Influence of the baseline 18F-fluoro-2-deoxy-D-glucose positron emission tomography results on survival and pathologic response in patients with gastroesophageal cancer undergoing chemoradiation

Association of dynamic contrast-enhanced MRI and 18F-Fluorodeoxyglucose PET/CT parameters with neoadjuvant therapy response and survival in esophagogastric cancer

INTRODUCTION

Better predictive markers are needed to deliver individualized care for patients with primary esophagogastric cancer. This exploratory study aimed to assess whether pre-treatment imaging parameters from dynamic contrast-enhanced MRI and 18F-fluorodeoxyglucose (18F-FDG) PET/CT are associated with response to neoadjuvant therapy or outcome.

MATERIALS AND METHODS

Following ethical approval and informed consent, prospective participants underwent dynamic contrast-enhanced MRI and 18F-FDG PET/CT prior to neoadjuvant chemotherapy/chemoradiotherapy ± surgery. Vascular dynamic contrast-enhanced MRI and metabolic 18F-FDG PET parameters were compared by tumor characteristics using Mann Whitney U test and with pathological response (Mandard tumor regression grade), recurrence-free and overall survival using logistic regression modelling, adjusting for predefined clinical variables.

RESULTS

39 of 47 recruited participants (30 males; median age 65 years, IQR: 54, 72 years) were included in the final analysis. The tumor vascular-metabolic ratio was higher in patients remaining node positive following neoadjuvant therapy (median tumor peak enhancement/SUVmax ratio: 0.052 vs. 0.023, p = 0.02). In multivariable analysis adjusted for age, gender, pre-treatment tumor and nodal stage, peak enhancement (highest gadolinium concentration value prior to contrast washout) was associated with pathological tumor regression grade. The odds of response decreased by 5% for each 0.01 unit increase (OR 0.95; 95% CI: 0.90, 1.00, p = 0.04). No 18F-FDG PET/CT parameters were predictive of pathological tumor response. No relationships between pre-treatment imaging and survival were identified.

CONCLUSION

Pre-treatment esophagogastric tumor vascular and metabolic parameters may provide additional information in assessing response to neoadjuvant therapy.

Role of Textural Analysis of Pretreatment 18F Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Response Prediction in Esophageal Carcinoma Patients

Introduction

Positron emission tomography/computed tomography (PET/CT) is routinely used for staging, response assessment, and surveillance in esophageal carcinoma patients. The aim of this study was to investigate whether textural features of pretreatment 18F-fluorodeoxyglucose (18F-FDG) PET/CT images can contribute to prognosis prediction in carcinoma oesophagus patients.

Materials and Methods

This is a retrospective study of 30 diagnosed carcinoma esophagus patients. These patients underwent pretreatment 18F-FDG PET/CT for staging. The images were processed in a commercially available textural analysis software. Region of interest was drawn over primary tumor with a 40% threshold and was processed further to derive 92 textural and radiomic parameters. These parameters were then compared between progression group and nonprogression group. The original dataset was subject separately to receiver operating curve analysis. Receiver operating characteristic (ROC) curves were used to identify the cutoff values for textural features with a P < 0.05 for statistical significance. Feature selection was done with principal component analysis. The selected features of each evaluator were subject to 4 machine-learning algorithms. The highest area under the curve (AUC) values was selected for 10 features.

Results

A retrospective study of 30 primary carcinoma esophagus patients was done. Patients were followed up after chemo-radiotherapy and they underwent follow-up PET/CT. On the basis of their response, patients were divided into progression group and nonprogression group. Among them, 15 patients showed disease progression and 15 patients were in the nonprogression group. Ten textural analysis parameters turned out to be significant in the prediction of disease progression. Cutoff values were calculated for these parameters according to the ROC curves, GLZLM_long zone emphasis (Gray Level Zone Length Matrix)_long zone emphasis (44.9), GLZLM_low gray level zone emphasis (0.006), GLZLM_short zone low gray level emphasis (0.0032), GLZLM_long zone low gray level emphasis (0.185), GLRLM_long run emphasis (Gray Level Run Length Matrix) (1.31), GLRLM_low gray level run emphasis (0.0058), GLRLM_short run low gray level emphasis (0.005496), GLRLM_long run low gray level emphasis (0.00727), NGLDM_Busyness (Neighborhood Gray Level Difference Matrix) (0.75), and gray level co-occurrence matrix_homogeneity (0.37). Feature selection by principal components analysis and feature classification by the K-nearest neighbor machine-learning model using independent training and test samples yielded the overall highest AUC.

Conclusions

Textural analysis parameters could provide prognostic information in carcinoma esophagus patients. Larger multicenter studies are needed for better clinical prognostication of these parameters.

