Lack of fludeoxyglucose F 18 uptake in posttreatment positron emission tomography as a significant predictor of survival after subsequent surgery in multimodality treatment for patients with locally advanced esophageal squamous cell carcinoma

Novel Advances in Qualitative Diagnostic Imaging for Decision Making in Multidisciplinary Treatment for Advanced Esophageal Cancer

Background: Recently, neoadjuvant therapy and the succeeding surgery for advanced esophageal cancer have been evaluated. In particular, the response to the therapy has been found to affect surgical outcomes, and thus a precise evaluation of treatment effect is important for this strategy. In this study, articles on qualitative diagnostic modalities to evaluate tumor activities were reviewed, and the diagnostic indices were examined. Methods: For prediction of the effect, perfusion CT and diffusion MRI were estimated. For the histological response evaluation, perfusion CT, diffusion-MRI, and FDG-PET were estimated. For downstaging evaluation of T4, tissue-selective image reconstruction using enhanced CT was estimated and diagnostic indices were reviewed. Results: The prediction of the effect using perfusion CT with 'pre CRT blood flow' and diffusion MRI with 'pre CRT ADC value'; the estimation of the histological response using perfusion CT with 'post CRT blood flow reduction, using diffusion MRI with 'post CRT ADC increasing', and using FDG-PET with 'post CRT SUV reduction'; and the downstaging evaluation of T4 using CT image reconstruction with 'fibrous changed layer' were performed well, respectively. Conclusions: Qualitative imaging modalities for prediction or response evaluation of neoadjuvant therapy for progressive esophageal cancer were useful for the decision making of the treatment strategy of the multidisciplinary treatment.

Blood biomarkers as predictors of pathological lymph node metastasis in clinical stage T1N0 esophageal squamous cell carcinoma

Accurate preoperative evaluation of lymph node (LN) metastasis is important for determining the treatment strategy for superficial esophageal cancer. Blood biomarkers, such as the neutrophil-lymphocyte, platelet-lymphocyte, and lymphocyte-monocyte ratios (NLR, PLR, and LMR, respectively), have clinical applications as predictors of LN metastasis for different cancers. Here, we investigated the use of these ratios as predictors of pathological LN metastasis and prognosis in patients with clinical stage T1N0M0 esophageal squamous cell carcinoma (ESCC). Patients (n = 185) with cT1N0M0 ESCC who underwent esophagectomy with R0 resection between April 2003 and August 2021 were enrolled. We investigated the ability of pretreatment NLR, PLR, and LMR to predict pathological LN metastasis. The optimal cutoff values of NLR, PLR, and LMR to predict pathological LN metastasis were 2.1, 122, and 4.8, respectively. Univariate and multivariate analyses revealed that the primary tumor length, depth of invasion, and NLR were significant predictors of LN metastasis. Furthermore, similar to the 5-year overall survival, the 5-year relapse-free survival was significantly better in the low NLR group than in the high NLR group. The NLR was the most useful predictor of pathological LN metastasis. Patients diagnosed with clinical stage I ESCC and with a high NLR require adequate LN dissection and may be good candidates for preoperative adjuvant therapy.

Unresected small lymph node assessment predicts prognosis for patients with pT3N0M0 thoracic esophageal squamous cell carcinoma

Background

The role of unresected small lymph nodes (LNs) which may contain metastases for thoracic esophageal squamous cell carcinoma (TESCC) has not been addressed. The aim of the study was to investigate the role of unresected small LNs assessment using computed tomography (CT) in prognostic estimates of pT3N0M0 TESCC patients.

Methods

Between January 2009 and December 2017, 294 patients who underwent esophagectomy with R0 resection at Sichuan Cancer Hospital were retrospectively examined, and the last follow-up time was July 2018. Patients were classified into CT-suspect and CT-negative groups according to the shortest diameter and the shape (axial ratio) of the unresected small LNs on preoperative CT. The Kaplan–Meier method was used to compare survival differences in prognostic factors. Univariate and multivariate analyses were performed to identify prognostic factors for survival and recurrence.

Results

Eighty-four patients (28.6%) were classified as CT-suspect group according to the diagnostic criteria; survival analysis suggested that CT-suspect group of patients had a relatively poorer prognosis (P<0.05). Cox regression analysis indicated that unresected small LNs status, tumor grade, and postoperative adjuvant therapy were independent prognostic factors for patients with pT3N0M0 TESCC (P<0.05). Further analysis shown the rates of total recurrence (TR) and locoregional recurrence (LR) in the CT-suspect group were significantly higher than that in the CT-negative group (TR, P<0.001; LR, P<0.001). Among the LRs, the rate of supraclavicular lymph node recurrence in the CT-suspect group was significantly higher than that in the CT-negative group (P<0.001).

Conclusions

Unresected small lymph node assessment is critically important and predict prognosis for pT3N0M0 TESCC patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12957-021-02412-1.

PET Imaging and Rate of Pathologic Complete Response in Esophageal Squamous Cell Carcinoma

BACKGROUND

For locally advanced esophageal squamous cell carcinoma (ESCC), chemoradiation (ChemoRT) followed by surgery offers the best chance of cure, with a 35-50% pathologic complete response (pCR) rate. Given the morbidity of esophagectomy and the possibility of pCR with ChemoRT, a 'watch and wait' strategy has been proposed, particularly for squamous cell carcinoma. The ability to accurately predict which patients will have pCR from ChemoRT is critical in treatment decision making. This study assessed positron emission tomography (PET) in predicting pCR after neoadjuvant ChemoRT for ESCC.

METHODS

ESCC patients treated with ChemoRT followed by surgery were identified. Maximum standard uptake value (SUV), metabolic tumor volume, total lesion glycolysis, and first-order textual features of standard deviation, kurtosis and skewness were measured from PET. Univariable and multivariable generalized linear method analyses were performed. A metabolic complete response (mCR) was defined as a post-therapy PET scan with maximum SUV < 4.0.

RESULTS

Twenty-seven patients underwent ChemoRT followed by surgery, with overall pCR seen in 11 (41%) patients and radiographic mCR seen in 12 (44%) patients. Final pathology for these 12 patients revealed pCR (ypT0N0M0) in 5 (42%) patients and persistent disease in 7 (58%) patients. Univariate analysis did not reveal PET parameters predictive of pCR.

CONCLUSION

Treatment of ESCC with ChemoRT often results in a robust clinical response. Among patients with an mCR after ChemoRT, disease persistence was found in 58%. The inability of PET to predict pCR is important in the context of a 'watch and wait' strategy for ESCC treated with ChemoRT.

