Effect of Accurate Staging Using Positron Emission Tomography on the Outcomes of Prophylactic Cranial Irradiation in Patients With Limited Stage Small-Cell Lung Cancer.

BACKGROUND: Prophylactic cranial irradiation (PCI) was reported to offer survival benefits in patients with limited stage small-cell lung cancer (LS-SCLC). However, earlier studies did not routinely use positron emission tomography (PET) as part of the initial evaluation, thereby reducing the accuracy of tumor staging. We examined the effect of more accurate staging with PET on the role of PCI in patients with LS-SCLC.

PATIENTS AND METHODS: We retrospectively collected data from 280 patients with LS-SCLC who had objective responses after combined chemoradiotherapy between 2001 and 2013. The outcomes of PCI were analyzed after stratifying the patients according to whether or not the initial staging included PET imaging.

RESULTS: The risk of brain metastasis as the first site of relapse was lower in patients who received PCI than in those who did not, only in patients without initial PET imaging (13.3% vs. 37.0%; P = .020), but not in patients with initial PET imaging (34.3% vs. 41.1%; P = .243). There was no survival difference between subgroups who received PCI or not (5-year survival rates, 34.8% vs. 34.1%; P = .938). Patients who had initial staging evaluation with PET achieved long-term survival even without PCI (5-year survival rates, 38.3% with PCI, 38.6% without PCI).

CONCLUSION: The role of PCI needs to be critically reassessed in LS-SCLC patients whose initial staging evaluation included PET because the benefit of PCI was not apparent for them.