Long-term outcomes and failure patterns of prophylactic cranial irradiation in limited-stage small cell lung cancer patients managed with modern chemoradiotherapy and diagnostic methods / 中华放射肿瘤学杂志

ABSTRACT

Objective:To evaluate the clinical efficacy and failure patterns of prophylactic cranial irradiation (PCI) in patients with limited-stage small cell lung cancer (LS-SCLC) on the basis of modern chemoradiotherapy and diagnostic techniques.Methods:In this retrospective study, clinical data of 201 LS-SCLC patients treated with chemotherapy (EP/CE regimens, ≥4 cycles) and intensity-modulated radiotherapy (IMRT) in Cancer Hospital of Chinese Academy of Medical Sciences from 2006 to 2014 were reviewed. All patients were primarily managed with concurrent or sequential chemoradiotherapy and achieved complete response (CR) or partial response (PR). Ninety percent of patients were revaluated for brain metastasis (BM) by MRI and 10% by CT scan. Long-term survival and failure patterns were compared between the PCI ( n=91) and non-PCI groups ( n=110). Results:The median follow-up time was 77.3 months (95% CI 73.0-81.5 months). The median overall survival (OS), 2-and 5-year OS rates were 58.5 months, 72.5% and 47.7% in the PCI group, and 34.5 months, 61.7% and 35.8% in the non-PCI group ( P=0.075). The median progression-free survival (PFS), 2-and 5-year PFS rate were 22.0 months, 48.0% and 43.4% in the PCI group, significantly higher than 13.9 months, 34.4% and 26.7% in the non-PCI group ( P=0.002). The 2- and 5-year cumulative incidence of BM were 6.6% and 12.2% in the PCI group, and 30.0% , 31.0% in the non-PCI group ( P=0.001). The median time and rate of BM as an isolated first site of relapse were 11.9 months and 4.4% in the PCI group, and 8.7 months and 25.5% in the non-PCI group ( P<0.001). Multivariate analysis showed that response after chemoradiotherapy ( P<0.001) and PCI ( P=0.033) were the independent prognostic factors for PFS. Stratified analysis demonstrated that PCI significantly improved the 5-year PFS in patients who achieved CR (72.7% vs. 48.0%, P=0.013), while it did not improve the 5-year PFS in patients who obtained PR (26.1% vs. 20.2%, P=0.213). Conclusion:In the new era of standard chemoradiotherapy and more accurate diagnostic methods for BM, PCI was associated with improved PFS and lower incidence of BM in LS-SCLC patients.