An analysis of patterns of care in the USA showed high adherence to guidelines; 98% of radiation oncologists recommended prophylactic cranial irradiation for patients with extensive-stage small-cell lung cancer with response to systemic chemotherapy.10 Are there other explanations for the absence of a survival benefit in the Japanese study? Interestingly, in the EORTC study, the opposite was observed, and the more frequent use of second-line or third-line chemotherapy after prophylactic cranial irradiation might have contributed to the survival benefit.2 Although side-effects that could be caused by chemotherapy were more frequent and severe in the prophylactic cranial irradiation group of the Japanese study, grade 3 or higher toxicity was rarely observed.3 In the EORTC study, temporary effects of prophylactic cranial irradiation on hair loss and fatigue were seen, but not on global quality of life.11 The investigators of the Japanese study have to be complimented for assessing cognitive functioning; no significant differences between groups were seen, possibly because of the small number of patients analysed. PCI Overview Collaborative Group, N Engl J Med, Vol. 341, 1999, 476-484 2 BJ Slotman, C Faivre-Finn, G Kramer, Prophylactic cranial irradiation in extensive small-cell lung cancer, N Engl J Med, Vol. 357, 2007, 664-672 3...