Predictive Value of Metabolic Tumor Volume Measured by 18F-FDG PET for Regional Lymph Node Status in Patients With Esophageal Cancer

Development and Validation of PET/CT-Based Nomogram for Preoperative Prediction of Lymph Node Status in Esophageal Squamous Cell Carcinoma

PURPOSE

This study was conducted to predict the lymph node status and survival of esophageal squamous cell carcinoma before treatment by PET-CT-related parameters.

METHODS

From January 2013 to July 2018, patients with pathologically diagnosed ESCC at our hospital were retrospectively enrolled. Completed esophagectomy and two- or three-field lymph node dissections were conducted. Those with neoadjuvant therapy were excluded. The first 65% of patients in each year were regarded as the training set and the last 35% as the test set. Nomogram was constructed by the "rms" package. Five-year, overall survival was analyzed based on the best cutoff value of risk score determined by the "survivalROC" package.

RESULTS

Ultimately, 311 patients were included with 209 in the training set and 102 in the test set. The positive rate of the lymph node in the training set was 36.8% and that in the test set was 32.4%. The C-index of the training set was 0.763 and the test set was 0.766. The decision curve analysis showed that it was superior to the previous methods based on lymph node uptake or long/short axis diameter or axial ratio. Risk score > 0.20 was significantly associated with 5-year, overall survival (p = 0.0015) in all patients.

CONCLUSIONS

The nomogram constructed from PET-CT parameters including primary tumor metabolic length and thickness can accurately predict the risk of lymph node metastasis in ESCC. The risk score calculated by our model accurately predicts the patient's 5-year overall survival.

The repeatability and consistency of different methods for measuring the volume parameters of the primary rectal cancer on diffusion weighted images

Background

To determine the reproducibility of measuring the gross total volume (GTV) of primary rectal tumor with manual and semi-automatic delineation on the diffusion-weighted image (DWI), examine the consistency of using the same delineation method on DWI images with different high b-values, and find the optimal delineation method to measure the GTV of rectal cancer.

Methods

41 patients who completed rectal MR examinations in our hospital from January 2020 to June 2020 were prospectively enrolled in this study. The post-operative pathology confirmed the lesions were rectal adenocarcinoma. The patients included 28 males and 13 females, with an average age of (63.3 ± 10.6) years old. Two radiologists used LIFEx software to manually delineate the lesion layer by layer on the DWI images (b=1000 s/mm2 and 1500 s/mm2) and used 10% to 90% of the highest signal intensity as thresholds to semi-automatically delineate the lesion and measure the GTV. After one month, Radiologist 1 performed the same delineation work again to obtain the corresponding GTV.

Results

The inter- and intra-observer interclass correlation coefficients (ICC) of measuring GTV using semi-automatic delineation with 30% to 90% as thresholds were all >0.900. There was a positive correlation between manual delineation and semi-automatic delineation with 10% to 50% thresholds (P < 0.05). However, the manual delineation was not correlated with the semi-automatic delineation with 60%, 70%, 80%, and 90% thresholds. On the DWI images with b=1000 s/mm2 and 1500 s/mm2, the 95% limit of agreement (LOA%) of measuring GTV using semi-automatic delineation with 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, and 90% thresholds were -41.2~67.4, -17.8~51.5, -16.1~49.3, -26.2~50.1, -42.3~57.6, -57.1~65.4, -67.3~66.5, -101.6~91.1, -129.4~136.0, and -15.3~33.0, respectively. The time required for GTV measurement by semi-automatic delineation was significantly shorter than that of manual delineation (12.9 ± 3.6s vs 40.2 ± 13.1s).

Conclusions

The semi-automatic delineation of rectal cancer GTV with 30% threshold had high repeatability and consistency, and it was positively correlated with the GTV measured by manual delineation. Therefore, the semi-automatic delineation with 30% threshold could be a simple and feasible method for measuring rectal cancer GTV.

PET/CT for Predicting Occult Lymph Node Metastasis in Gastric Cancer

A portion of gastric cancer patients with negative lymph node metastasis at an early stage eventually die from tumor recurrence or advanced metastasis. Occult lymph node metastasis (OLNM] is a potential risk factor for the recurrence and metastasis in these patients, and it is highly important for clinical prognosis. Positron emission tomography (PET)/computed tomography (CT) is used to assess lymph node metastasis in gastric cancer due to its advantages in anatomical and functional imaging and non-invasive nature. Among the major metabolic parameters of PET, the maximum standardized uptake value (SUVmax) is commonly used for examining lymph node status. However, SUVmax is susceptible to interference by a variety of factors. In recent years, the exploration of new PET metabolic parameters, new PET imaging agents and radiomics, has become an active research topic. This paper aims to explore the feasibility and predict the effectiveness of using PET/CT to detect OLNM. The current landscape and future trends of primary metabolic parameters and new imaging agents of PET are reviewed. For gastric cancer patients, the possibility to detect OLNM non-invasively will help guide surgeons to choose the appropriate lymph node dissection area, thereby reducing unnecessary dissections and providing more reasonable, personalized and comprehensive treatments.

Clinical Predictors of Locally Advanced Pathology in Esophageal Adenocarcinoma

Background

In patients with resectable esophageal adenocarcinoma (EAC), the decision for neoadjuvant treatment depends on clinical staging with endoscopic ultrasound (EUS) and positron-emission tomography (PET) scan. Patients with locally advanced EAC pathology misclassified as early EAC by clinical staging are missing the opportunity to receive neoadjuvant therapy. We aim to identify predictors of locally advanced pathology in EAC to determine more accurately those who benefit from neoadjuvant therapy. 

Methods

Retrospective study of patients who underwent upfront endoscopic or surgical resection for EAC without neoadjuvant therapy from January 2011 to December 2017 was performed. Clinical characteristics, EUS, PET scan and histologic findings were analyzed. Multivariable analysis of predictors of locally advanced stage was performed and a risk prediction score was developed.