Metabolic and Immunological Subtypes of Esophageal Cancer Reveal Potential Therapeutic Opportunities

Background

Esophageal cancer has the sixth highest rate of cancer-associated deaths worldwide, with many patients displaying metastases and chemotherapy resistance. We sought to find subtypes to see if precision medicine could play a role in finding new potential targets and predicting responses to therapy. Since metabolism not only drives cancers but also serves as a readout, metabolism was examined as a key reporter for differences.

Methods

Unsupervised and supervised classification methods, including hierarchical clustering, partial least squares discriminant analysis, k-nearest neighbors, and machine learning techniques, were used to discover and display two major subgroups. Genes, pathways, gene ontologies, survival, and immune differences between the groups were further examined, along with biomarkers between the groups and against normal tissue.

Results

Esophageal cancer had two major unique metabolic profiles observed between the histological subtypes esophageal squamous cell carcinoma (ESCC) and esophageal adenocarcinoma (EAC). The metabolic differences suggest that ESCC depends on glycolysis, whereas EAC relies more on oxidative metabolism, catabolism of glycolipids, the tricarboxylic acid (TCA) cycle, and the electron transport chain. We also noted a robust prognostic risk associated with COQ3 expression. In addition to the metabolic alterations, we noted significant alterations in key pathways regulating immunity, including alterations in cytokines and predicted immune infiltration. ESCC appears to have increased signature associated with dendritic cells, Th17, and CD8 T cells, the latter of which correlate with survival in ESCC. We bioinformatically observed that ESCC may be more responsive to checkpoint inhibitor therapy than EAC and postulate targets to enhance therapy further. Lastly, we highlight correlations between differentially expressed enzymes and the potential immune status.

Conclusion

Overall, these results highlight the extreme differences observed between the histological subtypes and may lead to novel biomarkers, therapeutic strategies, and differences in therapeutic response for targeting each esophageal cancer subtype.

18F-FDG PET/CT Parameters for Predicting Prognosis in Esophageal Cancer Patients Treated With Concurrent Chemoradiotherapy

Background and Aims:

This study evaluated the prognostic value of ¹⁸F-fluorodeoxyglucose positron emission tomography with integrated computed tomography (¹⁸F-FDG PET/CT) performed before and after concurrent chemoradiotherapy (CCRT) in esophageal cancer.

Methods:

We analyzed the prognosis of 50 non-metastatic squamous cell esophageal cancer (T1-4N0-2) patients who underwent CCRT with curative intent at Inje University Busan Paik Hospital and Haeundae Paik Hospital from 2009 to 2019. Median total radiation dose was 54 Gy (range 34-66 Gy). Our aim was to investigate the relationship between PET/CT values and prognosis. The primary end point was progression-free survival (PFS).

Results:

The median follow-up period was 9.9 months (range 1.7-85.7). Median baseline maximum standard uptake value (SUVmax) was 14.2 (range 3.2-27.7). After treatment, 29 patients (58%) showed disease progression. The 3-year PFS and overall survival (OS) were 24.2% and 54.5%, respectively. PFS was significantly lower (P = 0.015) when SUVmax of initial PET/CT exceeded 10 (n = 22). However, OS did not reach a significant difference based on maximum SUV (P = 0.282). Small metabolic tumor volume (≤14.1) was related with good PFS (P = 0.002) and OS (P = 0.001). Small total lesion of glycolysis (≤107.3) also had a significant good prognostic effect on PFS (P = 0.009) and OS (P = 0.025). In a subgroup analysis of 18 patients with follow-up PET/CT, the patients with SUV max ≤3.5 in follow-up PET/CT showed longer PFS (P = 0.028) than those with a maximum SUV >3.5.

Conclusion:

Maximum SUV of PET/CT is useful in predicting prognosis of esophageal cancer patients treated with CCRT. Efforts to find more effective treatments for patients at high risk of progression are still warranted.

Meta-analysis of prognostic factors of overall survival in patients undergoing oesophagectomy for oesophageal cancer

INTRODUCTION

Currently, the American Joint Commission on Cancer (AJCC) staging system is used for prognostication for oesophageal cancer. However, several prognostically important factors have been reported but not incorporated. This meta-analysis aimed to characterize the impact of preoperative, operative, and oncological factors on the prognosis of patients undergoing curative resection for oesophageal cancer.

METHODS

This systematic review was performed according to PRISMA guidelines and eligible studies were identified through a search of PubMed, Scopus, and Cochrane CENTRAL databases up to 31 December 2018. A meta-analysis was conducted with the use of random-effects modeling to determine pooled univariable hazard ratios (HRs). The study was prospectively registered with the PROSPERO database (Registration: CRD42018157966).

RESULTS

One-hundred and seventy-one articles including 73,629 patients were assessed quantitatively. Of the 122 factors associated with survival, 39 were significant on pooled analysis. Of these. the strongly associated prognostic factors were 'pathological' T stage (HR: 2.07, CI95%: 1.77-2.43, P < 0.001), 'pathological' N stage (HR: 2.24, CI95%: 1.95-2.59, P < 0.001), perineural invasion (HR: 1.54, CI95%: 1.36-1.74, P < 0.001), circumferential resection margin (HR: 2.17, CI95%: 1.82-2.59, P < 0.001), poor tumor grade (HR: 1.53, CI95%: 1.34-1.74, P < 0.001), and high neutrophil:lymphocyte ratio (HR: 1.47, CI95%: 1.30-1.66, P < 0.001).

CONCLUSION

Several tumor biological variables not included in the AJCC 8th edition classification can impact on overall survival. Incorporation and validation of these factors into prognostic models and next edition of the AJCC system will enable personalized approach to prognostication and treatment.

Utility of positron emission-computed tomography for predicting pathological response in resectable oesophageal squamous cell carcinoma after neoadjuvant chemoradiation

OBJECTIVES

For patients with locally advanced oesophageal cancer, improved complete pathological response after neoadjuvant chemoradiation (nCRT) and the detrimental effects on the quality of life related to oesophagectomy have led to the need for a reliable method to select patients who have achieved complete pathological response and do not need surgery. The reliability of 18F-fluorodeoxyglucose positron emission-computed tomography (PET-CT) for predicting the pathological response after nCRT was evaluated.