Artificial intelligence-assisted esophageal cancer management: Now and future

Esophageal cancer poses diagnostic, therapeutic and economic burdens in high-risk regions. Artificial intelligence (AI) has been developed for diagnosis and outcome prediction using various features, including clinicopathologic, radiologic, and genetic variables, which can achieve inspiring results. One of the most recent tasks of AI is to use state-of-the-art deep learning technique to detect both early esophageal squamous cell carcinoma and esophageal adenocarcinoma in Barrett’s esophagus. In this review, we aim to provide a comprehensive overview of the ways in which AI may help physicians diagnose advanced cancer and make clinical decisions based on predicted outcomes, and combine the endoscopic images to detect precancerous lesions or early cancer. Pertinent studies conducted in recent two years have surged in numbers, with large datasets and external validation from multi-centers, and have partly achieved intriguing results of expert’s performance of AI in real time. Improved pre-trained computer-aided diagnosis algorithms in the future studies with larger training and external validation datasets, aiming at real-time video processing, are imperative to produce a diagnostic efficacy similar to or even superior to experienced endoscopists. Meanwhile, supervised randomized controlled trials in real clinical practice are highly essential for a solid conclusion, which meets patient-centered satisfaction. Notably, ethical and legal issues regarding the black-box nature of computer algorithms should be addressed, for both clinicians and regulators.

The flow-metabolism ratio might predict treatment response and survival in patients with locally advanced esophageal squamous cell carcinoma

Background

Perfusion CT can offer functional information about tumor angiogenesis, and ¹⁸F-FDG PET/CT quantifies the glucose metabolic activity of tumors. This prospective study aims to investigate the value of biologically relevant imaging biomarkers for predicting treatment response and survival outcomes in patients with locally advanced esophageal squamous cell cancer (LA ESCC).

Methods

Twenty-seven patients with pathologically proven ESCC were included. All patients had undergone perfusion CT and ¹⁸F-FDG PET/CT using separate imaging systems before receiving definitive chemoradiotherapy (dCRT). The perfusion parameters included blood flow (BF), blood volume (BV), and time to peak (TTP), and the metabolic parameters included maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG). The flow-metabolism ratio (FMR) was defined as BF divided by SUVmax. Statistical methods used included Spearman’s rank correlation, Mann–Whitney U test or two-sample t test, receiver operating characteristic (ROC) curve analysis, the Kaplan–Meier method, and Cox proportional hazards models.

Results

The median overall survival (OS) and progression-free survival (PFS) were 18 and 11.6 months, respectively. FMR was significantly positively correlated with BF (r = 0.886, p < 0.001) and negatively correlated with SUVmax (r = − 0.547, p = 0.003) and TTP (r = − 0.462, p = 0.015) in the tumors. However, there was no significant correlation between perfusion and PET parameters. After dCRT, 14 patients (51.9%) were identified as responders, and another 13 were nonresponders. The BF and FMR of the responders were significantly higher than those of the nonresponders (42.05 ± 16.47 vs 27.48 ± 8.55, p = 0.007; 3.18 ± 1.15 vs 1.84 ± 0.65, p = 0.001). The ROC curves indicated that the FMR [area under the curve (AUC) = 0.846] was a better biomarker for predicting treatment response than BF (AUC = 0.802). Univariable Cox analysis revealed that of all imaging parameters, only the FMR was significantly correlated with overall survival (OS) (p = 0.015) and progression-free survival (PFS) (p = 0.017). Specifically, patients with a lower FMR had poorer survival. Multivariable analysis showed that after adjusting for age, clinical staging, and treatment response, the FMR remained an independent predictor of OS (p = 0.026) and PFS (p = 0.014).

Conclusions

The flow-metabolism mismatch demonstrated by a low FMR shows good potential in predicting chemoradiotherapy sensitivity and prognosis in ESCC.

Baseline FDG Uptake And Peripheral Lymphocyte-Monocyte Ratio For Predicting Chemoradiotherapy Response In Patients With Esophageal Squamous Cell Carcinoma

Purpose

To explore he predictive values of both the baseline SUVmax of ¹⁸F-fluorodeoxy-glucose by the primary tumor in positron emission tomography/computed tomography (PET/CT) and the lymphocyte-monocyte ratio (LMR) in peripheral blood in inoperable treated esophageal squamous cell carcinoma (ESCC) patients who received concurrent chemoradiotherapy (CCRT).

Patients and methods

Between January 2011 and December 2016, 138 newly diagnosed ESCC patients from our institution were retrospectively recruited. The optimal cut-off values for baseline SUVmax and peripheral LMR were determined by individual receiver operating characteristic curves. The predictive values of baseline SUVmax and peripheral LMR for primary tumor response were examined by chi-square and Fisher’s exact tests, as was their combined predictive value.

Results

The objective response rate (ORR) was significantly different between the high-SUVmax group and the low-SUVmax group (61.9% vs 87.8%; P=0.004), as well as between the high-LMR group and the low-LMR group (80.7% vs 52.0%; P=0.001). Furthermore, the low-SUVmax-high-LMR group achieved the best ORR (100%), which was significantly different from the ORRs of the high-SUVmax-high-LMR group (ORR: 72.1%, P=0.002), the high-SUVmax-low-LMR group (ORR: 45.7%, P=0.001), and the low-SUVmax-low-LMR group (ORR: 45.7%, P=0.001).

Conclusion

Baseline SUVmax of the primary tumor and the peripheral LMR are independent predictors of CCRT response in the primary tumors of ESCC patients. Patients who have lower FDG uptake accompanied by a higher peripheral LMR are more likely to have a better primary tumor response after CCRT.

Morphomic Factors Associated With Complete Response to Neoadjuvant Therapy in Esophageal Carcinoma

BACKGROUND

In patients undergoing neoadjuvant chemoradiotherapy (nCRT) followed by surgery for locally advanced esophageal squamous cell carcinoma (ESCC), patients with a pathologic complete response (pCR) have the greatest benefit. The purpose of this study was to identify morphomic factors obtained from pretreatment computed tomography scans associated with a pCR in ESCC.

