Prognostic Value of Standardized Uptake Ratio in Patients with Trimodality Treatment of Locally Advanced Esophageal Carcinoma

Abstract

The prognosis of patients with esophageal carcinoma remains dismal despite ongoing efforts to improve treatment options. For locally advanced tumors, several randomized trials have shown the benefit of neoadjuvant chemoradiation followed by surgery compared to surgery alone. The aim of this exploratory study was to evaluate the prognostic value of different baseline positron emission tomography (PET) parameters and their potentially additional prognostic impact at the end of neoadjuvant radiochemotherapy. Furthermore, the standard uptake ratio (SUR) as a new parameter for quantification of tumor metabolism was compared to the conventional PET parameters metabolic active volume (MTV), total lesion glycolysis (TLG), and standardized uptake value (SUV) taking into account known basic parameters. F-FDG-PET/CT was performed in 76 consecutive patients ((60±10) years, 71 males) with newly diagnosed esophageal cancer before and during the last week of neoadjuvant radiochemotherapy. MTV of the primary tumor was delineated with an adaptive threshold method. The blood SUV was determined by manually delineating the aorta in the low dose CT. SUR values were computed as scan time corrected ratio of tumor SUV and mean blood SUV. Univariate Cox regression and Kaplan-Meier analysis with respect to locoregional control (LRC), freedom from distant metastases (FFDM), and overall survival (OS) was performed. Additionally, independence of PET parameters from standard clinical factors was analyzed with multivariate Cox regression. In multivariate analysis two parameters showed a significant correlation with all endpoints: restaging MTV and restaging SUR. Furthermore, restaging TLG was prognostic for LCR and FFDM. For all endpoints the largest effect size was found for restaging SUR. The only basic factors remaining significantin multivariate analyses were histology for OS and FFDM and age for LRC. PET provides independent prognostic information for OS, LRC, and FFDM in addition to standard clinical parameters in this patient cohort. Our results suggest that the prognostic value of tracer uptake can be improved when characterized by SUR rather than by SUV. Overall, our investigation revealed a higher prognostic value of restaging parameters compared to baseline PET; therapy-adjustments would still be possible at this point of time. Further investigations are required to confirm these hypothesis-generating results.

Prognostic Value of Lymph Node to Primary Tumor Standardized Uptake Value Ratio in Unresectable Esophageal Cancer

“…An important and fundamental question is that what is the additional benefits could be offered with NTR rather than SUV LN alone. An aspect is the adaptation of NTR plays the role of internal control like other ratio methods do, which may reduce the factors that affecting SUV quantitation, e.g., tracer dose and patient's weight uncertainties, acquisition time, and machine calibration (17). Another possible and reasonable hypothesis is that NTR reflects the different behaviors between tumors with higher and lower metastatic potential.…”

18F- FDG PET/CT-derived parameters predict clinical stage and prognosis of esophageal cancer.

“…cardiac output, tumor histology) but also to the PET/CT configuration and interobserver variability. To overcome these limitations, tumor-to-blood Standard Uptake Ratio (SUR) has been recently published as a promising predictor of survival [23,24]. Hofheinz et al [23] suggest the superiority of baseline SUR over SUVmax to predict overall survival in squamous cell cancer patients treated with definitive chemoradiation, whereas Bütof et al [24] propose the restaging SUR value along with baseline MTV as a reliable survival predictor.…”

“…To overcome these limitations, tumor-to-blood Standard Uptake Ratio (SUR) has been recently published as a promising predictor of survival [23,24]. Hofheinz et al [23] suggest the superiority of baseline SUR over SUVmax to predict overall survival in squamous cell cancer patients treated with definitive chemoradiation, whereas Bütof et al [24] propose the restaging SUR value along with baseline MTV as a reliable survival predictor. In a recent meta-analysis, Han et al reinforce the prognostic value of MTV and TLG for overall survival, although no specific cutoff value is suggested and both histological types are jointly taken into account [8].…”

Whole‐body parametric PET imaging will replace conventional image‐derived PET metrics in clinical oncology

“…Alterations in blood pool activity is indeed one of the main sources of variability for which the application of whole‐body dynamic scanning may be required, as also indicated in my earlier statement. Yet, also here more simplified approaches should be considered, such as the recently proposed standardized uptake ratio (SUR) which is the SUV normalized to blood pool activity . Use of SUR would, at least, partially compensate for alterations in blood pool activity and seems to outperform SUV for specific studies .…”

“…Yet, also here more simplified approaches should be considered, such as the recently proposed standardized uptake ratio (SUR) which is the SUV normalized to blood pool activity . Use of SUR would, at least, partially compensate for alterations in blood pool activity and seems to outperform SUV for specific studies . The main advantage of the use of SUR is that it can be obtained with a (short) static imaging protocol.…”