Results

A total of 97 patients were included; 68 patients were staged as early EAC (pT1 or pT2 and pN0) and 29 patients were staged as locally advanced EAC (pT1 or pT2 with pN1 and pT3 or pT4 irrespective of N status). In a predictive model of EAC, patients presenting with dysphagia, tumor size >2 cm, exophytic mass appearance on endoscopy and absence of hiatal hernia were more likely to be have locally advanced pathology with a probability of 70% (C-statistic 0.766).

Conclusions

A risk prediction model based on the presence of dysphagia, tumor size >2 cm, exophytic mass appearance and absence of hiatal hernia can be used to identify locally advanced pathology in EAC patients.

Relative metabolic tumor burden is associated with residual lymph node status after neoadjuvant chemoradiotherapy in locally advanced esophageal cancer

BACKGROUND

Extended lymph node involvement could indicate limited survival benefit from neoadjuvant chemoradiotherapy with surgery in resectable locally advanced esophageal cancer. However, the threshold of node involvement is unclear.

METHODS

We retrospectively measured and calculated metabolic parameters derived from ¹⁸F-FDG PET/CT of the patients with nCRT and surgery. The parameters included metabolic tumor volume of the whole body (MTVwb), of the primary tumor (MTVp), of the lymph nodes (MTVn), and relative metabolic tumor burden (R-MTB, defined as the ratio of MTVwb and MTVp).

RESULTS

A total of 67 patients were enrolled in the study. The MTVp with thresholds as 3.0, 3.5, 4.0, 4.5 and 5.0 were significantly correlated with clinical T categories (Spearman's rank correlation coefficient, all P < 0.0001) and clinical tumor length categories (Spearman's rank correlation coefficient, all P ≤ 0.005). However, the MTVn were marginally correlated with clinical lymph node categories (P = 0.023). Among the 31 (31/67, 46.3%) patients with MTVn as 0 (R-MTB as 100.00%), 5 (5/5, 100.0%) were initially restaged as cLym- (MTVn as 0, R-MTB as 100.00%), while 26 (26/62, 41.9%) were initially restaged as cLym + (MTVn > 0, R-MTB > 100.00%). After nCRT, 43 (64.2%) patients achieved ypN0. The univariate and multivariate regression revealed that R-MTB (≤ 106.00% vs. > 106.00%) was an independent factor associated with ypN + status (OR 0.093, 95%CI 0.023-0.378, P = 0.001).

CONCLUSION

The preliminary study revealed a great heterogeneity in clinical lymph node categories in esophageal cancer. It suggested that R-MTB was significantly associated with ypN status after neoadjuvant chemoradiotherapy in locally advanced esophageal cancer. The findings with the indications needed to be further studied in a prospective study with a large patient cohort.

Novel 5-point 18-FDG-PET/CT visual scoring system for assessing treatment response in patients with oesophageal or gastro-oesophageal junction carcinoma

INTRODUCTION

The purpose of this study was to investigate the prognostic utility and reproducibility of a qualitative 5-point 18-fluorodeoxyglucose (FDG)-PET primary visual score (PVS) in patients with oesophageal and gastro-oesophageal junction (GOJ) cancer.

METHODS

This was a retrospective review of patients with histologically proven oesophageal or GOJ cancer who received curative intent therapy. Clinical, pathological and imaging data were extracted from electronic medical records. Patients were required to have pre-treatment and post-treatment FDG-PET scans, that were evaluated with a 5-point primary visual score (prePVS, postPVS). The changes in PVS (ΔPVS) were correlated with progression-free survival and overall survival. Interobserver variability was assessed using Cohen's Kappa intraclass correlation and agreement.

RESULTS

Sixty-seven patients were retrospectively identified. Two (3%), 36 (54%) and 29 (43%) of the patients had stage I, II and III disease respectively. Twenty-five (37%) patients had squamous cell carcinoma. Thirty-seven (55%) patients proceeded onto surgical resection. postPVS was associated with both PFS (P = 0.013) and OS (P = 0.0002). ΔPVS predicted for PFS (P = 0.002) and OS (P = 0.0003). When thresholds of response were considered, agreement was 80.6% (K = 0.78) and 74.6% (K = 0.69) for postPVS and ΔPVS respectively.

CONCLUSION

Qualitative assessment of oesophageal and GOJ cancers utilising FDG-PET is reproducible and may be able to prognosticate outcomes in patients undergoing treatment. Prospective validation is required.

The relationship between FDG PET/CT-defined metabolic parameters and the histopathological subtype of oesophageal carcinomas

Purpose

18F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET) combined with computed tomography (CT) scan is accepted as a standard tool in the staging of oesophageal cancer (OC). Histological subtype of tumour is known to be a major determinant of prognosis and metabolic behaviour. In this study, we aimed to evaluate the effect of histological subtypes of OC on standard uptake value (SUV_max), metabolic tumour volume (MTV), and total lesion glycolysis (TLG) obtained by PET/CT, and also to compare this effect with prognosis.

Material and methods

Images and clinical course data of 57 patients who were diagnosed with EC and treated in our hospital between 2009 and 2016 were evaluated in a retrospective manner. PET/CT images were re-analysed in terms of metabolic parameters, and observations were compared with histological subtypes.

Results

No significant difference was observed between histological subtypes with SUV_max, overall survival (OS), or progression-free survival (PFS). Thus, MTV was observed to be related with histological subtype; MTV values of adenocancer patients were significantly higher than those of squamous cell cancer patients.

Conclusions

Metabolic tumour volume was related with histological subtype of OC, but clinical staging, TLG, and SUV_max values were not related with histological subtype, which may suggest the use of MTV as a routine parameter for OC and inclusion of MTV observations in prognostic scoring.

Prediction of lymph node metastasis by PET/CT metabolic parameters in patients with esophageal squamous cell carcinoma

OBJECTIVE

The aim of this study was to investigate the capability of F-FDG PET/computed tomography (CT)-related metabolic parameters to predict lymph node metastasis (LNM) and occult lymph node metastasis (OLNM) in patients with esophageal squamous cell carcinoma (ESCC).