METHODS

We retrospectively analyzed patients with ESCC treated with nCRT who underwent esophagectomy between 2006 and 2016. Clinical and morphomic characteristics pre-nCRT were analyzed to identify factors associated with pCR using univariate and multivariable analyses.

RESULTS

There were 183 patients with ESCC included in this study, and 45 (24.6%) patients achieved pCR. The overall survival in patients with pCR was better than that in patients without pCR (5.8 years vs 1.2 years; P < .001). On univariate analysis, increased age, radiation dose greater than or equal to 4000 cGy, and larger subcutaneous adipose tissue area were correlated with pCR. On multivariable logistic regression, increased age (odds ratio, 1.53; P = .03), radiation dose greater than or equal to 4000 cGy (odds ratio, 2.19; P = .04), and larger dorsal muscle group normal-density area (odds ratio, 1.59; P = .03) were independently associated with pCR.

CONCLUSIONS

Increased age, radiation dose greater than or equal to 4000 cGy, and larger dorsal muscle group normal-density area were significantly associated with pCR. These factors may be useful in determining which patients are most likely to benefit from nCRT followed by esophagectomy.

Novel imaging techniques in staging oesophageal cancer

The survival of oesophageal cancer is poor as most patients present with advanced disease. Radiological staging of oesophageal cancer is complex but is fundamental to clinical management. Accurate staging investigations are vitally important to guide treatment decisions and optimise patient outcomes. A combination of baseline computed tomography (CT), endoscopic ultrasound (EUS) and positron emission tomography (PET) are currently used for initial treatment decisions. The potential value of these imaging modalities to re-stage disease, monitor response and alter treatment is currently being investigated. This review presents an essential update on the accuracy of oesophageal cancer staging investigations, their use in re-staging after neo-adjuvant therapy and introduces evolving imaging techniques, including novel biomarkers that have clinical potential in oesophageal cancer.

Clinical implication of the innovations of the 8th edition of the TNM classification for esophageal and esophago-gastric cancer

Epidemiology of esophageal cancer and esophagogastric junction (EGJ) has deeply changed for the past two decades with a dramatically increase of adenocarcinoma whereas squamous cell carcinoma (SCC) has slowly decreased. Moreover, the two histological types differ in a number of features including risks factors, tumor location, tumor biology and outcomes. In acknowledgement of these differences, the newest 8^th edition of the American Joint Committee on Cancer (AJCC) tumor, node and metastasis (TNM) staging classification of epithelial cancers of the esophagus and EGJ has refined this histology-specific disease stage with incorporation of new anatomic and non-anatomic categories. Based on data-driven of patients collected through the Worldwide Esophageal Cancer Collaboration (WECC) group, the 8^th edition database encompasses a six-continent cohort of 22,654 patients among 33 institutions including patients treated with surgery alone and, for the first time, patients treated after neoadjuvant treatment. Anatomic categories include T descriptors (tumor invasion), N descriptors (regional lymph node invasion) and M descriptors (distant site). Non anatomic categories include grade differentiation (G descriptors) and tumor location (L descriptors). Category descriptors are currently assessed by endoscopy with biopsy, by endoscopy ultrasound fine-needle aspiration (EUS-FNA), by thoracic-abdominal-pelvic computed tomography (CT) and whole body flurodeoxyglucose positron emission tomography (FDG-PET) fused with CT. The new 8^th edition considers separate and temporally related cancer classification based on the treatment strategy: clinical cTNM (before any treatment), pathologic pTNM (after surgery alone) and postneoadjuvant pathologic ypTNM (after neoadjuvant treatment followed by surgery). The 8th edition permits a more robust and reliable random forest-based machine learning analysis. Refinement of each T, N, M categories and subcategories makes the 8^th edition more accurate and more adaptable to the current practice including neoadjuvant regimen. The main objective of this review is to examine the current staging of esophageal cancer and the new aspects of the 8^th edition with its applications to clinical practice.

18F-fluorodeoxyglucose positron emission tomography predicts lymph node responses to definitive chemoradiotherapy in esophageal squamous cell carcinoma patients

Purpose

To evaluate the capability of ¹⁸F-fluorodeoxyglucose positron emission tomography/ computed tomography (¹⁸F-FDG-PET/CT) to predict the clinical response of metastatic lymph node (mLN) to definitive chemoradiotherapy (dCRT) and guide personalized radiation dose in esophageal squamous cell carcinoma (ESCC) patients.

Patients and methods

One hundred and forty-three mLNs from 59 patients with ESCC treated with dCRT and who had undergone a pretreatment ¹⁸F-FDG-PET/CT scan were included in the study. All defined mLNs were contoured by nuclear medicine radiologists. Response was evaluated by contrast-enhanced computed tomography and ¹⁸F-FDG-PET/CT.

Results

Sixty-nine mLNs showed complete response (CR), and 74 mLNs showed non-complete response. The 143 mLNs were divided into 4 groups (Groups 1–4) based on the quartiles of maximum standardized uptake value (SUVmax-G1, SUVmax-G2, SUVmax-G3, and SUVmax-G4) and metabolic tumor volume (MTV-G1, MTV-G2, MTV-G3, and MTV-G4). The CR rate of SUVmax-G2 was significantly higher than the other 3 groups. The escalated radiation dose improved the CR rate of lymph nodes in SUVmax-G3 (55 Gy) and SUVmax-G4 (61 Gy). The lowest CR rate was found in MTV-G4 (the group with the largest MTV). The escalated radiation dose (59.7 Gy) improved the CR rate of lymph node in MTV-Groups 3 and 4.