METHODS

Patients with locally advanced oesophageal cancer who were treated with nCRT and oesophagectomy from July 2010 to February 2017 were analysed. On the post-nCRT PET-CT, a complete metabolic response was defined as all tumourous lesions demonstrating maximum standardized uptake value (SUVmax) ≤2.5. To minimize the effect of radiation-induced oesophagitis, complete metabolic response was also defined as no viable lesion distinguishable from the background with diffuse uptake. The sensitivity, specificity, positive predictive value and negative predictive value were analysed for SUVmax, [X]ΔSUVmax and %ΔSUVmax.

RESULTS

A total of 158 patients with oesophageal squamous cell carcinoma were analysed. The rate of complete pathological response was 27.8%, and that of complete metabolic response was 7.6%. The sensitivity, specificity, positive predictive value and negative predictive value based on SUVmax ≤2.5 and visual normalization were 95%, 14%, 74% and 50%, respectively. Analysis for [X]ΔSUVmax and %ΔSUVmax using the optimal cut-off values determined by the receiver operating characteristic curves did not show an improved predictive efficacy.

CONCLUSIONS

PET-CT is not a reliable tool for predicting pathological response. Patients diagnosed with resectable oesophageal cancer who underwent neoadjuvant therapy should not be exempt from surgery based on PET-CT results.

Evaluation of metastatic lymph nodes in cN0 thoracic esophageal cancer patients with inconsistent pathological lymph node diagnosis

BACKGROUND

Preoperative clinical diagnosis of lymph node (LN) metastasis and subsequent pathological diagnosis are often not in agreement. Detection of false-negative LNs is essential in selecting an optimal treatment strategy, and most importantly, the presence of false-negative LN is itself a significant prognostic indicator. Therefore, at present, there is an urgent need to establish more accurate and individualized evaluation methods for LN metastasis.

METHODS

Of 213 cN0 patients who underwent curative esophagectomy without preoperative neoadjuvant treatment, 60 (28%) had LN metastasis diagnosed pathologically. There were 129 false-negative LNs, of which 85 were detectable by preoperative computed tomography (CT). We retrospectively investigated the distribution, frequency, and characteristics of pathologically positive nodes in patients with clinically N0 esophageal cancer.

RESULTS

The paracardial region was the most frequent region of false-negative LNs, accounting for 26% (22 LNs) of the total incidence. False-negative LNs distributed widely from the neck to the abdomen in patients with a primary tumor in the middle thoracic esophagus. In patients with a primary tumor in the lower thoracic esophagus, four false-negative LNs were detected in the superior mediastinum. When the short-axis diameter, shape, and attenuation patterns of the LNs were used as criteria for metastasis diagnosis, they were insufficient for an accurate diagnosis. However, false-negative LNs in the most frequently occurring sites are characterized by smaller short-axis, suggesting that accurate diagnosis cannot be made unless the diagnostic criteria for the short-axis are reduced in addition to shape and attenuation.

CONCLUSIONS

Although restrictive to the most frequent regions of false-negative LNs occur, reducing size criterion and consideration of their shape and attenuation may contribute to improved diagnosis.

Detecting Pathological Complete Response in Esophageal Cancer after Neoadjuvant Therapy Based on Imaging Techniques: A Diagnostic Systematic Review and Meta-Analysis

INTRODUCTION

Up to 32% of patients with esophageal cancer show a pathological complete response (ypCR) after neoadjuvant therapy. To prevent overtreatment, the indication to perform esophagectomy in these patients should be reconsidered. Implementing an organ-preserving strategy for patients with ypCR requires an accurate assessment of residual disease after neoadjuvant treatment. The aim of this study was to systematically review the effectiveness of imaging techniques used for detection of ypCR after neoadjuvant therapy but before resection in patients with esophageal cancer.

METHODS

A systematic literature search of the Medline, Embase, and Cochrane Library databases was performed from January 1, 2000, to December 13, 2017. Eligible studies were diagnostic studies that compared results of imaging modalities after neoadjuvant therapy to histopathological findings in the resection specimen after esophagectomy. Methodological quality was assessed by the Cochrane Quality Assessment of Diagnostic Accuracy Studies, version 2, model. Primary outcome measures were true positive, false-positive, false-negative, and true negative values of imaging techniques predicting ypCR. A meta-analysis was performed by pooling sensitivities and specificities by using a bivariate model.

RESULTS

A total of 4420 articles were identified. After exclusion of irrelevant titles and abstracts, 360 articles were reviewed in full text. In total, four imaging modalities (computed tomography [CT], positron emission tomography [PET-CT], endoscopic ultrasound [EUS], and magnetic resonance imaging [MRI]) were used for restaging. The meta-analysis was conducted with data from 56 studies involving 3625 patients. The pooled sensitivities of CT, PET-CT, EUS, and MRI for detecting ypCR were 0.35, 0.62, 0.01 and 0.80, respectively, whereas the pooled specificities were 0.83, 0.73, 0.99, and 0.83, respectively. The positive predictive value in detecting ypCR was 0.47 for CT, 0.41 for PET-CT, not applicable for EUS, and 0.61 for MRI.

CONCLUSION

Current imaging modalities such as CT, PET-CT, and EUS seem to be insufficiently accurate to identify complete responders. More accurate diagnostic tests are needed to improve restaging accuracy for patients with esophageal cancer.

Imaging biomarkers for the treatment of esophageal cancer

Esophageal cancer is known as one of the malignant cancers with poor prognosis. To improve the outcome, combined multimodality treatment is attempted. On the other hand, advances in genomics and other “omic” technologies are paving way to the patient-oriented treatment called “personalized” or “precision” medicine. Recent advancements of imaging techniques such as functional imaging make it possible to use imaging features as biomarker for diagnosis, treatment response, and prognosis in cancer treatment. In this review, we will discuss how we can use imaging derived tumor features as biomarker for the treatment of esophageal cancer.

Metabolic parameters of sequential 18F-FDG PET/CT predict overall survival of esophageal cancer patients treated with (chemo-) radiation

BACKGROUND

To evaluate the prognostic value of metabolic parameters of pre-treatment and interim 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) for overall survival (OS) of esophageal cancer(EC) patients undergoing (chemo-) radiotherapy.

METHODS

A retrospective analysis of 134 patients with pathology confirmed squamous cell EC treated between July 2009 and October 2013 in our hospital was performed. Inclusion criteria for this study were curative intended radiotherapy and availability of pre-treatment and interim 18F-FDG PET. 18F-FDG PET/CT scans were acquired before treatment and after 40 Gray (Gy) of radiotherapy. Maximum standard uptake value (SUV_max), metabolic tumor volume(MTV), total lesion glycolysis (TLG), and the percentual changes during both PET scans were recorded. The parameters were named as SUVmax1,MTV1,TLG1,SUVmax2,MTV2,TLG2,△SUV_max,△MTV and △TLG. The receiver operating characteristic curve (ROC) was used to analyze the relationship between metabolic parameters and OS, survival analysis was carried out by Kaplan-Meier and Cox regression analysis.