METHODS

Totally 84 patients undergoing curative esophagectomy with lymph node dissection were enrolled in this study. Metabolic tumor volume (MTV) was measured using threshold-based methods with a threshold of 40% maximum standardized uptake value (SUVmax). The derivative of the volume (V)-threshold (T) function (volume difference/threshold difference) was defined as the heterogeneity factor (HF). In addition, SUVmax, SUVmean, total lesion glycolysis (TLG), maximum tumor-to-blood SUV ratio (SURmax), SURmean and several clinicopathologic parameters were analyzed to identify risk factors of LNM and OLNM.

RESULTS

SUVmax, SUVmean, MTV, TLG, SURmax, SURmean and HF were significantly different between LNM (+) and LNM (-). The optimal cut-off values of those parameters were 12.5, 8.34, 15.01, 117.185, 7.885, 4.855 and 0.300, respectively. Logistic regression analysis showed that MTV (OR = 1.127, P = 0.04) and SURmax (OR = 1.446, P = 0.004) were independent predictors of LNM, with sensitivity and specificity were 51.2%, 83.7% vs. 53.7%, 79.1%. In univariate and multivariate analysis, MTV was the sole parameter associated with OLMN (P = 0.024).

CONCLUSION

MTV and SURmax were statistically significant predictors of LNM in patients with ESCC, while MTV was a predictor of OLNM. High SURmax and MTV may indicate that the treatment planning should be tailored, which may improve patient prognosis.

Clinical Significance of 18F-Fluorodeoxyglucose-Positron Emission Tomography-Positive Lymph Nodes to Outcomes of Trimodal Therapy for Esophageal Squamous Cell Carcinoma

BACKGROUND

The clinical significance of lymph node (LN) status determined by preoperative ¹⁸F-fluorodeoxyglucose-positron emission tomography (FDG-PET) has not been investigated in patients with locally advanced esophageal squamous cell carcinoma (ESCC) treated with neoadjuvant chemoradiotherapy (NCRT) followed by surgery (trimodal therapy).

METHODS

This study reviewed 132 consecutive patients with ESCC who had been preoperatively evaluated using FDG-PET before and after NCRT to analyze associations among LN status according to PET findings, pathologic LN metastasis, and prognosis of ESCC after trimodal therapy.

RESULTS

Lymph nodes that were PET-positive both before and after NCRT comprised significant predictive markers of pathologic LN metastasis in station-by-station analyses (sensitivity, specificity, and accuracy respectively 41.7%, 95.0%, and 92.7% before, and 12.0%, 99.4%, and 95.6% after NCRT; both p < 0.0001). The numbers of LNs evaluated using PET before and after NCRT were significantly associated with those of pathologic metastatic LNs. Uni- and multivariable analyses selected LN status determined by PET before NCRT as a significant independent predictor of both recurrence-free [LN-negative vs LN-positive: hazard ratio (HR) 1.90; 95% confidence interval (CI) 1.02-3.23; p = 0.045] and overall survival (HR 2.62; 95% CI 1.29-5.30; p = 0.01).

CONCLUSIONS

The status of LN determined by preoperative FDG-PET is significantly associated with pathologic LN status and the prognosis of ESCC with trimodal therapy. Thus, FDG-PET is a useful diagnostic tool for preoperative prediction of pathologic LN metastasis and survival among patients with ESCC.

Peak of Standardized Uptake Value in Oral Cancer Predicts Survival Adjusting for Pathological Stage

BACKGROUND/AIM

To predict survival outcomes of different patients with the same stage of disease is difficult. The possible correlation between ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) uptake parameters and survival outcomes was investigated in oral squamous cell carcinoma patients by multivariate analysis adjusted for the pathological stage according to the 8th edition of the tumor-node-metastasis (TNM) classification of the Union for International Cancer Contro.

PATIENTS AND METHODS

¹⁸F-FDG-uptake parameters of 28 patients were assessed by positron emission tomography with computed tomography (PET/CT).

RESULTS

A peak of standardized uptake value of primary tumor (p-SUVpeak) of ≥14.1 was significantly correlated with shorter overall survival by univariate and multivariate analyses adjusted for the pathological TNM stage. A p-SUVpeak of ≥14.1 was significantly associated with shorter local recurrence-free survival and disease-free survival.

CONCLUSION

A higher p-SUVpeak on pretreatment ¹⁸F-FDG-PET/CT is a prognostic parameter of identifying lower survival outcomes.

Prognostic value of metabolic tumor volume and total lesion glycolysis in esophageal carcinoma patients treated with definitive chemoradiotherapy

PURPOSE

The aim of this study was to evaluate the prognostic importance metabolic tumor volume (MTV), total lesion glycolysis (TLG), and standardized uptake value (SUV) in patients with esophageal cancer treated with definitive chemoradiotherapy.

PATIENTS AND METHODS

Seventy-two esophageal cancer patients treated with definitive chemoradiotherapy [57 (79%) patients] or definitive radiotherapy [15 (21%) patients] were retrospectively analyzed. The regions equal to or greater than SUV of 2.5 were selected to delineate MTV and TLG was calculated by multiplying the mean SUV by the MTV of the primary lesions. The overall survival (OS) and disease-free survival (DFS) were evaluated for all patients and also patients with squamous cell carcinoma.

RESULTS

The median survival time was 13.4 months (range: 1.8-119.3 months) for all patients. Maximum SUV, mean SUV, MTV, and TLG values were significantly higher in patients with extensive T-stage (T3-T4) compared with patients with T1-T2 disease. Patients with regional lymph node metastasis had significantly higher MTV and TLG values compared with patients with no lymph node metastasis. On multivariate analysis, MTV, TLG, presence of lymph node metastasis, and lack of concurrent chemotherapy were negative significant prognostic factors for OS and DFS for the entire cohort and for patients with squamous cell carcinoma esophageal cancer.