Conclusion

Pretreatment metabolic parameters can predict the response of mLNs to dCRT for patients with ESCC. The parameters could also be used to guide personalized dose to mLNs.

Radiotherapy for esophageal carcinoma: dose, response and survival

Esophageal cancer (EC) is an extremely aggressive, lethal malignancy that is increasing in incidence worldwide. At present, definitive chemoradiotherapy is accepted as the standard treatment for locally advanced EC. The EC guidelines recommend a radiation dose of 50.4 Gy for definitive treatment, yet the outcomes for patients who have received standard-dose radiotherapy remain unsatisfactory. However, some studies indicate that a higher radiation dose could improve local tumor control, and may also confer survival benefits. Some studies, however, suggest that high-dose radiotherapy does not bring survival benefit. The available data show that most failures occurred in the gross target volume (especially in the primary tumor) after definitive chemoradiation. Based on those studies, we hypothesize that at least for some patients, more intense local therapy may lead to better local control and survival. The aim of this review is to evaluate the radiation dose, fractionation strategies, and predictive factors of response to therapy in functional imaging for definitive chemoradiotherapy in esophageal carcinoma, with an emphasis on seeking the predictive model of response to CRT and trying to individualize the radiation dose for EC patients.

18-fluorodeoxy-glucose positron emission computed tomography as predictive of response after chemoradiation in oesophageal cancer patients

INTRODUCTION

The purpose of this study was to evaluate if a baseline, an interim or a post-chemoradiation (CTRT) 18-fluorodeoxy-glucose positron emission computed tomography (18F-FDG PET/CT) studies could provide information on pathologic response to CTRT and overall survival (OS).

MATERIALS AND METHODS

Thirty-one patients with histologically proven adenocarcinoma or squamous cell carcinoma of the oesophagus, fit for trimodality therapy were prospectively enrolled. Most were men (93.5%), and had a stage III cancer (74.2%). Chemotherapy consisted of oxaliplatin/5-fluorouracil (45.2%) and taxane/5-fluorouracil (54.8%). All patients underwent a baseline, an interim (performed 12 ± 2 days after the onset of CTRT) and a post-CTRT 18F-FDG PET/CT study. The 18F-FDG PET/CT variables evaluated were at baseline, interim and post-CTRT studies maximum standardised uptake value (SUV max) and total lesion glycolysis (TLG). Clinical and 18F-FDG PET/CT parameters were correlated with pathologic complete response (pathCR) and OS.

RESULTS

Among the 31 patients studied, 61.3% achieved a clinical complete response (cCR) and 87.1% had surgery. The median OS was 35.1 months (95% confidence interval (CI): 19.9-NA). PathCR rate was 22.2%. There was only a marginal association between cCR and pathCR (p = 0.06). None of the other variables was predictive of pathCR. There was association between OS and baseline TLG (p = 0.03) at the optimal cutoff TLG value of 75.15. Additionally, TLG and ΔTLG post-CTRT were also associated with OS (p = 0.01 and 0.03, respectively).

CONCLUSION

None of the PET parameters is predictive of pathCR but TLG at baseline and post-CTRT are prognostic of OS.

Initial Standardized Uptake Value of Positron Emission Tomography Influences the Prognosis of Patients with Localized Gastric Adenocarcinoma Treated Preoperatively

BACKGROUND

In patients with localized gastric adenocarcinoma (LGAC) who receive preoperative therapy, tools to predict response or prognosticate outcome before therapy are lacking. We used initial standardized uptake value (iSUV) of positron emission tomography (PET) to evaluate its association with overall survival (OS).

METHODS

We identified 60 patients with confirmed LGAC who were treated with preoperative chemoradiation and had a baseline PET in addition to other routine staging. Fisher's exact test and Wilcoxon's rank sum test were used to determine the association between iSUV and other variables, and the log-rank test and Cox proportional hazards model were used for survival analysis.

RESULTS

The median iSUV was 6 (range, 0-28). The presence of signet ring cells in pretreatment biopsies correlated highly with low iSUV (≤ 6; p = 0.0017). Patients with a high iSUV (> 6) had a longer OS compared to those with a low iSUV (≤ 6; p = 0.0344). iSUV was not an independent predictor (p = 0.12); however, the risk of death was reduced for patients with an iSUV > 6 (hazard ratio = 0.26).

CONCLUSION

Our novel findings show that among LGAC patients treated with preoperative chemoradiation and surgery, those with a high iSUV have longer OS than patients with a low iSUV. iSUV appears to have a predictive role in patients with LGAC when treated with preoperative chemoradiation.