RESULTS

Univariate survival analysis showed that SUVmax2、MTV1、△MTV、TLG1、TLG2 and △TLG were associated with OS. Based on the largest Youden index of ROC curves, patients with SUVmax2 < 7.8, MTV1 < 10.5, △MTV < 0.075, TLG1 < 59.8, TLG2 < 44.3 and △TLG < 0.27 tended to live longer. Stratified for these parameters, the estimated median survival time were 27.9 months (m) vs 9.8 m, 36.9 m vs 11.3 m, 41.6 m vs 12 m, 48.9 m vs 14.3 m, 32.6 m vs 13.2 m, and 41.6 m vs 14.5 m. Cox multi-factor regression analyses revealed SUV_max2 as an independent prognostic factor for OS complementary to TNM staging and the length of primary tumor.

CONCLUSIONS

Sequential 18F-FDG PET/CT metabolic parameters bear important prognostic value for OS of EC patients. 18F-FDG PET/CT scan before treatment and during chemoradiotherapy seems helpful to evaluate the effect of chemoradiotherapy, guide clinical decisions and provide patients with personalized treatment.

Post-chemoradiotherapy FDG PET with qualitative interpretation criteria for outcome stratification in esophageal squamous cell carcinoma

Objectives

Post-chemoradiotherapy (CRT) FDG PET is a useful prognosticator of esophageal cancer. However, debate on the diverse criteria of previous publications preclude worldwide multicenter comparisons, and even a universal practice guide. We aimed to validate a simple qualitative interpretation criterion of post-CRT FDG PET for outcome stratification and compare it with other criteria.

Methods

The post-CRT FDG PET of 114 patients with esophageal squamous cell carcinoma (ESCC) were independently interpreted using a qualitative 4-point scale (Qual_4PS) that identified focal esophageal FDG uptake greater than liver uptake as residual tumor. Cohen’s κ coefficient (κ) was used to measure interobserver agreement of Qual_4PS. The Kaplan-Meier method and Cox proportional hazards regression analyses were used for survival analysis. Other criteria included a different qualitative approach (Qual_BK), maximal standardized uptake values (SUV_max3.4, SUV_max2.5), relative change of SUV_max between pre- and post-CRT FDG PET (ΔSUV_max), mean standardized uptake values (SUV_mean), metabolic volume (MV) and total lesion glycolysis (TLG).

Results

Overall interobserver agreement on the Qual_4PS criterion was excellent (κ: 0.95). Except the Qual_BK, SUV_max2.5, and TLG, all the other criteria were significant predictors for overall survival (OS). Multivariable analysis showed only Qual_4PS (HR: 15.41; P = 0.005) and AJCC stage (HR: 2.47; P = 0.007) were significant independent variables. The 2-year OS rates of Qual_4PS(‒) patients undergoing CRT alone (68.4%) and patients undergoing trimodality therapy (62.5%) were not significant different, but the 2-year OS rates of Qual_4PS(+) patients undergoing CRT alone (10.0%) were significantly lower than in patients undergoing trimodality therapy (42.1%).

Conclusions

The Qual_4PS criterion is reproducible for assessing the response of ESCC to CRT, and valuable for predicting survival. It may add value to response-adapted treatment for ESCC patients, and help to decide whether surgery is warranted after CRT.

Baseline 18F-FDG PET/CT as predictor of the pathological response to neoadjuvant therapy in esophageal cancer: A retrospective study

The type of pathological response to neoadjuvant chemoradiation in patients with locally advanced esophageal cancer predicts overall survival (OS).We aimed to assess early 18F-FDG positron emission tomography/computed tomography parameters in predicting the pathological response to neoadjuvant treatment.The cohort included consecutive patients with locally advanced esophageal cancer who underwent baseline 18F-FDG positron emission tomography/computed tomography between September 2006 and February 2015. Positron emission tomography variables of maximum and average standardized uptake values (SUVmax, SUVaverage), metabolic tumor volume (MTV), and total lesion glycolysis were recorded in addition to computed tomography volume. MTV was calculated using cut-off values of 42%, 50% and 60% (MTV 0.42, 0.5, and 0.6) of the tumoral SUVmax. Receiver operating characteristic (ROC) analysis was used to determine sensitivity and specificity.Sixty-one patients (44 male, 17 female) fulfilled the inclusion criteria. Only MTV values of 13.6 mL (MTV 0.42) and 7.4 mL (MTV 0.5) remained significant on ROC analysis, with an area under the curve of 0.690 (confidence interval 0.557-0.823, p = .02] and 0.664 (confidence interval 0.527-0.802, P = .048), respectively in differentiating patients with a complete (n = 44) or incomplete (n = 17) pathological response.MTV at presentation is associated with the pathological response to neoadjuvant chemoradiation in patients with locally advanced esophageal cancer.

18F-fluorodeoxyglucose positron emission tomography/computed tomography for the prediction of survival in patients with advanced esophageal cancer who have undergone neoadjuvant chemotherapy

Neoadjuvant chemotherapy (NAC) is a promising treatment strategy for advanced esophageal cancer. However, measures of NAC response assessment and prognostic prediction have not yet been established. The aim of this study was to evaluate the usefulness of combined ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT). A total of 77 patients with stage IB-IV esophageal cancer who were treated with NAC followed by curative resection were retrospectively analyzed. PET/CT was performed before and after NAC and 56 patients were clinical responders. The pretreatment maximal standardized uptake value (pre-SUV_max), post-SUV_max and %SUV_max were 11.3±5.8, 5.1±4.8 and 49.0±35.1%, respectively, for the main tumors (T) and 4.3±2.8, 2.5±1.9 and 67.0±39.6%, respectively, for the metastatic nodes (N). Among the preoperatively available factors, clinical response (P=0.018), post-SUV_max-N (P=0.0001) and %SUV_max-T (P=0.0031) were significant prognostic factors by univariate analysis. The multivariate analysis identified post-SUV_max-N as the only significant prognostic predictor (P=0.0254). Patients with a post-SUV_max-N of <3.0 exhibited significantly fewer pathological metastatic nodes and better disease-free survival compared with patients with a post-SUV_max-N >3.0. Therefore, post-SUV_max-N may be a useful prognostic predictor in patients with advanced esophageal cancer who are treated with NAC followed by surgery.

