Brain metastases are common in patients with limited-stage small cell lung cancer (LS-SCLC) due to the inability of most chemotherapeutics to penetrate the blood-brain barrier. Prophylactic cranial irradiation (PCI) is therefore recommended for use in patients with a good response to concurrent chemoradiotherapy. However, PCI is not always delivered; therefore, we investigated the reasons for PCI omission in patients who underwent therapy with curative intent.

We retrospectively reviewed all patients with LS-SCLC who were treated with curative intent at our institution. Overall survival and cumulative incidence of brain metastasis were estimated by the Kaplan-Meier method. The Pearson χ test and Mann-Whitney U test were used to examine factors associated with PCI use, and prognostic factors were analyzed with Cox proportional hazards modeling.

We examined 208 patients who were treated for LS-SCLC at our institution. A total of 115 patients (55%) received PCI. The most common documented reason for PCI omission was patient refusal due to neurotoxicity concerns (38%). Physician assessment of being medically unfit (33%) and of advanced age (8%) were the second and third most common reasons, respectively. Karnofsky performance status and clinical American Joint Committee on Cancer stage but not PCI were significantly associated with overall survival. Only clinical stage remained an independent factor on multivariate analysis.

Approximately half of patients with LS-SCLC ultimately receive PCI, generally for guideline-recommended reasons. The most common reason for PCI omission was patient concerns regarding neurotoxicity. Efforts to decrease PCI neurotoxicity, including hippocampal-sparing radiation and memantine use, may increase the use of this survival-improving intervention in eligible patients with LS-SCLC.