Over the past several years, oncologists have experienced an evolution in the way we think about stable disease, at least in the context of lung cancer. Historically, oncologists have graded our work by looking at response rates, or the percentage of patients with tumor shrinkage of 50% or more of their lesions as measured in two dimensions. We considered a drug or combination to be “active” if it had an “objective response rate” (ORR) of 15% or more, and we generally discarded approaches that had a lower ORR than that.

But largely as a response to the recognition that some targeted therapies may potentially halt tumor growth but not significantly shrink or kill a cancer, we’ve come to acknowledge that achieving stable disease can translate to a valuable clinical benefit for patients (as in, patients are likely to live signfiicantly longer). Of course, we all want to see tumors melt away, but at least in the setting of advanced lung cancer, having the cancer shrink just a little or just stay the same for several months at a time is a real improvement over the natural history of what the cancer would do, which is grow steadily over time. We also often see that patients who have chemo with or without radiation before surgery sometimes show no significant tumor shrinkage, but after surgery we find that the tumor contains mostly or only dead tumor cells. So again, stable disease underestimated clinical benefit of treatment. Continue reading →