Reexamining the Ecology of Medical Care.

n engl j med 374;5 nejm.org February 4, 2016 495 volving this pathway has great promise in the treatment of stage IV Merkel-cell carcinoma. However, the interpretation of this case requires some consideration. The authors do not mention radiation therapy as a possible confounder in the spectacular response. Indeed, the patient received hypofractionated radiation to the liver shortly before treatment with idelalisib was initiated. Given the high response rates afforded with the use of single-fraction radiation therapy among patients with metastatic Merkel-cell carcinoma,3 we would caution against concluding that idelalisib alone was responsible for the complete remission observed in this case.