Prognostic Value of Preradiotherapy 18 F-FDG PET/CT Volumetrics in Limited-Stage Small-Cell Lung Cancer

Abstract Background Whether 18 F-fludeoxyglucose positron emission tomography (PET)/computed tomography (CT) metrics predict outcome in limited-stage (LS) small-cell lung cancer (SCLC) has not been well established; most previous reports have only analyzed maximal standardized uptake values (SUV max ). We investigated multiple pretreatment PET metrics, including SUV max , mean SUV (SUV mean ), total lesion glycolysis, and metabolic tumor volume (MTV) in LS-SCLC patients undergoing chemoradiotherapy (CRT) and correlated them with survival and disease control outcomes. Patients and Methods All patients received platinum-based chemotherapy and a median radiation dose of 45 Gy. Kaplan-Meier and competing-risks analyses were performed to assess the prognostic value of PET metrics with respect to overall survival (OS), distant failure (DF), disease-free survival (DFS), and locoregional failure (LRF). Univariate and multivariate analyses were performed to account for the effect of other clinical factors on outcomes. Results A total of 120 patients with LS-SCLC had analyzable pre-CRT PET/CTs. The median follow up was 34 months. Median OS was 26.9 months. OS was 53.2% at 2 years and 33.1% at 5 years. SUV max , SUV mean , MTV, and total lesion glycolysis of the primary tumor were not significantly associated with OS, LRF, and DFS on univariate analysis. MTV was significantly associated with DF ( P  = .024) on univariate but not multivariate analysis. Conclusion This is the largest reported series to date evaluating the prognostic value of baseline PET metrics in LS-SCLC. Neither SUV max nor other analyzed PET metrics demonstrated significant correlation with OS or LRF. MTV was correlated with DF and DFS, but this association was no longer significant after adjustment for other clinical factors. This analysis suggests that pretreatment PET scans, even with the use of advanced metrics, do not have independent prognostic value for outcomes in LS-SCLC patients after CRT.