Quantitative assessment of the asphericity of pretherapeutic FDG uptake as an independent predictor of outcome in NSCLC

Abstract

BackgroundThe aim of the present study was to evaluate the predictive value of a novel quantitative measure for the spatial heterogeneity of FDG uptake, the asphericity (ASP) in patients with non-small cell lung cancer (NSCLC).MethodsFDG-PET/CT had been performed in 60 patients (15 women, 45 men; median age, 65.5 years) with newly diagnosed NSCLC prior to therapy. The FDG-PET image of the primary tumor was segmented using the ROVER 3D segmentation tool based on thresholding at the volume-reproducing intensity threshold after subtraction of local background. ASP was defined as the relative deviation of the tumor’s shape from a sphere. Univariate and multivariate Cox regression as well as Kaplan-Meier (KM) analysis and log-rank test with respect to overall (OAS) and progression-free survival (PFS) were performed for clinical variables, SUVmax/mean, metabolically active tumor volume (MTV), total lesion glycolysis (TLG), ASP and “solidity”, another measure of shape irregularity.ResultsASP, solidity and “primary surgical treatment” were significant independent predictors of PFS in multivariate Cox regression with binarized parameters (HR, 3.66; p < 0.001, HR, 2.11; p = 0.05 and HR, 2.09; p = 0.05), ASP and “primary surgical treatment” of OAS (HR, 3.19; p = 0.02 and HR, 3.78; p = 0.01, respectively). None of the other semi-quantitative PET parameters showed significant predictive value with respect to OAS or PFS. Kaplan-Meier analysis revealed a probability of 2-year PFS of 52% in patients with low ASP compared to 12% in patients with high ASP (p < 0.001). Furthermore, it showed a higher OAS rate in the case of low versus high ASP (1-year-OAS, 91% vs. 67%: p = 0.02).ConclusionsThe novel parameter asphericity of pretherapeutic FDG uptake seems to provide better prognostic value for PFS and OAS in NCSLC compared to SUV, metabolic tumor volume, total lesion glycolysis and solidity.

PET Radiomics in NSCLC: state of the art and a proposal for harmonization of methodology

“…Concerning overall survival, only “asphericity” and “primary surgical treatment” (p = 0.02 and = 0.01, respectively) proved to be independent predictors, and none of the other PET parameters (including SUV max , TLG, and MTV) showed a significant predictive value in this series of patients 73 .…”

“…Compared with Adk, Sqc is characterized by higher SUV max , AUC-IVH, energy GLMC , entropy GLCM , sum entropy, difference entropy, and inverse different moment and by lower homogeneity GLCM , sum of squares, angular second moment, ratio of non-zero Gr , and difference variance 60–62 . Prognostic and predictive role Heterogeneity (i.e., AUC-CSH) can predict recurrence in pN0 Adk patients who have undergone curative surgery but not in Sqk patients (high heterogeneity is associated with a shorter DFS) 61 .Best prognostic value for overall survival is found for relative portions of the tumor above higher uptakes defined as SUV max  > 80% (i.e., V 80 ) in patients who received radiation therapy (sequential chemoradiation, concurrent chemoradiation, or only radiation). The higher the portion above higher uptake (V 80 ), the better the prognosis 29, 80 .Heterogeneity (i.e., low AUC-CSH) identifies patients with inoperable stage III NSCLC with poor PFS 75 .High SUV max , large MTV, and high heterogeneity (i.e., high entropy GLCM , high asphericity, homogeneity GLCM , and high dissimilarity, size-zone variability, and low zone percentage) are associated with poorer OS and RFS in stage I–III NSCLC 35, 73, 74, 83 .Tumor heterogeneity (i.e., entropy GLCM ) is associated with response to radiation therapy in NSCLC (DSS is lower for patients with high entropy GLCM ) 79 .Lesions in responders (complete or partial response) to chemoradiotherapy are characterized by lower coarseness, contrast NGTDM , and busyness than non-responders (stable or progressive disease). High coarseness values are associated with an increased risk of progression (increased risk of death), whereas high contrast NGTDM and busyness values are associated with a lower risk of progression (PFS and LPFS) 14 .Large primary tumors with low SumAverage (i.e., more heterogeneous) have a poor prognosis following chemoradiotherapy 76 .Lesions in responders to erlotinib are characterized by lower heterogeneity than those in non-responders.…”

Mental speed is associated with the shape irregularity of white matter MRI hyperintensity load

“…In medicine it has been used to define the “asphericity” of the metabolically active part of a tumor in whole body positron emission tomography with the glucose analog F-18-fluorodeoxyglucose (Apostolova et al 2014a; Apostolova et al 2014b; Hofheinz et al 2014). …”

Nouveaux indices en TEP/TDM : mythe et réalités

“…Leur valeur pronostique s'est avérée supérieure à celles des indices standards [24]. Enfin, la valeur pronostique dans le cancer ORL [25,26] et du poumon [27] d'un paramètre de forme appelé asphéricité, qui quantifie l'écart à une sphère parfaite de la surface du volume segmenté, a été récemment démontrée. Un point fort de ces derniers travaux est l'analyse statistique multivariée rigoureuse réalisée sur un nombre suffisant de patients, qui a permis de montrer sa valeur pronostique indépendante par rapport au volume segmenté et autres indices standards, ainsi qu'aux variables cliniques usuelles.…”

“…. ), avec des exemples dans les cancers de la sphère ORL [25,26,53], le cancer du poumon [19,27,31,35] ou encore les sarcomes [23].…”