CONCLUSION

Metabolic volumes (MTV and TLG), regional lymph node metastasis, and concurrent chemotherapy are major prognostic factors for DFS and OS in patients with esophageal carcinoma. In addition, MTV and TLG are important in predicting nodal metastasis, and together with metabolic volumes, SUV are associated significantly with local tumor invasion.

Diagnostic Value of Volume-Based Fluorine-18-Fluorodeoxyglucose PET/CT Parameters for Characterizing Thyroid Incidentaloma

Objective

To assess clinical value of fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) for differentiation of malignant from benign focal thyroid incidentaloma.

Materials and Methods

This retrospective study included 99 patients with focal thyroid incidentaloma of 5216 non-thyroid cancer patients that had undergone PET/CT. PET/CT semi-quantitative parameters, volume-based functional parameters, metabolic tumor volume (MTV), and total lesion glycolysis (TLG) of thyroid incidentaloma were assessed. Receiver-operating characteristic (ROC) analysis was conducted and areas under the curve (AUC) were compared by Hanley and McNeil test to evaluate usefulness of maximum standardized uptake value (SUVmax), MTV and TLG, as markers for differentiating malignant from benign thyroid incidentalomas.

Results

Of 99 thyroid incidentalomas, 64 (64.6%) were malignant and 35 (35.4%) were benign. Malignant thyroid incidentalomas were larger (1.8 cm vs. 1.3 cm, p = 0.006), and had higher SUVmax (11.3 vs. 4.8, p < 0.001), MTV (all p < 0.001) and TLG (all p < 0.001) than benign. TLG 4.0 had the highest performance for differentiation of malignant from benign thyroid incidentaloma in all semi-quantitative parameters with AUC 0.895 by ROC curve analysis. AUC (TLG 4.0) was significantly larger than AUC (SUVmean), AUC (MTV 2.5), AUC (MTV 3.0), AUC (MTV 3.5), AUC (TLG 2.5), and AUC (TLG 3.0), respectively (all, p < 0.05). There was no statistical difference between AUC (TLG 4.0) and AUC (SUVmax) (p > 0.05). A threshold TLG 4.0 of 2.475 had 81.3% sensitivity and 94.3% specificity for identifying malignant thyroid incidentalomas.

Conclusion

Volume-based PET/CT parameters could potentially have clinical value in differential diagnosis of thyroid incidentaloma along with SUVmax.

Comparative effectiveness of upfront esophagectomy versus induction chemoradiation in clinical stage T2N0 esophageal cancer: A decision analysis

OBJECTIVES

We compared the effectiveness of upfront esophagectomy versus induction chemoradiation followed by esophagectomy for overall survival in patients with clinical T2N0 (cT2N0) esophageal cancer. We also assessed the influence of the diagnostic uncertainty of endoscopic ultrasound on the expected benefit of chemoradiation.

METHODS

We created a decision analysis model representing 2 treatment strategies for cT2N0 esophageal cancer: upfront esophagectomy that may be followed by adjuvant therapy for upstaged patients and induction chemoradiation for all patients with cT2N0 esophageal cancer followed by esophagectomy. Parameter values within the model were obtained from published data, and median survival for pathologic subgroups was derived from the National Cancer Database. In sensitivity analyses, staging uncertainty of endoscopic ultrasound was introduced by varying the probability of pathologic upstaging.

RESULTS

The baseline model showed comparable median survival for both strategies: 48.3 months for upfront esophagectomy versus 45.9 months for induction chemoradiation and surgery. The sensitivity analysis demonstrated induction chemoradiation was beneficial, with probability of upstaging > 48.1%, which is within the published range of 32% to 65% probability of pathologic upstaging after cT2N0 diagnosis. The presence of any of 3 key variables (size larger than 3 cm, high grade, or lymphovascular invasion) was associated with > 48.1% risk of upstaging, thus conferring a survival advantage to induction chemoradiation.

CONCLUSIONS

The optimal treatment strategy for cT2N0 esophageal cancer depends on the accuracy of endoscopic ultrasound staging. High-risk features that confer increased probability of upstaging can inform clinical decision making to recommend induction chemoradiation for select cT2N0 patients.

Combined imaging with 68Ga-DOTA-TATE and 18F-FDG PET/CT on the basis of volumetric parameters in neuroendocrine tumors

AIM

To assess the additional contribution of the combined imaging approach with Ga-DOTA-TATE and fluorine-18 fluorodeoxyglucose (F-FDG) on the basis of volumetric parameters in neuroendocrine tumors (NETs).

MATERIALS AND METHODS

Forty-one patients with NET (19 women, 22 men; age range: 30-79 years; mean age: 56.7±12.3 years) underwent Ga DOTA-TATE and F-FDG PET/computed tomography (CT) imaging. Within the drawn regions of interest, in addition to evaluating the maximum and mean standardized uptake values (SUVmax and SUVmean), the metabolic tumor volume (MTV) and total lesion glycolysis (TLG) in F-FDG PET/CT imaging, and the somatostatin receptor density and total lesion somatostatin receptor expression (TLSRE) in Ga somatostatin receptor imaging (SRI) were measured. The patients were graded on the basis of the proliferation index: well (G1; Ki-67 ≤2), moderately (G2; Ki-67=3-20), and poorly (G3; Ki-67>20) differentiated groups.

RESULTS

Of the 41 NET patients, 22, 14, and five were in the G1 (53.7%), G2 (34.1%), and G3 (12.2%) groups, respectively. Liver metastases had significantly higher TLSRE values than the TLG values. Ki-67 levels showed a positive correlation with the primary tumor MTV and TLG values. Cg-A levels had a positive correlation with the volumetric parameters of the whole-body tumor burden (P<0.001).

CONCLUSION

Ga SRI and F-FDG PET/CT provide complementary information on treatment protocol and response assessment. While assessing the prognosis and tumor aggressiveness, lesions and whole-body tumor burdens can be calculated on the basis of volumetric parameters by F-FDG PET/CT using MTV and TLG, and by Ga SRI using somatostatin receptor density and TLSRE.