Prognostic value of metabolic response measured by 18F-FDG-PET in oesophageal cancer patients treated with definitive chemoradiotherapy

BACKGROUND

This study aimed to assess the efficacy of fluorine-18 fluorodeoxyglucose (F-FDG)-PET for predicting overall survival (OS) and disease-free survival (DFS) in oesophageal cancer patients after definitive chemoradiotherapy (CRT) and prognostic importance of metabolic response detected by post-treatment PET at least 3 months after completing CRT.

MATERIALS AND METHODS

Data from 58 oesophageal cancer patients receiving definitive CRT were retrospectively analysed. Post-treatment F-FDG-PET was delivered at a median of 3.2 (range, 3.0-6.4) months after CRT. The impact of metabolic response determined by post-treatment F-FDG-PET, maximum post-treatment standardized uptake value (SUVmax) and percent SUV change (pretreatment to post-treatment) on survival was analysed.

RESULTS

The median follow-up was 19.7 (range, 4.2-91.9) months for all patients and 28.2 (range, 13.7-91.9) months for survivors. The mean pretreatment and post-treatment SUVmax and the median percent SUV decrease were 18.6±6.4, 6.2±4.6 and -73% (+13 to -100%). Pretreatment SUVmax was higher in patients with locoregional or distant failure than in those without (P<0.001). Pretreatment SUVmax was lower in patients with a complete response (CR) than in those without a CR (P=0.006). Two-year OS and DFS were higher in patients with CR compared with those without CR (P<0.001). CR rates detected by post-treatment F-FDG-PET were lower in patients with lymph node metastases or longer tumours than in those with shorter tumours or no metastases. During multivariate analysis, post-treatment SUVmax was a significant predictor for OS, and post-treatment SUVmax, percent SUV decrease and tumour length were significant prognostic factors for DFS.

CONCLUSION

Metabolic response assessed by post-treatment F-FDG-PET at least 3 months after CRT showed that post-treatment SUVmax and percent SUV change were important survival predictors.

Effectiveness of Repeat 18F-Fluorodeoxyglucose Positron Emission Tomography Computerized Tomography (PET-CT) Scan in Identifying Interval Metastases for Patients with Esophageal Cancer

INTRODUCTION

An 18F-fluorodeoxyglucose positron emission tomography-computerized tomography (PET-CT) scan is performed after neoadjuvant chemoradiation (nCRT) to restage esophageal cancer. The purpose of this study was to determine the ability of PET-CT to accurately identify interval metastatic disease following nCRT.

METHODS

This was a single-institution retrospective review (January 2005-February 2012) of patients with esophageal cancer treated with nCRT who underwent pre- and post-nCRT PET-CT.

RESULTS

A total of 283 patients were treated with nCRT, of whom 258 (91.2%) had both a pre- and post-nCRT PET-CT. On the post-nCRT PET-CT, 64 patients (24.8%) had interval findings concerning for metastatic disease. Of these patients, only 10 (15.6%) had true-positive findings of metastatic disease (six biopsy proven). The sites of interval metastases included bone (4), liver (3), peritoneum (1), mediastinal lymph nodes (1), and cervical lymph nodes (1). The positive predictive value of post-nCRT PET-CT for interval metastases was 15.6% (10/64), and the yield for detecting metastases since the pre-nCRT PET-CT was 3.9% (10/258). The work-up of the 54 patients (20.9% of the initial starting group) with false-positive post-nCRT findings included biopsy (24.6%) and immediate additional imaging (45.2%). A total of 208 patients proceeded with surgery: 163 (78.4%) had no new findings on post-nCRT PET-CT, and 45 (21.6%) had new false-positive findings. False-positive sites mainly included the lung (15) and liver (14).

CONCLUSIONS

The yield of post-nCRT PET-CT for the detection of new metastatic disease was 3.9%. Post-nCRT PET-CT often leads to a high proportion of false positives and subsequent investigational work-up.

Impact of PET/CT on radiation treatment in patients with esophageal cancer: A systematic review

PURPOSE

With the advances in radiotracers, positron emission tomography/computed tomography (PET/CT) is recognized as a useful adjunct to anatomic imaging with CT, MRI and endoscopic ultrasonography (EUS). The objective of this review was to comprehensively analyze the roles of PET/CT for the radiotherapy of esophageal cancer.

METHODS

In this review, we focused on issues concerning the application of PET/CT in TNM staging, target volume delineation and response to therapy, both for the primary tumor and regional lymph nodes. Furthermore, the following questions were addressed: how does PET/CT guide appropriate treatment protocols, how does it allow accurate tumor delineation and how does it guide prognosis and future treatment decisions.

RESULTS AND CONCLUSION

For the staging of esophageal cancer, PET/CT played a crucial role in exploring distant malignant lymph nodes and metastasis with high sensitivity, specificity and accuracy. PET/CT using different radiotracer provided a serial of thresholding methods based on standardized uptake value (SUV) to assist in auto-contouring the gross tumor volume (GTV). The change in SUV may offer a potential paradigm of personalized treatment to definitive chemoradiotherapy (CRT). In total, PET/CT has sought to further optimize radiotherapy treatment planning for patients with esophageal cancer.

The role of PET and PET-CT scanning in assessing response to neoadjuvant therapy in esophageal carcinoma

BACKGROUND

The response to neoadjuvant (radio-)chemotherapy for esophageal carcinoma is often assessed with the aid of positron-emission tomography (PET), either alone or in combination with computed tomography (PET-CT). In this review, we discuss the diagnostic validity and clinical benefit of these imaging techniques.

METHODS

We systematically searched the Medline, Embase, and Cochrane Library databases for randomized controlled trials (RCTs) and controlled clinical trials (CCTs) comparing PET-CT with conventional techniques such as endosonography and CT. We then determined the diagnostic validity of these methods on the basis of information from published systematic reviews, updated with further information from more recent primary studies.

RESULTS

We did not find any RCTs that addressed the question of the patient-relevant benefit of PET-CT. We found 20 studies of diagnostic methods, carried out on a total of 854 patients, of whom 82.2% were male. These studies had a high potential for bias. In two of them, PET-CT was directly compared with endosonography or CT. Estimates of sensitivity and specificity varied widely across studies. 54% of all patients (median value across studies) had no histopathological response to therapy at the end of treatment. Taking a reduction of the standard uptake value (SUV) by at least 35% as a threshold criterion, we found that the median negative predictive value of PET across all studies was 86.5.

