Measuring response to treatment in lung cancer

In honor of November being pancreas and lung cancer awareness month, I bring you some interesting studies for lung cancers today and another entry to follow that will focus on pancreas adenocarcinoma. (Yes, you read right: The month with the shortest days and the beginning of a long winter also marks the month for two of our hardest-to-treat cancers. Coincidence?)

For lung cancer, I came across this interesting article by Crabb et al, from early 2009 in the Journal of Clinical Oncology where the researchers argue that for non–small cell lung cancer studies with vascular endothelial growth factor receptor (VEGF) inhibitors, cavitation of the tumor should be included in measurement of response, beyond the usual RECIST criteria. This is because tumors will frequently cavitate out in the middle but retain the same longest dimension measurement, thus looking like stable disease by our usual measurements.

The authors further advocate for calling it progression when the cavitation fills in, which is usually sooner than when the patient's tumor would meet the RECIST criteria for progressive disease. The authors found that when they looked at those who cavitated (all of whom were on VEGF inhibitors), they found 33% of patients met this cavitation criteria. There was not as big of a benefit in terms of earlier response or time to progression, however, but this was a small study and really shouldn't be the gold standard.

I think it is novel to think of the drugs used when considering how response should be evaluated, and while I don't think measurement of cavitation is ready for prime time, it is quite interesting and should be looked at prospectively because anecdotally I think there may actually be something to it.