Metabolic tumor volume provides complementary prognostic information to EUS staging in esophageal and junctional cancer

To determine the correlation between 18F-fluorodeoxyglucose positron emission tomography-computed tomography (PET-CT) derived esophageal tumor parameters [maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV)] and endoscopic ultrasound (EUS) derived tumor parameters (T stage, N stage) and their prognostic implications. 150 consecutive patients with cancer of the esophagus or esophagogastric junction underwent staging PET-CT and staging EUS. PET-CT derived SUVmax and MTV of the primary tumor was recorded. EUS evaluated T and N stage. Relationships between parameters were investigated using the Mann-Whitney U tests, survival analysis performed using Kaplan-Meier and independent prognostic factors determined using Cox regression multivariate analysis. A significant difference in MTV was noted between EUS T1/T2 tumors (median 6.7 cm3) and EUS T3/T4 tumors (median 35.7 cm3; P < 0.0001). An MTV of <23.4 cm3 (P = 0.0001), SUVmax < 4.1 (P = 0014), EUS T stage (P < 0.0001), EUS N stage (P < 0.0001), and clinical stage (P < 0.0001) were all significantly associated with survival, with MTV <23.4 cm3 (P = 0.004), EUS T stage (P = 0.01), and EUS N stage (P = 0.01) significant in multivariate analysis. MTV, a volumetric parameter of PET-CT, has more prognostic importance than SUVmax and provides valuable prognostic information in esophageal and junctional cancer, along with EUS T and N stage. MTV provides complementary information to EUS and should be included in the staging of esophageal and junctional cancer.

FDG-PET/CT lymph node staging after neoadjuvant chemotherapy in patients with adenocarcinoma of the esophageal-gastric junction

Objectives

The aim of the analysis was to assess the accuracy of various FDG-PET/CT parameters in staging lymph nodes after neoadjuvant chemotherapy.

Methods

In this prospective study, 74 patients with adenocarcinoma of the esophageal–gastric junction were examined by FDG-PET/CT in the course of their neoadjuvant chemotherapy given before surgical treatment. Data from the final FDG-PET/CT examinations were compared with the histology from the surgical specimens (gold standard). The accuracy was calculated for four FDG-PET/CT parameters: (1) hypermetabolic nodes, (2) large nodes, (3) large-and-medium large nodes, and (4) hypermetabolic or large nodes.

Results

In 74 patients, a total of 1540 lymph nodes were obtained by surgery, and these were grouped into 287 regions according to topographic origin. Five hundred and two nodes were imaged by FDG-PET/CT and were grouped into these same regions for comparison. In the analysis, (1) hypermetabolic nodes, (2) large nodes, (3) large-and-medium large nodes, and (4) hypermetabolic or large nodes identified metastases in particular regions with sensitivities of 11.6%, 2.9%, 21.7%, and 13.0%, respectively; specificity was 98.6%, 94.5%, 74.8%, and 93.6%, respectively. The best accuracy of 77.7% reached the parameter of hypermetabolic nodes. Accuracy decreased to 62.0% when also smaller nodes (medium-large) were taken for the parameter of metastases.

Conclusions

FDG-PET/CT proved low sensitivity and high specificity. Low sensitivity was based on low detection rate (32.6%) when compared nodes imaged by FDG-PET/CT to nodes found by surgery, and in inability to detect micrometastases. Sensitivity increased when also medium-large LNs were taken for positive, but specificity and accuracy decreased.

The prognostic value of total lesion glycolysis via 18F-fluorodeoxyglucose PET-CT in surgically treated esophageal squamous cell carcinoma

OBJECTIVE

In addition to staging, the identification of prognostic factors is important for predicting survival in patients with esophageal cancer after esophagectomy. The present study was performed to document the prognostic role of total lesion glycolysis (TLG) in postoperative patients.

METHODS

We retrospectively reviewed the records of 50 patients with esophageal squamous cell carcinoma who underwent surgical resection and complete lymph node dissection after positron emission tomography-computed tomography (PET-CT). A volume of interest was drawn on the primary lesion and suspected metastatic lymph nodes, and the maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), TLG of the primary lesion (TLGp), and whole-body TLG (TLGwb) were measured using an SUV cutoff of 2.5.

RESULTS

The study population included 50 patients with a mean age of 63.14 ± 8.18 years: 12 (24%) were reported as stage I, 13 (26%) as stage II, and 25 (50%) as stage III. The median follow-up period was 20.46 months, and recurrences occurred in 17 patients. The mean SUVmax, MTV, TLGp, and TLGwb were 11.11 ± 6.40, 20.47 ± 22.88, 122.54 ± 180.98, and 129.37 ± 193.66, respectively. On the multivariate analysis, TLGp was a risk factor for disease-free survival (DFS) [hazard ratio (HR) = 1.002, p = 0.026], and TLGwb was a risk factor for DFS (HR = 1.002, p = 0.021) and overall survival (OS) (HR = 1.002, p = 0.044). The 3-year OS rates were 66.1% in patients with low TLGwb (≤ 41.45) and 33.3% in those with high TLGwb (>41.45; p = 0.004). The concordance index of the TLGwb was 0.752 (95% CI 0.659-0.845).

CONCLUSION

TLGwb is a significant prognostic factor for OS and DFS in patients with surgically treated esophageal squamous cell carcinoma.

Relationship Between the Size of Metastatic Lymph Nodes and Positron Emission Tomographic/Computer Tomographic Findings in Patients with Esophageal Squamous Cell Carcinoma

BACKGROUND

We measured the sizes of metastatic lymph nodes and the relationships thereof by (18)F-fluorodeoxyglucose positron emission tomography/computer tomography (PET/CT). We identified risk factors for nodal upstaging in patients with esophageal squamous cell carcinoma (ESCC).