CONCLUSION

There is no robust evidence for a patient-relevant benefit of PET and PET-CT in patients with esophageal carcinoma. PET could potentially be used to distinguish treatment responders from non-responders after the first cycle of treatment. RCTs with patient-relevant endpoints will be needed in order to determine whether this is useful.

State-of-the-art molecular imaging in esophageal cancer management: implications for diagnosis, prognosis, and treatment

Molecular imaging techniques are increasingly being used in addition to standard imaging methods such as endoscopic ultrasound (EUS) and computed tomography (CT) for many cancers including those of the esophagus. In this review, we will discuss the utility of the most widely used molecular imaging technique, (18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography (PET). (18)F-FDG PET has a variety of potential applications ranging from improving staging accuracy at the time of initial diagnosis to assisting in radiation target volume delineation. Furthermore, (18)F-FDG PET can be used to evaluate treatment response after completion of neoadjuvant therapy or potentially during neoadjuvant therapy. Finally, we will also discuss other novel molecular imaging techniques that have potential to further improve cancer care.

Prognostic Significance of (18)F-fluorodeoxyglucose Positron Emission Tomography (FDG-PET)-Positive Lymph Nodes Following Neoadjuvant Chemotherapy and Surgery for Resectable Thoracic Esophageal Squamous Cell Carcinoma

PURPOSE

Patients with resectable thoracic esophageal squamous cell cancer (TESCC) and positron emission tomography (PET)-positive lymph nodes (PET-N positive) are likely to have ≥3 pathological lymph node metastases (pLNMs) and show a higher rate of postoperative recurrence despite curative resection than PET-N-negative TESCC patients. We examined the prognostic significance of (18)F-fluorodeoxyglucose uptake into lymph node metastases after neoadjuvant chemotherapy (NAC) for PET-N positive TESCC and aimed to propose the optimal NAC response criteria for these patients.

METHODS

Fifty-one patients with PET-N positive TESCC underwent two courses of NAC followed by surgery. Metabolic responses of primary tumors and LNs were prospectively evaluated and associations with clinicopathological data and patient survival assessed by univariate and multivariate analyses.

RESULTS

After NAC, 21 patients were post-treatment (post-) PET-N positive and 30 post-PET-N negative. A significantly (p < 0.001) high proportion of the post-PET-N-negative group had ≤2 pLNMs than the post-PET-N positive group (86.7 vs. 28.6 %). The PET-N negative group also had a significantly lower distant metastasis rate (23.3 vs. 75.0 %) and higher 5-year relapse-free survival (RFS) rate (69.0 vs. 20.0 %). Univariate and multivariate Cox's proportional hazard regression analyses identified post-PET-N negative status as the only significant favorable predictive factor for low postoperative recurrence (p = 0.015) independent of the primary tumor response.

CONCLUSIONS

PET-N negative status predicts ≤2 pLNMs and longer RFS in resectable TESCC patients even after NAC. Therefore, post-PET-N status, not the effects on the primary tumor, is a critical NAC treatment response criterion for evaluating prognosis and guiding subsequent treatment.

Value of CT–PET after neoadjuvant chemoradiation in the prediction of histological tumour regression, nodal status and survival in oesophageal adenocarcinoma

Background

The role of CT–PET after neoadjuvant chemoradiation (nCRT) for prediction of pathological response and oncological outcome in oesophageal and junctional adenocarcinoma (OAC) is unclear. The relationship between complete metabolic response (cMR), pathological complete response (pCR) and nodal status has not been clarified.

Methods

Patients with locally advanced OAC selected to receive nCRT and surgery with curative intent, on the basis of staging that included CT–PET positivity, were included. Repeat scanning (PET2) with an identical protocol was performed 2–4 weeks after completion of nCRT (cisplatin and 5-fluorouracil plus 44 Gy radiation). Changes in [18F]fluorodeoxyglucose uptake, considered as either a maximum standardized uptake value (SUVmax) or a relative reduction (%ΔSUVmax), and PET-predicted nodal status following nCRT were compared with histopathological response, histological node positivity and survival.

Results

One hundred consecutive patients with PET-positive OAC were studied. Following nCRT, PET2 identified M1 disease in 2·0 per cent of patients. There were no significant associations between PET2 SUVmax or %ΔSUVmax with respect to primary tumour stage (ypT) (P = 0.216 and P = 0·975 respectively), tumour regression grade (P = 0·109 and P = 0·232), pCR (P = 0·633 and P = 0·870) or complete resection (R0) (P = 0·440 and P = 0·235). The sensitivity of PET2 for ypN was 10 per cent. %ΔSUVmax was not associated with disease-free or overall survival (P = 0·162 and P = 0·154 respectively). Of 46 patients with a cMR on PET2, 37 (80 per cent) had histological evidence of residual tumour in the resected specimen, and cMR was not associated with overall survival benefit (P = 0·478).

Conclusion

CT–PET following nCRT for OAC has poor prognostic and discriminatory value for clinical application.

A systematic review of the predictive value of (18)FDG-PET in esophageal and esophagogastric junction cancer after neoadjuvant chemoradiation on the survival outcome stratification

PURPOSE

We studied the predictive value of [(18) F]fluorodeoxyglucose-positron emission tomography ((18)FDG-PET) for assessing disease-free (DFS) and overall survival (OS) in esophageal and esophagogastric junction cancer.

MATERIALS AND METHODS

A literature search (PUBMED/MEDLINE, EMBASE, Cochrane) was performed to identify full papers with (18)FDG-PET and survival data, using indexing terms and free text words. Studies with >10 patients with locally advanced esophageal cancer, presenting sequential or at least one post-adjuvant treatment (18)FDG-PET data and Kaplan-Meier survival curves with >6 months median follow-up period were included. We performed a meta-analysis for DFS and OS using the hazard ratio (HRs) as outcome measure. Sources of heterogeneity study were also explored.

RESULTS

We identified 26 eligible studies including a total of 1,544 patients (average age 62 years, 82% males). The TNM distribution was as follows: stage I 7%, II 24%, III 53% and IV 15%. The pooled HRs for complete metabolic response versus no response were 0.51 for OS (95% CI, 0.4-0.64; P < 0.00001) and 0.47 for DFS (95% CI, 0.38-0.57; P < 0.00001), respectively. No statistical heterogeneity was present. To explore sources of clinical heterogeneity, we also realised subgroup and regression analyses. Taken into account the moderate correlation between OS and DFS (ρ = 0.54), we used joint bivariate random regression model. These analyses did not show a statistically significant impact of study characteristics and PET modalities on the pooled outcome estimates.

