Fluorodeoxyglucose positron-emission tomography ratio in non-small cell lung cancer patients treated with definitive radiotherapy

Abstract

PurposeTo determine whether the maximum standardized uptake value (SUV) of [18F] fluorodeoxyglucose uptake by positron emission tomography (FDG PET) ratio of lymph node to primary tumor (mSUVR) could be a prognostic factor for node positive non-small cell lung cancer (NSCLC) patients treated with definitive radiotherapy (RT).Materials and MethodsA total of 68 NSCLC T1-4, N1-3, M0 patients underwent FDG PET before RT. Optimal cutoff values of mSUVR were chosen based on overall survival (OS). Independent prognosticators were identified by Cox regression analysis.ResultsThe most significant cutoff value for mSUVR was 0.9 with respect to OS. Two-year OS was 17% for patients with mSUVR > 0.9 and 49% for those with mSUVR ≤ 0.9 (p = 0.01). In a multivariate analysis, including age, performance status, stage, use of chemotherapy, and mSUVR, only performance status (p = 0.05) and mSUVR > 0.9 (p = 0.05) were significant predictors of OS. Two-year OS for patients with both good performance (Eastern Cooperative Oncology Group [ECOG] ≤ 1) and mSUVR ≤ 0.9 was significantly better than that for patients with either poor performance (ECOG > 1) or mSUVR > 0.9, 23% (71% vs. 23%, p = 0.04).ConclusionOur results suggested that the mSUVR was a strong prognostic factor among patients with lymph node positive NSCLC following RT. Addition of mSUVR to performance status identifies a subgroup at highest risk for death after RT.