Prophylactic brain irradiation: still an open question (review)

Prophylactic cranial irradiation (PCI) is still an open question despite the fact that ten randomized trials have been published in the past, addressing its impact on overall survival, disease-free survival and incidence of brain recurrences. The majority of these trials allow us to conclude that PCI is only useful in reducing the rate of brain recurrences, without any impact on survival. Nevertheless, there are some isolated monoinstitutional papers indicating a positive impact on survival. As all the published trials vary in the schedule and timing of cranial irradiation, patient selection and systemic treatment, all these factors can explain the impossibility of demonstrating survival effects in individual studies and the difficulty of collecting homogeneous data from their overview. However, even the limited benefit of a reduction in the rate of CNS relapses, shown by most of these studies, appears important due to the poor symptom relief and quality of life of the patients treated for clinically evident brain metastases. The occurrence of late CNS toxicity in prophylactically irradiated patients may hamper a clinical advantage in these individuals.