CONCLUSION

Despite methodological and clinical heterogeneity, metabolic response on (18)FDG-PET is a significant predictor of long-term survival data.

Role of surgical resection in complete responders on FDG-PET after chemoradiotherapy for locally advanced esophageal squamous cell carcinoma

BACKGROUND AND OBJECTIVES

To determine the role of surgery in complete responders on FDG-PET after CRT and the prognostic significance of metabolic response in locally advanced esophageal squamous cell carcinoma.

METHODS

We retrospectively reviewed 154 patients with locally advanced esophageal cancer with increased uptake on FDG-PET. Eighty-one patients received definitive CRT and 73 received trimodality therapy. We defined metabolic complete remission (PET-CR) when FDG uptake of the primary tumor and lymph nodes were decreased and was indistinguishable from surrounding normal tissue. Oncologic outcomes were compared between trimodality group, definitive CRT group, and PET-CR subgroup of definitive CRT.

RESULTS

Thirty-one (38.3%) of the definitive CRT patients and 39 (53.4%) of the trimodality therapy patients achieved PET-CR after CRT. The 2-year OS of the trimodality group was higher than that of the definitive CRT group, but equivalent to that of the PET-CR subgroup of definitive CRT. The 2-year LRFS and DFS of the trimodality group were higher than that of the PET-CR subgroup or the entire of definitive CRT group.

CONCLUSION

The addition of surgery showed higher DFS and LRFS rates than those of the PET-CR subgroup of definitive CRT. Despite achieving PET-CR, surgery still seems to improve local tumor control.

Postchemoradiotherapy positron emission tomography predicts pathologic response and survival in patients with esophageal cancer

PURPOSE

To correlate the prechemoradiotherapy (CRT) and post-CRT metabolic tumor volume (MTV) on positron emission tomography (PET) scanning with the pathologic response and survival in patients receiving preoperative CRT for esophageal cancer.

MATERIALS AND METHODS

The medical records of 37 patients with histologically confirmed Stage I-IVA esophageal cancer treated with CRT with or without surgical resection were reviewed. Of the 37 patients, 21 received preoperative CRT (57%) and 16 received definitive CRT (43%). All patients had a pre-CRT and 32 had a post-CRT PET scan. The MTV was measured on the pre-CRT PET and post-CRT PET scan, respectively, using a minimum standardized uptake value (SUV) threshold x, where x = 2, 2.5, 3, or the SUV maximum × 50%. The total glycolytic activity (TGA(x)) was defined as the mean SUV × MTV(x). The MTV ratio was defined as the pre-CRT PET MTV/post-CRT MTV. The SUV ratio was defined similarly. A single pathologist scored the pathologic response using a tumor regression grade (TRG) scale.

RESULTS

The median follow-up was 1.5 years (range, 0.4-4.9). No significant correlation was found between any parameters on the pre-CRT PET scan and the TRG or overall survival (OS). Multiple post-CRT MTV values and post-TGA values correlated with the TRG and OS; however, the MTV(2.5(Post)) and TGA(2.5(Post)) had the greatest correlation. The MTV(2) ratio correlated with OS. The maximum SUV on either the pre-CRT and post-CRT PET scans or the maximum SUV ratio did not correlate with the TRG or OS. Patients treated preoperatively had survival similar compared with those treated definitively with a good PET response (p = 0.97) and significantly better than that of patients treated definitively with a poor PET response (p < 0.0001).

CONCLUSION

The maximum SUV was not a predictive or prognostic parameter. The MTV(2.5) and TGA(2.5) were useful markers for predicting the response and survival on the post-CRT PET scan. The MTV(2) ratio also correlated with survival. Post-CRT PET can potentially guide therapy after CRT.

Can ¹⁸F-fluorodeoxyglucose positron emission tomography predict responses to neoadjuvant therapy in oesophageal cancer patients? A meta-analysis

OBJECTIVES

Neoadjuvant therapy for the treatment of oesophageal cancer was introduced in an effort to improve prognosis. Response assessment is crucial for the treatment of patients with oesophageal cancer. Currently, ¹⁸F-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET) seems to be the best available tool to assess neoadjuvant therapy response in patients with oesophageal cancer. The purpose of this study was to assess the diagnostic value of ¹⁸F-FDG PET for the evaluation of neoadjuvant therapy responses in patients with oesophageal cancer using a meta-analysis. A unified procedure and evaluation standard for ¹⁸F-FDG PET in the assessment of neoadjuvant therapy response should be established.

METHODS

All published English-language studies pertaining to the assessment of neoadjuvant therapy response in patients with oesophageal cancer using ¹⁸F-FDG PET in the MEDLINE and EMBASE databases were collected. The methodological quality of the included studies was evaluated according to the Quality Assessment of Diagnostic Accuracy Studies quality assessment tool. Pooled sensitivity, specificity, diagnostic odds ratios and summary receiver operating characteristic curves were obtained using statistical software.

RESULTS

Thirteen studies included in the meta-analysis fulfilled the inclusion criteria of the Quality Assessment of Diagnostic Accuracy Studies quality assessment tool. The pooled sensitivity, specificity and diagnostic odds ratios for F-¹⁸FDG PET in the evaluation of neoadjuvant therapy response in patients with oesophageal cancer were 70.3% [95% confidence interval (CI): 64.4-75.8], 70.1% (95% CI: 65.1-74.8) and 9.389 (95% CI: 3.482-25.319), respectively. The area under the curve and the Q value for the summary receiver operating characteristic curve were 0.8244 and 0.7575, respectively.

CONCLUSION

¹⁸F-FDG PET has some value in the assessment of neoadjuvant therapy response in patients with oesophageal cancer. A 50% reduction in standardized uptake value between pretherapy and posttherapy positron emission tomography scans performed in the first 2 weeks after the initiation of neoadjuvant therapy is the optimal condition for predicting a response to neoadjuvant therapy in patients with oesophageal cancer.

F-18 FDG PET/CT contributes to more accurate detection of lymph nodal metastasis from actively proliferating esophageal squamous cell carcinoma

PURPOSE

Evaluating the status of disease progression is critical for planning a therapeutic strategy for esophageal cancer. In this regard, F-18 fluorodeoxyglucose-labeled positron emission tomography (PET) is one of the most useful diagnostic modalities. However, there is room to improve its diagnostic performance, such as distinguishing lymph nodal metastases from false positives. In this study, we examined the diagnostic accuracy of fluorodeoxyglucose PET accompanied by computed tomography imaging (PET/CT) to detect regional lymph nodal metastasis from esophageal squamous cell carcinoma (ESCC).