METHODS

Eighty-five patients with ESCC who underwent esophagectomy with extensive mediastinal lymphadenectomy were assessed. Two radiologists blinded to pathology data reviewed PET/CT scans, evaluating both primary tumors and lymph node involvement. A pathologist examined all metastatic lymph nodes in terms of maximal diameter (LNmax), the size of the metastatic focus (Fmax), and the metastasis occupation ratio (MOR = Fmax/LNmax).

RESULTS

The maximal tumor length averaged 2.9 ± 0.2 cm and the mean SUVmax of the primary lesion 5.3 ± 0.5. On PET/CT scans, 26 (30.6 %) patients exhibited nodal metastasis and 59 (69.4 %) did not. Pathology grades of pN0, pN1, pN2, and pN3 were assigned to 45 (52.9 %), 24 (28.2 %), 13 (15.3 %), and 3 (3.5 %) patients, respectively. Nodal upstaging was evident in 29 (34.1 %) cases. In 123 metastatic nodes of 4212 nodes dissected, the LNmax was 6.60 ± 0.39 mm, the Fmax 4.47 ± 0.35 mm, and the MOR 0.68 ± 0.03. Of 123 nodes, 85 (69.1 %) were retrieved from PET-negative stations, and the LNmax and Fmax values of these nodes were 5.88 ± 0.42 and 3.75 ± 0.31 mm, respectively. Upon multivariate analysis, tumor length (OR 1.666, p = 0.019) and lymphovascular invasion (OR 41.038, p < 0.001) were risk factors for nodal upstaging.

CONCLUSION

A significant proportion of nodal metastases were too small to detect via PET/CT imaging. Therefore, meticulous lymph node dissection might be helpful in ESCC patients.

Total 18F-FDG PET/CT Metabolic Tumor Volume Is Associated With Postoperative Biochemical Response in Patients With Metastatic Pheochromocytomas and Paragangliomas

OBJECTIVE

The aim of this pilot study was to determine if metabolic tumor volume (MTV) and total lesion glycolysis (TLG) could serve as predictors of biochemical remission and pharmacotherapy-free interval in patients with metastatic pheochromocytomas (PCCs) and paragangliomas (PGLs).

BACKGROUND

Patients with metastatic PCCs/PGLs have a high rate of biochemical recurrence, which can be associated with increased cardiovascular morbidity. Predictors of biochemical response are needed to guide and select patients who may benefit from therapy.

METHODS

Whole body MTV and TLG was calculated from preoperative 18F-FDG PET/CT scans and analyzed as marker of biochemical response and pharmacotherapy-free interval.

RESULTS

Seventeen patients underwent a total of 19 procedures, with a median follow-up time of 26.4 months. Whole body MTV of patients with biochemical recurrence (n = 13, mean 73.8  mL) was higher than those who had a biochemical response (n = 6, mean 14.7  mL, P = 0.05). Patients with low MTV (<37.2  mL) had an improved durable partial biochemical response (P < 0.05), and a statistical trend for complete biochemical remission (P = 0.07) and pharmacotherapy-free interval (P = 0.06). In 8 patients with metastatic disease outside the abdomen, 4 patients had less than 35% of their disease burden outside the abdomen and these patients had a more durable partial biochemical response compared to patients with greater than 35% of their disease burden outside the abdomen (P < 0.05).

CONCLUSIONS

Whole body MTV and TLG represents novel and valuable predictors of biochemical response for patients with metastatic PCCs and PGLs. A larger prospective study should be performed to validate these findings.

Tumor volume of resectable gastric adenocarcinoma on multidetector computed tomography: association with N categories

OBJECTIVE

To determine whether the gross tumor volume of resectable gastric adenocarcinoma on multidetector computed tomography could predict the presence of regional lymph node metastasis and could determine N categories.

MATERIALS AND METHODS

A total of 202 consecutive patients with gastric adenocarcinoma who had undergone gastrectomy 1 week after contrast-enhanced multidetector computed tomography were retrospectively identified. The gross tumor volume was evaluated on multidetector computed tomography images. Univariate and multivariate analyses were performed to determine whether the gross tumor volume could predict regional lymph node metastasis, and the Mann-Whitney U test was performed to compare the gross tumor volume among N categories. Additionally, a receiver operating characteristic analysis was performed to identify the accuracy of the gross tumor volume in differentiating N categories.

RESULTS

The gross tumor volume could predict regional lymph node metastasis (p<0.0001) in the univariate analysis, and the multivariate analyses indicated that the gross tumor volume was an independent risk factor for regional lymph node metastasis (p=0.005, odds ratio=1.364). The Mann-Whitney U test showed that the gross tumor volume could distinguish N0 from the N1-N3 categories, N0-N1 from N2-N3, and N0-N2 from N3 (all p<0.0001). In the T1-T4a categories, the gross tumor volume could differentiate N0 from the N1-N3 categories (cutoff, 12.3 cm3), N0-N1 from N2-N3 (cutoff, 16.6 cm3), and N0-N2 from N3 (cutoff, 24.6 cm3). In the T4a category, the gross tumor volume could differentiate N0 from the N1-N3 categories (cutoff, 15.8 cm3), N0-N1 from N2-N3 (cutoff, 17.8 cm3), and N0-N2 from N3 (cutoff, 24 cm3).

CONCLUSION

The gross tumor volume of resectable gastric adenocarcinoma on multidetector computed tomography could predict regional lymph node metastasis and N categories.

Determination of regional lymph node status using (18)F-FDG PET/CT parameters in oesophageal cancer patients: comparison of SUV, volumetric parameters and intratumoral heterogeneity

OBJECTIVE

We aimed to investigate whether the standardized uptake values, volumetric parameters and intratumoral heterogeneity of fluorine-18-fludeoxyglucose ((18)F-FDG) uptake could predict regional lymph node (rLN) metastasis in oesophageal cancer.