Predicting the Response of Neoadjuvant Therapy for Patients with Esophageal Carcinoma: an In-depth Literature Review

Currently, the most promising strategy to improve the prognosis of advanced esophageal cancer is neoadjuvant chemoradiation (CRT) followed by surgery. However, patients who achieved pathological complete response can experience more survival benefit. Therefore, it is critical to identify the responders early in the course of treatment. Published data demonstrate that clinic-histopathological factors, molecular biomarkers, and functional imaging are predictive of neoadjuvant therapy. The existing biomarkers, including epidermal growth factor receptors, angiogenetic factors, transcription factors, tumor suppressor genes, cell cycle regulators, nucleotide excision repair pathway, cytokines, and chemotherapy associated genes, need to be validated and novel biomarkers warrant further exploration. Positron emission tomography (PET) is useful for differentiating the responders of neoadjuvant CRT. The most valuable parameters and the time point of performing PET in the course of treatment remains to be elucidated. Furthermore, predictive models incorporating the multiple categories of factors need to be established with a large, prospective, and homogeneous patient cohort in the future. Standardization of staging, biomarker detection method, and image acquisition protocol will be critical for the generalization of this model. Prospective, multi-center controlled trials, which stratified patients according to these predictive factors, will help guide individualized treatment strategies for patients with esophageal cancer.

Predicting Response to Neoadjuvant Chemotherapy with PET Imaging Using Convolutional Neural Networks

Imaging of cancer with 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) has become a standard component of diagnosis and staging in oncology, and is becoming more important as a quantitative monitor of individual response to therapy. In this article we investigate the challenging problem of predicting a patient's response to neoadjuvant chemotherapy from a single 18F-FDG PET scan taken prior to treatment. We take a "radiomics" approach whereby a large amount of quantitative features is automatically extracted from pretherapy PET images in order to build a comprehensive quantification of the tumor phenotype. While the dominant methodology relies on hand-crafted texture features, we explore the potential of automatically learning low- to high-level features directly from PET scans. We report on a study that compares the performance of two competing radiomics strategies: an approach based on state-of-the-art statistical classifiers using over 100 quantitative imaging descriptors, including texture features as well as standardized uptake values, and a convolutional neural network, 3S-CNN, trained directly from PET scans by taking sets of adjacent intra-tumor slices. Our experimental results, based on a sample of 107 patients with esophageal cancer, provide initial evidence that convolutional neural networks have the potential to extract PET imaging representations that are highly predictive of response to therapy. On this dataset, 3S-CNN achieves an average 80.7% sensitivity and 81.6% specificity in predicting non-responders, and outperforms other competing predictive models.

Pre-Chemoradiotherapy FDG PET/CT cannot Identify Residual Metabolically-Active Volumes within Individual Esophageal Tumors

Objective

To study whether subvolumes with a high pre-chemoradiotherapy (CRT) FDG uptake could identify residual metabolically-active volumes (MAVs) post-CRT within individual esophageal tumors. Accurate identification will allow simultaneous integrated boost to these subvolumes at higher risk to improve clinical outcomes.

Methods

Twenty patients with esophageal cancer were treated with CRT plus surgery and underwent FDG PET/CT scans before and after CRT. The two scans were rigidly registered. Seven MAVs pre-CRT and four MAVs post-CRT within a tumor were defined with various SUV thresholds. The similarity and proximity between the MAVs pre-CRT and post-CRT were quantified with three metrics: fraction of post-CRT MAV included in pre-CRT MAV, volume overlap and centroid distance.

Results

Eight patients had no residual MAV. Six patients had local residual MAV (SUV ≥2.5 post-CRT) within or adjoining the original MAV (SUV ≥2.5 pre-CRT). On average, less than 65% of any post-CRT MAVs was included in any pre-CRT MAVs, with a low volume overlap <45%, and large centroid distance >8.6 mm. In general, subvolumes with higher FDG-uptake pre-CRT or post-CRT had lower volume overlap and larger centroid distance. Six patients had new distant MAVs that were determined to be inflammation from radiation therapy.

Conclusions

Pre-CRT PET/CT cannot reliably identify the residual MAVs within individual esophageal tumors. Simultaneous integrated boost to subvolumes with high FDG uptake pre-CRT may not be feasible.

Spatial-temporal [¹⁸F]FDG-PET features for predicting pathologic response of esophageal cancer to neoadjuvant chemoradiation therapy

PURPOSE

To extract and study comprehensive spatial-temporal (18)F-labeled fluorodeoxyglucose ([(18)F]FDG) positron emission tomography (PET) features for the prediction of pathologic tumor response to neoadjuvant chemoradiation therapy (CRT) in esophageal cancer.

METHODS AND MATERIALS

Twenty patients with esophageal cancer were treated with trimodal therapy (CRT plus surgery) and underwent [(18)F]FDG-PET/CT scans both before (pre-CRT) and after (post-CRT) CRT. The 2 scans were rigidly registered. A tumor volume was semiautomatically delineated using a threshold standardized uptake value (SUV) of ≥2.5, followed by manual editing. Comprehensive features were extracted to characterize SUV intensity distribution, spatial patterns (texture), tumor geometry, and associated changes resulting from CRT. The usefulness of each feature in predicting pathologic tumor response to CRT was evaluated using the area under the receiver operating characteristic curve (AUC) value.

RESULTS

The best traditional response measure was decline in maximum SUV (SUVmax; AUC, 0.76). Two new intensity features, decline in mean SUV (SUVmean) and skewness, and 3 texture features (inertia, correlation, and cluster prominence) were found to be significant predictors with AUC values ≥0.76. According to these features, a tumor was more likely to be a responder when the SUVmean decline was larger, when there were relatively fewer voxels with higher SUV values pre-CRT, or when [(18)F]FDG uptake post-CRT was relatively homogeneous. All of the most accurate predictive features were extracted from the entire tumor rather than from the most active part of the tumor. For SUV intensity features and tumor size features, changes were more predictive than pre- or post-CRT assessment alone.

