Purpose: Prophylactic cranial irradiation (PCI) can improve overall survival (OS) and suppress brain metastases (BM) in patients with limited-stage small cell lung cancer (LS-SCLC) after complete response to primary therapy. However, PCI can be toxic. We sought to identify characteristics of patients who may not benefit from PCI.
Methods: We identified 658 patients who received chemoradiotherapy at MD Anderson in 1986-2012; 364 received PCI and 294 did not. Median follow-up time was 21.2months (range 1.2-240.8months). Cox proportional hazards regression, competing-risk regression, and Kaplan-Meier analyses were used to identify factors influencing OS and BM.
Results: PCI reduced risks of death [HR 0.73, 95% CI 0.61-0.88, P=0.001] and BM [HR 0.54, 95% CI 0.39-0.76, P<0.001]. Having tumors ⩾5cm increased the risk of BM [HR 1.77, 95% CI 1.22-2.55, P=0.002] but not death [HR 1.16, 95% CI 0.96-1.40, P=0.114]. Among patients ⩾70years with ⩾5-cm tumors, PCI did not improve OS [2-year rates 39.4% vs 40.9%, P=0.739].
Conclusions: PCI remains standard therapy after complete response to chemoradiotherapy for LS-SCLC. However, older patients may be at risk from comorbidity or extracranial disease. Further work is warranted to identify patients who may not benefit from PCI.
Keywords: Chemoradiation; Elderly patients; Overall survival; Prognostic factors; Prophylactic cranial irradiation; Small cell lung cancer.
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