Is It Premature to Utter the Word 'Cure' in Advanced Lung Cancer?

One of the core tenets in medicine is that there's no always or never. In fact, I spent much of the past two decades explaining to patients in my thoracic oncology clinic that stage IV lung cancer isn't curable, but it is treatable. This cancer would come back even after our most promising responses in this setting.

Somewhere in the past few decades, however, the foundation of what I knew has shifted radically. Patients with metastatic lung cancer typically used to live for months; now, with immunotherapies, targeted therapies, and lower-risk local therapies, we expect more and more of these patients to live for years.

So I suppose I shouldn't be surprised that oncologists may now find themselves debating whether metastatic lung cancer is still a categorically incurable disease.

Outcomes in some patients with advanced lung cancer are defying our expectations. And now that patients are shattering 5-year survival barriers, I would argue that we should consider a subset of patients with metastatic non–small cell lung cancer (NSCLC) effectively cured.

And yet, I see remarkably little discussion of this question in professional meetings, journal articles, or conversations among colleagues in the clinic. Why are we reluctant to consider that some patients with advanced cancer might be considered cured?

One concern is that prolonged responses, even extended intervals with no evidence of disease, should not be presumed to signal that the cancer won't relapse. My patients with NSCLC with a driver mutation now routinely achieve a median survival of several years and occasionally 4 to 5 years with no evidence of disease. Yet we know that the vast majority will eventually develop acquired resistance that makes their cancer harder to treat. We also know that if we were to stop targeted therapy, nearly all of these patients would progress within weeks to months. In addition, many of us have patients who experience a late relapse.

But I have a few patients with metastatic lung cancer who have had no evidence of disease longer than I would have ever thought feasible. Some of these patients remain off treatment for years, without a hint that their cancer will return. Given this, we should at least consider that these patients may be cured.

I asked my colleagues on Twitter for their thoughts: Do you think we can realistically expect some patients with stage IV lung cancer to be "cured"? What I found was that almost half of 400 respondents felt that some of these patients are truly cured. However, among this group, only about 20% felt confident sharing that sentiment with patients. The other 30% did not. Among the remaining respondents, about 30% felt that the survival results were tremendous but didn't represent a cure — suggesting that they anticipate a relapse, even if well outside the previously expected timeline — and 20% felt that they still needed additional years of follow-up with these patients.

I also received several thoughtful comments from respondents, a few papers about how we should define "cure," and a reluctance among many cancer care professionals to invoke the term, even for patients who are still alive a decade or more after their diagnosis. Perhaps some who are disinclined to say "cure" feel that the concept should not be accompanied by qualifications — that it requires a level of certainty we can't offer. And overall, I appreciate not wanting to overpromise or offer patients false hope, and I recognize that prematurely declaring someone cured only to have their cancer relapse can be emotionally devastating.

But we know that the immune system can work to perpetually control disease long after treatment ends, so we are not being disingenuous when we convey the hope that a patient's life may not be cut short by cancer. To me, that is a fair definition of cure, even if there is a calculable but exceptionally low risk for relapse in a patient with no sign of disease a decade out. I acknowledge that we don't have longitudinal data to say anything definitive, but I find myself in the unusual position of being the optimist, of wanting to offer patients hope while also sharing this uncertainty.

One of my longtime friends and colleagues, a thoracic surgeon, plants the seed during his initial workup: He hopes to have his patients reach a 5-year milestone of survival, marked by bringing in a cake at that follow-up visit. While some may not reach that 5-year mark, I think focusing on the positive is a welcome opportunity, even in the absence of absolute certainty.

And if this approach also provides a few cakes, so much the better.

What are your thoughts about invoking the word "cure" in certain circumstances?

H. Jack West, MD, associate clinical professor and executive director of employer services at City of Hope Comprehensive Cancer Center in Duarte, California, regularly comments on lung cancer for Medscape. Dr West serves as web editor for JAMA Oncology, edits and writes several sections on lung cancer for UpToDate, and leads a wide range of continuing education programs and other educational programs, including hosting the audio podcast West Wind.

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