CONCLUSION

Spatial-temporal [(18)F]FDG-PET features were found to be useful predictors of pathologic tumor response to neoadjuvant CRT in esophageal cancer.

Outcome of trimodality-eligible esophagogastric cancer patients who declined surgery after preoperative chemoradiation

BACKGROUND

For patients with localized esophageal cancer (EC) who can withstand surgery, the preferred therapy is chemoradiation followed by surgery (trimodality). However, after achieving a clinical complete response [clinCR; defined as both post-chemoradiation endoscopic biopsy showing no cancer and physiologic uptake by positron emission tomography (PET)], some patients decline surgery. The literature on the outcome of such patients is sparse.

METHOD

Between 2002 and 2011, we identified 622 trimodality-eligible EC patients in our prospectively maintained databases. All patients had to be trimodality eligible and must have completed preoperative staging after chemoradiation that included repeat endoscopic biopsy and PET among other routine tests.

RESULTS

Out of 622 trimodality-eligible patients identified, 61 patients (9.8%) declined surgery. All 61 patients had a clinCR. The median age was 69 years (range 47-85). Males (85.2%) and Caucasians (88.5%) were dominant. Baseline stage was II (44.2%) or III (52.5%), and histology was adenocarcinoma (65.6%) or squamous cell carcinoma (29.5%). Forty-two patients are alive at a median follow-up of 50.9 months (95% CI 39.5-62.3). The 5-year overall and relapse-free survival rates were 58.1 ± 8.4 and 35.3 ± 7.6%, respectively. Of 13 patients with local recurrence during surveillance, 12 had successful salvage resection.

CONCLUSION

Although the outcome of 61 EC patients with clinCR who declined surgery appears reasonable, in the absence of a validated prediction/prognosis model, surgery must be encouraged for all trimodality-eligible patients.

Accuracy of PET-CT in predicting survival in patients with esophageal cancer

BACKGROUND

Positron emission tomography (PET) is an integral part of tumor staging for patients with esophageal cancer. Recent studies suggest a role for PET scan in predicting survival in these patients, but this relationship is unclear in the setting of neoadjuvant therapy. We examined pretreatment maximum standard uptake value (SUV(max)) of the primary tumor in patients treated with and without neoadjuvant therapy.

METHODS

All patients undergoing esophagectomy with a preoperative PET scan over a nine-year period (2001-2010) were identified from a prospectively maintained database. Positron emission tomography data were obtained from computers housing the original PET scans. Overall survival was correlated with SUV(max) of the primary tumor.

RESULTS

A total of 191 patients were identified, and 103 patients met inclusion criteria. Eighty-two had an adenocarcinoma (80%), and 21 (20%) had a squamous cell carcinoma. Fifty-seven (55%) patients received neoadjuvant therapy. In the surgery alone group, a SUV(max) of > 5.0 in the primary tumor was associated with poor prognosis [Hazard Ratio (HR) 0.32; p = 0.007], but this factor did not retain its significance on multivariate analysis (HR 0.65; p = 0.43). Pretreatment SUV(max) in patients who underwent neoadjuvant therapy was not significant in predicting overall survival (p = 0.10).

CONCLUSIONS

This study does not support the use of SUV(max) on pretreatment PET scans as a prognostic tool for patients with esophageal cancer, especially in those who have received neoadjuvant therapy. Lymph node status is a more accurate predictor of outcome, and efforts to improve pretreatment staging should focus on this factor.

Prognostic significance of SUV on PET/CT in patients with localised oesophagogastric junction cancer receiving neoadjuvant chemotherapy/chemoradiation:a systematic review and meta-analysis

OBJECTIVE

The objective of this study was to comprehensively review the evidence for use of pre-treatment, post-treatment and changes in tumour glucose uptake that were assessed by 18-fludeoxyglucose ((18)F-FDG) positron emission tomography (PET) early, during or immediately after neoadjuvant chemotherapy/chemoradiation to predict prognosis of localised oesophagogastric junction (AEG) cancer.

METHODS

We searched for articles published in English; limited to AEG; (18)F-FDG uptake on PET performed on a dedicated device; dealt with the impact of standard uptake value (SUV) on survival. We extracted an estimate of the log hazard ratios (HRs) and their variances and performed meta-analysis.

RESULTS

798 patients with AEG were included. And the scan time for (18)F-FDG-PET was as follows: prior to therapy (PET1, n=646), exactly 2 weeks after initiation of neoadjuvant therapy (PET2, n=245), and pre-operatively (PET3, n=278). In the two meta-analyses for overall survival, including the studies that dealt with reduction of tumour maximum SUV (SUV(max)) (from PET1 to PET2/PET3 and from PET1 to PET2), the results were similar, with the overall HR for non-responders being 1.83 [95% confidence interval (CI), 1.41-2.36] and 2.62 (95% CI, 1.61-4.26), respectively; as for disease-free survival, the combined HR was 2.92 (95% CI, 2.08-4.10) and 2.39 (95% CI, 1.57-3.64), respectively. The meta-analyses did not attribute significant prognostic values to SUV(max) before and during therapy in localised AEG.