METHODS

51 patients with surgically resected oesophageal cancer were included in the present study. The (18)F-FDG positron emission tomography (PET)/CT findings and rLN metastasis were compared with the histopathological results. The intratumoral metabolic heterogeneity was represented by the heterogeneity factor (HF), which was determined for each patient. Univariate and multivariate analyses were used to analyse the associations between the rLN metastasis and clinical findings, standardized uptake values, metabolic tumour volume (MTV), total lesion glycolysis (TLG) and HF.

RESULTS

The rLN(+) group showed statistically significant higher values of MTV (median, 13.59 vs 6.6; p = 0.0085), TLG (median, 119.18 vs 35.96; p = 0.0072) and HF (median, 3.07 vs 2.384; p = 0.0002) than the rLN(-) group. Univariate analysis showed that maximum standardized uptake value, mean standardized uptake value, MTV, TLG and HF were significantly associated with pathologic rLN involvement. However, in multivariate analysis, the HF was a potent associated factor for the prediction of pathologic rLN metastasis in oesophageal cancer.

CONCLUSION

In conclusion, (18)F-FDG PET/CT parameters such as maximum standardized uptake value, mean standardized uptake value, MTV, TLG and HF were useful for the prediction of pathologic rLN status in patients with oesophageal cancer. However, HF might be the most powerful predictor of rLN metastasis of patients with oesophageal cancer.

ADVANCES IN KNOWLEDGE

Assessment of intratumoral heterogeneity of (18)F-FDG PET/CT may be a useful adjunct for rLN staging of oesophageal cancer.

Prognostic value of FDG PET/CT in head and neck squamous cell carcinomas

Introduction

The purpose of this study was to evaluate the use of ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) to identify the presence of cervical lymph nodes metastases and extracapsular spread with histologic correlations in head and neck squamous cell carcinoma.

Methods

The medical records of 54 patients who underwent ¹⁸F-FDG PET/CT for head and neck squamous cell carcinoma before surgery were reviewed. Receiver operating characteristic (ROC) analysis was performed to differentiate patients with cervical lymph node metastasis from those without lymph node metastasis. The same statistical analysis was done to differentiate cervical lymph nodes with extracapsular spread from those without extracapsular spread.

Results

Metastatic disease was diagnosed histologically in 49% (26 of 54) of the patients. Extracapsular spread was present in ten of the 54 patients (19%). When ROC curve analysis and maximum standardized uptake (SUV_max) values were used to detect cervical lymph node metastasis, the area under the ROC curve was 0.96 and the optimal cutoff value for SUV_max was 4.05 based on ROC curve analysis. The sensitivity and specificity of SUV_max for the detection of cervical lymph node metastasis using this cutoff point were 92% and 88%, respectively. When ROC curve analysis and SUV_max values were used in order to detect extracapsular spread, the area under the ROC curve was 0.86, and the optimal cutoff value for SUV_max was 4.15 based on ROC curve analysis. Using this cutoff value, the sensitivity and specificity of SUV_max for the detection of extracapsular spread were 83% and 88%, respectively.

Conclusion

In our study, a median ¹⁸F-FDG PET/CT SUV_max cutoff value of 4.15 was found to be related with cervical lymph node metastasis and extracapsular spread in patients with head and neck cancer.

High metabolic tumor volume and total lesion glycolysis are associated with lateral lymph node metastasis in patients with incidentally detected thyroid carcinoma

OBJECTIVE

The objective of this study was to investigate whether total lesion glycolysis (TLG) and metabolic tumor volume (MTV) measured by ¹⁸F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography/computed tomography (PET/CT) could predict the aggressiveness and lymph node metastasis (LNM) in patients with incidentally detected differentiated thyroid carcinoma.

METHODS

A total 358 patients with focal FDG-avid thyroid incidentaloma during cancer evaluation were enrolled. Among 235 patients in whom fine-needle aspiration biopsy was performed, 51 patients underwent total thyroidectomy with LN dissection. We analyzed the relationship between volume-based parameters and clinicopathologic characteristics.

RESULTS

The mean age and tumor size were 57.1 ± 11.3 years and 1.15 ± 0.81 cm, respectively. The prevalence of malignancy was 21.7 % (51/235). When SUV(max) > 5.91, MTV2.5 > 2.05 cm³, and TLG2.5 > 9.09 were used as cutoff points, sensitivity, specificity, and area under curve (AUC) for prediction of lateral LNM were 77.9, 69.1 %, 0.716 (P = 0.047), 77.8, 88.1 %, 0.839 (P < 0.001), 77.8, 85.1 %, and 0.815 (P = 0.002), respectively. However, MTV and TLG had no value in prediction of central LNM, extrathyroidal extension, and multifocality. On comparison ROC curve analysis, the MTV and TLG showed the statistical differences for the prediction of lateral LNM compared with SUV(max) (all P's < 0.05).

CONCLUSIONS

This study has shown for the first time that volume-based PET functional parameters had a significant value for the prediction of lateral LNM in incidentally detected PTC. These results suggest that higher MTV and TLG can be potential new risk factors for preoperative risk stratification. The usefulness of TLG and MTV in preoperative risk stratification in patients with PTC needs to be confirmed in further large studies.

Predictive value of volumetric parameters measured by F-18 FDG PET/CT for lymph node status in patients with surgically resected rectal cancer

OBJECTIVE

The objective of this study was to investigate the predictive role of volumetric parameters such as metabolic tumor volume (MTV) and total lesion glycolysis (TLG) measured by F-18 FDG PET/CT for regional lymph node (rLN) metastasis in rectal cancer patients.

METHODS

Retrospectively, 74 rectal cancer patients were enrolled. All patients received surgical treatment and F-18 FDG PET/CT at diagnosis. The F-18 FDG PET/CT findings of primary cancer and rLN involvement were compared with the pathologic diagnosis within 5 weeks after operation. Univariate and multivariate analyses were used to analyze the associations among the pathologic LN status and age, sex, T stage, AJCC stage, SUVmax, lymphatic invasion, venous invasion, neural invasion, and volumetric parameters.