METHODS

A total of 102 patients diagnosed as ESCC were subjected to this study. These patients had a preoperative PET/CT examination to evaluate the existence of metastasis. The values of maximum standardized uptake value (SUVmax) in primary tumors and in metastasized lymph nodes were measured to analyze their relationship with various clinicopathologic characteristics including the status of tumor cell proliferation, which was assessed by immunohistochemistry for Ki-67.

RESULTS

The SUVmax of the primary tumor was positively correlated with tumor size and vessel invasion, and was positively related with the SUVmax of lymph nodal metastasis, especially in cases of poorly differentiated ESCC. The SUVmax of metastasized lymph nodes was higher in larger-sized metastasized lymph nodes, whereas the Ki-labeling index of lymph nodal metastasis was positively related with the SUVmax per unit area (SUVmax/mm). The diagnostic accuracy of PET/CT (87.3%) was higher than that of conventional CT scans (78.4%).

CONCLUSIONS

The improved diagnostic accuracy of PET/CT can be explained by its ability to detect actively progressive metastasis at an early phase regardless of size.

Treatment of T4 esophageal cancer. Definitive chemo-radiotherapy vs chemo-radiotherapy followed by surgery

The outcome of patients with T4 esophageal cancer, defined as a tumor that invades neighboring structures (e.g., aorta, trachea, bronchus, and lung), is extremely poor. Despite recent advances in surgical techniques, these tumors are usually considered inoperable. Two distinct therapeutic options are currently available for T4 esophageal cancers: chemo-radiotherapy followed by surgery (CRT-S), which comprises esophagectomy following down-staging of the tumor by CRT, and definitive chemo-radiotherapy (D-CRT), which is designed to avoid esophagectomy by using maximum doses of irradiation. CRT-S is superior to D-CRT with respect to local control and short-term survival although CRT-S is associated with relatively higher perioperative mortality and morbidity. On the other hand, it is sometimes difficult to achieve local control with D-CRT and the treatment often results in fistula formation, though a complete response to CRT is often associated with better prognosis. Admittedly, the difference in the survival rate between the two modalities is marginal at long-term follow-up due to operative morbidity and inadequate control of distant metastasis in CRT-S. Changes in perioperative management and intensive systemic chemotherapy may enhance the outcome. Randomized controlled trials involving large population samples are needed to define the standard treatment for T4 esophageal cancer.

The impact of ¹⁸F-fluorodeoxyglucose positron emission tomography positive lymph nodes on postoperative recurrence and survival in resectable thoracic esophageal squamous cell carcinoma

BACKGROUND

Induction therapy is not always beneficial for all patients. Therefore, it is important to identify the patients with a high rate of recurrence. The occurrence of lymph node metastases (LNMs) strongly influences the postoperative survival in patients with esophageal cancer. We investigated the usefulness of an LN evaluation by initial (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in prediction of postoperative recurrence for patients with resectable esophageal squamous cell carcinoma (ESCC).

METHODS

A total of 76 ESCC patients who did not undergo induction therapy, but who did receive a curative resection were divided into PET-node (PET-N) positive (n = 26) and negative (n = 50) groups according to the presence or absence of FDG uptake in LNs. The PET-N status was compared with the size and the number of LNMs, as well as with the survival and failure patterns.

RESULTS

PET positive LNs involved a significantly larger size of metastatic nests than PET negative LNs (P = 0.002). The PET-N negative group showed a higher proportion of patients with 2 or fewer LNMs (92.0%), a higher 5-year relapse-free survival (75.1%) and a higher overall survival (70.0%), and a lower postoperative recurrence (24.0%) than the 15.4, 29.6, 30.3, and 69.2% values in the PET-N positive group, respectively, (P < 0.005). Multivariate analyses identified the PET-N status to be the most significant preoperative risk factor for postoperative recurrence (P = 0.031).

CONCLUSION

The preoperative PET-N status in patients with resectable ESCC was significantly associated with the size and the number of LNMs and was therefore found to reliably identify the high-risk population for postoperative recurrence.

FDG-PET parameters as prognostic factor in esophageal cancer patients: a review

BACKGROUND

(18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) has been used extensively to explore whether FDG Uptake can be used to provide prognostic information for esophageal cancer patients. The aim of the present review is to evaluate the literature available to date concerning the potential prognostic value of FDG uptake in esophageal cancer patients, in terms of absolute pretreatment values and of decrease in FDG uptake during or after neoadjuvant therapy.

METHODS

A computer-aided search of the English language literature concerning esophageal cancer and standardized uptake values was performed. This search focused on clinical studies evaluating the prognostic value of FDG uptake as an absolute value or the decrease in FDG uptake and using overall mortality and/or disease-related mortality as an end point.

RESULTS

In total, 31 studies met the predefined criteria. Two main groups were identified based on the tested prognostic parameter: (1) FDG uptake and (2) decrease in FDG uptake. Most studies showed that pretreatment FDG uptake and postneoadjuvant treatment FDG uptake, as absolute values, are predictors for survival in univariate analysis. Moreover, early decrease in FDG uptake during neoadjuvant therapy is predictive for response and survival in most studies described. However, late decrease in FDG uptake after completion of neoadjuvant therapy was predictive for pathological response and survival in only 2 of 6 studies.

CONCLUSIONS

Measuring decrease in FDG uptake early during neoadjuvant therapy is most appealing, moreover because the observed range of values expressed as relative decrease to discriminate responding from nonresponding patients is very small. At present inter-institutional comparison of results is difficult because several different normalization factors for FDG uptake are in use. Therefore, more research focusing on standardization of protocols and inter-institutional differences should be performed, before a PET-guided algorithm can be universally advocated.

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.

Positron emission tomography’s changing significance in the treatment of esophageal cancer

Incidence of esophageal cancer has been rising, and Positron Emission Tomography (PET) is one tool that has shown utility and promise as a tool for staging, treatment response, and prognosis. PET delivery has evolved over time and is now frequently registered with a CT scan at the time of acquisition. However, resolution and confounders such as post-treatment radiation changes may limit clinical utility. PET has been shown to be helpful in staging, especially in evaluating for distant metastases. PET acquired after chemoradiation may give important prognostic information that can guide additional treatment decisions. Studies have had substantial variability in recommendations for the timing and manner of using PET for this purpose, and additional study is needed.