CONCLUSION

Relative changes in FDG-uptake of AEG are better prognosticators. Early metabolic changes from PET1 to PET2 may provide the same accuracy for prediction of treatment outcome as late changes from PET1 to PET3.

New trends for staging and therapy for localized gastroesophageal cancer: the role of PET

Treatment options for localized gastroesophageal cancers reach from limited resection to multimodality treatment. Accurate clinical assessment, prognostic and predictive information are needed to select the most appropriate treatment approach. Positron emission tomography (PET) in combination with computed tomography (CT) in a hybrid imaging modality PET-CT may refine the staging accuracy and add prognostic information. Moreover, experiences from diverse centers indicate that PET also might improve significantly the assessment of response to preoperative chemotherapy and chemoradiotherapy. This article outlines the current value of PET in the staging and multidisciplinary care of gastroesophageal cancer. At this stage, it remains unclear whether the prognosis of patients can be improved by implementing PET in the management of localized disease. Prospective multicenter studies have to be carried out to validate metabolic cut-off values and to prove the benefit of PET-guided treatment decisions.

Barrett's esophagus: treatments of adenocarcinomas II

The following topics are explored in this collection of commentaries on treatments of adenocarcinomas related to Barrett's esophagus: the importance of intraoperative frozen sections of the margins for the detection of high dysplasia; the preferable way for sentinel node dissection; the current role of robotic surgery and of video-endoscopic approach; the value of the Siewert's classification of adenocarcinomas; the indications of two-step esophagectomy; the evaluation of pathological complete response; the role of PET scan in staging and response assessment; the role of p53 in the selection of adenocarcinomas patients; chemotherapy regimens for adenocarcinomas; the use of monoclonal antibodies in the control of cell proliferation; he attempt to define a stage-specific strategy, and the possible indications of selective therapy; and changes in mortality rates from esophageal cancer.

Sequential FDG-PET and induction chemotherapy in locally advanced adenocarcinoma of the Oesophago-gastric junction (AEG): the Heidelberg Imaging program in Cancer of the oesophago-gastric junction during Neoadjuvant treatment: HICON trial

Background

18-Fluorodeoxyglucose-PET (¹⁸F-FDG-PET) can be used for early response assessment in patients with locally advanced adenocarcinomas of the oesophagogastric junction (AEG) undergoing neoadjuvant chemotherapy. It has been recently shown in the MUNICON trials that response-guided treatment algorithms based on early changes of the FDG tumor uptake detected by PET are feasible and that they can be implemented into clinical practice.

Only 40%-50% of the patients respond metabolically to therapy. As metabolic non-response is known to be associated with a dismal prognosis, metabolic non-responders are increasingly treated with alternative neoadjuvant chemotherapies or chemoradiation in order to improve their clinical outcome. We plan to investigate whether PET can be used as response assessment during radiochemotherapy given as salvage treatment in early metabolic non-responders to standard chemotherapy.

Methods/Design

The HICON trial is a prospective, non-randomized, explorative imaging study evaluating the value of PET as a predictor of histopathological response in metabolic non-responders. Patients with resectable AEG type I and II according to Siewerts classification, staged cT3/4 and/or cN+ and cM0 by endoscopic ultrasound, spiral CT or MRI and FDG-PET are eligible. Tumors must be potentially R0 resectable and must have a sufficient FDG-baseline uptake. Only metabolic non-responders, showing a < 35% decrease of SUV two weeks after the start of neoadjuvant chemotherapy are eligible for the study and are taken to intensified taxane-based RCT (chemoradiotherapy (45 Gy) before surgery. ¹⁸FDG-PET scans will be performed before ( = Baseline) and after 14 days of standard neoadjuvant therapy as well as after the first cycle of salvage docetaxel/cisplatin chemotherapy (PET 1) and at the end of radiochemotherapy (PET2). Tracer uptake will be assessed semiquantitatively using standardized uptake values (SUV). The percentage difference ΔSUV = 100 (SUV_Baseline - SUV _PET1)/SUV_Baseline will be calculated and assessed as an early predictor of histopathological response. In a secondary analysis, the association between the difference SUV_PET1 - SUV_PET2 and histopathological response will be evaluated.

Discussion

The aim of this study is to investigate the potential of sequential ¹⁸FDG-PET in predicting histopathological response in AEG tumors to salvage neoadjuvant radiochemotherapy in patients who do not show metabolic response to standard neoadjuvant chemotherapy.

Trial Registration

Clinical trial identifier NCT01271322

Prognostic significance of baseline positron emission tomography and importance of clinical complete response in patients with esophageal or gastroesophageal junction cancer treated with definitive chemoradiotherapy

BACKGROUND

Metabolic imaging is of interest in esophageal cancer; however, the usefulness of initial standardized uptake value (SUV) in positron emission tomography (PET) is unknown in patients with esophageal or gastroesophageal carcinoma treated with definitive chemoradiotherapy. The authors hypothesized that initial SUV would correlate with patient outcome.

METHODS

The authors retrospectively analyzed esophageal or gastroesophageal carcinoma patients who had baseline PET and endoscopic ultrasonography in addition to other routine staging. All patients received definitive chemoradiotherapy. Multiple statistical methods were used.

