we'll tell you never mind, false alarm.
Also concerning is the fact that in this study, 43 patients had some form of invasive or surgical procedure, presumably ranging from fine-needle aspiration to bronchoscopy to mediastinoscopy to open lung biopsy, but ended up having nothing wrong with them. Based on the number of participants in ELCAP and the number of potential smokers in the proposed class, we would expect to have about 120 of the class members end up needing an invasive diagnostic procedure when there is nothing wrong. Among these 120 people, we would expect to have a non-negligible number wind up with significant morbidity -- all for no reason and with no benefit to them.
In other words, what I'm trying to say is that without a doubt, instituting such a screening procedure is guaranteed to cause harm to some patients. It is likely to cause psychological harm to many, and physical harm to a smaller, but not negligible number of class members.
On the other hand, we cannot say with certainty that instituting this screening procedure will result in benefit to any of the class members. It has simply not yet been demonstrated definitively that spiral CT screening for lung cancer does save lives.
I'm not sure how you can ask a court to force Philip Morris to pay for a procedure that is guaranteed to cause some harm, but not definitively guaranteed to have any benefit.
Don't get me wrong. I'm not saying that spiral CT screening for lung cancer will never be an effective and appropriate screening test or that it won't ultimately be shown to save lives or that the benefits of this screening will not end up outweighing the risks and costs. I'm just saying that based on the evidence that is available right now, I don't think one can make a reasonable determination that the proposed screening program will produce a net benefit to this class of smokers.