A Prospective Study of Hippocampal-Sparing Prophylactic Cranial Irradiation (PCI) in Limited-Stage Small Cell Lung Cancer (SCLC)

Abstract Objectives Neurocognitive toxicity may be related to hippocampal dose. This prospective study evaluated cognitive function and intra-cranial failure patterns following hippocampal-sparing PCI for limited stage SCLC. Methods Adults with limited stage SCLC, achieving a complete response to chemo-radiotherapy and no brain metastases were eligible. Patients received PCI 25 Gy/10 fractions with a mean hippocampal dose limited to Results Eight men and 12 women with a median age of 61 years enrolled. Two-year OS was 88% (95% CI, 68-100%). There was no significant decline in performance between baseline and 6- or 12- months for any of the tests. The association between baseline IQ and change in performance on testing was not significant. MRI revealed asymptomatic brain metastases at a cumulative rate of 20% with no concurrent extra-cranial progression. Two patients developed a metastasis in the under-dosed region. Neither involved the dentate gyrus, but 1 involved the avoidance region. Both patients concurrently developed additional metastasis in fully treated brain regions. There were 2 neurologic deaths. Conclusions This prospective study suggests a potential benefit of hippocampal-sparing in limiting the neuropsychological sequelae of brain radiation, but with a risk of failures in the spared region. These data strongly support continued enrollment on ongoing cooperative group randomized trials. Clinical Trials Registration Number: NCT01797159.