RESULTS

The authors analyzed 209 consecutive esophageal or gastroesophageal carcinoma patients treated with definitive chemoradiation for outcome; of these, 180 had baseline PET for additional analyses. The median overall survival (OS) for all patients was 20.7 months (95% confidence interval, 18.8-26.3). Patients with clinical complete response (CR) lived longer than those with less than clinical CR (P < .0001). The median initial SUV was 12.7 (range, 0-51). Higher initial SUV was associated with longer tumors (P = .0001), higher T-stage status (P < .0001), positive N-stage status (P = .0001), higher overall stage (P < .0001), lack of clinical CR (P = .0002), and squamous cell histology (P < .0001). In the univariate analysis, initial SUV was associated with OS (Cox model, P = .016; log-rank test, P = .002). In the multivariate analysis, initial SUV dichotomized by the median value (P = .024) and tumor grade (P = .016) proved to be independent OS prognosticators. Median initial SUV for clinical CR patients was 10.2, compared with 15.3 for less than clinical CR patients (P = .0058).

CONCLUSIONS

The data indicate that a higher initial SUV is associated with poorer OS in patients with esophageal or gastroesophageal carcinoma receiving definitive chemoradiation. Upon validation, baseline PET may become a useful stratification factor in randomized trials and for individualizing therapy.

Intratumor heterogeneity characterized by textural features on baseline 18F-FDG PET images predicts response to concomitant radiochemotherapy in esophageal cancer

(18)F-FDG PET is often used in clinical routine for diagnosis, staging, and response to therapy assessment or prediction. The standardized uptake value (SUV) in the primary or regional area is the most common quantitative measurement derived from PET images used for those purposes. The aim of this study was to propose and evaluate new parameters obtained by textural analysis of baseline PET scans for the prediction of therapy response in esophageal cancer.

METHODS

Forty-one patients with newly diagnosed esophageal cancer treated with combined radiochemotherapy were included in this study. All patients underwent pretreatment whole-body (18)F-FDG PET. Patients were treated with radiotherapy and alkylatinlike agents (5-fluorouracil-cisplatin or 5-fluorouracil-carboplatin). Patients were classified as nonresponders (progressive or stable disease), partial responders, or complete responders according to the Response Evaluation Criteria in Solid Tumors. Different image-derived indices obtained from the pretreatment PET tumor images were considered. These included usual indices such as maximum SUV, peak SUV, and mean SUV and a total of 38 features (such as entropy, size, and magnitude of local and global heterogeneous and homogeneous tumor regions) extracted from the 5 different textures considered. The capacity of each parameter to classify patients with respect to response to therapy was assessed using the Kruskal-Wallis test (P < 0.05). Specificity and sensitivity (including 95% confidence intervals) for each of the studied parameters were derived using receiver-operating-characteristic curves.

RESULTS

Relationships between pairs of voxels, characterizing local tumor metabolic nonuniformities, were able to significantly differentiate all 3 patient groups (P < 0.0006). Regional measures of tumor characteristics, such as size of nonuniform metabolic regions and corresponding intensity nonuniformities within these regions, were also significant factors for prediction of response to therapy (P = 0.0002). Receiver-operating-characteristic curve analysis showed that tumor textural analysis can provide nonresponder, partial-responder, and complete-responder patient identification with higher sensitivity (76%-92%) than any SUV measurement.

CONCLUSION

Textural features of tumor metabolic distribution extracted from baseline (18)F-FDG PET images allow for the best stratification of esophageal carcinoma patients in the context of therapy-response prediction.

Prediction of tumor response to neoadjuvant therapy in patients with esophageal cancer with use of 18F FDG PET: a systematic review

PURPOSE

To systematically review the accuracy of fluorine 18 ((18)F) fluorodeoxyglucose (FDG) positron emission tomography (PET) in the prediction of tumor response to neoadjuvant therapy in patients with esophageal cancer.

MATERIALS AND METHODS

The MEDLINE and EMBASE databases were systematically searched for relevant studies. Methodologic quality of the included studies was assessed. Sensitivities and specificities of (18)F FDG PET in individual studies were calculated and underwent meta-analysis with a random effects model. A summary receiver operating characteristic curve (sROC) was constructed with the Moses-Shapiro-Littenberg method. A chi(2) test was performed to test for heterogeneity (defined as P < .10). Potential sources for heterogeneity were explored by assessing whether certain covariates significantly (P < .05) influenced the relative diagnostic odds ratio.

RESULTS

Twenty reports, comprising a total of 849 patients with esophageal cancer, were included. Overall, the studies were of moderate methodologic quality. Sensitivity and specificity of (18)F FDG PET ranged from 33% to 100% and from 30% to 100%, respectively, with pooled estimates of 67% (95% confidence interval: 62%, 72%) and 68% (95% confidence interval: 64%, 73%), respectively. The area under the sROC curve was 0.7815. There was significant heterogeneity in both the sensitivity and specificity of the included studies (P < .0001). Spearman rho between the logit of sensitivity and the logit of 1-specificity was 0.086 (P = .719), which suggested that there was no threshold effect. Studies performed outside of the United States and studies of higher methodologic quality yielded significantly higher overall accuracy.

CONCLUSION

On the basis of current evidence, (18)F FDG PET should not yet be used in routine clinical practice to guide neoadjuvant therapy decisions in patients with esophageal cancer.

SUPPLEMENTAL MATERIAL

http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.09091324/-/DC1.