RESULTS

The LN (+) group showed statistically significant higher values of MTV2.5 (p < 0.0001), MTV3 (p < 0.0001), MTV3.5 (p = 0.0001), TLG2.5 (p = 0.0007), TLG3 (p = 0.0011), and TLG3.5 (p = 0.0024). In univariate analysis, T stage, AJCC stage, neural invasion, and volumetric parameters were factors significantly associated with pathologic LN involvement. However, in multivariate analysis, advanced T stage, high AJCC stage, MTV2.5, and TLG2.5 were associated with pathologic LN involvement in rectal cancer.

CONCLUSION

This study showed that, not only T stage and AJCC stage, but also volumetric parameters such as MTV2.5 and TLG2.5 are useful factors for the prediction of pathologic LN status in rectal cancer patients.

Prognostic Value of Metabolic Tumor Volume Measured by 18F-FDG PET/CT in Esophageal Cancer Patients

Objective: In this study, we aimed to explore prognostic importance of definition of preoperative metabolic tumor volume in esophageal cancer patients.

Methods: 22 patients who have histologically proven stage IIA-III esophageal cancer and underwent ¹⁸F-FDG PET/CT for preoperative staging of disease were included to the study. After ¹⁸F-FDG PET/CT, all the patients underwent surgery within 4 weeks period. Patients have been followed up until death or Sept 15^th, 2012. Dates of death were recorded for survival analysis. During evaluation of ¹⁸F-FDG PET/CT images, metabolic tumor volumes were calculated by drawing the isocontour region of interests from all visually positive FGD uptake lesions.

Results: 22 patients (15M, 7F; mean age: 65.1±8.4, min-max:48-80) underwent ¹⁸F-FDG PET/CT for preoperative staging of esophageal cancer. Preoperative diagnosis was squamous cell and adeno cancer in 17 (%77) and 5 (%23) patients, respectively. Location of primary tumor is distal, proximal and mid-esophagus in 13 (%59), 6 (%27) and 3 (%13) patients, respectively. Primary tumor of all the patients were FDG avid (mean SUV_max: 18.85±7.0; range: 5.5-35.1). Additionally, ¹⁸F-FDG uptake was seen in mediastinal lymph nodes in 13 patients (5.45±8.15; range: 2.6-29.9). Mean metabolic tumor volumes of primary esophageal lesions were calculated as 8.77±8.46cm³ (range: 2.3-34.2). Mean MTV of lymph nodes was 2.44±1.01cm³ (range: 0.4-3.6). Mean total metabolic tumor volume was calculated as 9.99±8.58cm³ (range: 2.3-27.3). 10 patients died during 447±121 days follow-up period. Mean survival time was 11.9±1.5 months (95%CI: 8.99-14.74) for entire patient group. Total metabolic tumor volume had a significant effect on survival (p=0.045) according to Cox proportional hazards regression analysis. One unit increase in MTV caused 1.1 (95%CI:1.003-1.196) fold increase in hazard, at any time.

Conclusion: Definition of preoperative metabolic tumor volume has a prognostic value in the prediction of postoperative survival times. Patients who have higher preoperative metabolic tumor volumes could be good candidates for more aggressive chemo-radiation therapy regiments.

Conflict of interest:None declared.

Predictive and prognostic value of metabolic tumour volume and total lesion glycolysis in solid tumours

Data available in patients suffering from squamous cell carcinoma of the head and neck, lung carcinoma, oesophageal carcinoma and gynaecological malignancies suggest that metabolic tumour volume and to a lesser extent total lesion glycolysis have the potential to become valuable in the imaging of human solid tumours as prognostic biomarkers for short- to intermediate-term survival outcomes, adding value to clinical staging, for assessment of response to treatment with neoadjuvant and concurrent chemotherapy, and for treatment optimization; for example, based on early treatment response assessment using changes in metabolic tumour volume over time, it might be possible to select patients who require a more aggressive treatment to improve their outcome. Prospective studies enrolling consecutive patients, adopting standardized protocols for FDG PET acquisition and processing, adjusting for potential confounders in the analysis (tumour size and origin) and determining the optimal methodology for determination of these novel markers are mandatory.

Tumour size of resectable oesophageal squamous cell carcinoma measured with multidetector computed tomography for predicting regional lymph node metastasis and N stage

OBJECTIVES

To determine whether and how tumour size of resectable oesophageal squamous cell carcinoma (ESCC) measured with multidetector CT could predict regional lymph node metastasis (LNM) and N stage.

METHODS

Two hundred five patients with ESCC underwent radical oesophagectomy with three-field lymphadenectomy less than 3 weeks after contrast-enhanced CT. Tumour size of the ESCC (tumour length, maximal thickness and gross tumour volume, GTV) was measured on CT. Statistical analyses were performed to identify whether tumour size could predict regional LNM and N stage, and to determine how to use the size of ESCC to predict N stage.

RESULTS

Univariate analysis showed that tumour size could predict regional LNM (all P < 0.05). Logistic regression analysis revealed that GTV could independently predict regional LNM (P = 0.021, odds ratio = 1.813). Mann-Whitney tests showed that tumour size could distinguish grouped N stages (all P < 0.05). GTV might be a differentiating indicator between N0 and N1-3 stages (cutoff, 14.4 cm(3)), between N0-1 and N2-3 (cutoff, 15.9 cm(3)), and between N0-2 and N3 (cutoff, 26.1 cm(3)), with sensitivity of 76%, 63% or 75%, and specificity of 75%, 61% and 81%, respectively.

CONCLUSIONS

The GTV of ESCC measured with CT could be an indicator for predicting regional LNM and grouped N stages.

KEY POINTS

• Multidetector computed tomography (MDCT) allows accurate assessment of oesophageal tumour size • For resectable squamous cell tumours, size helped predict regional lymph node involvement • Gross tumour volume may predict the N stage of oesophageal squamous cell carcinoma.