18F-Fluorodeoxiglucose Positron Emission Tomography for the Evaluation of Neoadjuvant Therapy Response in Esophageal Cancer: Systematic Review of the Literature

Correlation between metabolic response determined with [18F]FDG PET/CT and pathological response after neoadjuvant treatment and surgery in patients with esophageal cancer

AIM

To assess the correlation between the result of the PET/CT study with [18F]FDG and the histological outcome in patients with esophageal cancer undergoing chemoradiotherapy and subsequent surgery.

MATERIAL AND METHODS

41 patients (35 men) diagnosed with esophageal cancer during a 10-year interval were retrospectively evaluated. PERCIST criteria and SULpeak (ΔSULpeak) variation between pre- and post-treatment PET/CT studies were used. After neoadjuvant treatment and subsequent surgery, histological response and patient survival were determined, correlating the findings with the result of the metabolic study. Different parameters related to patient and tumors lesion characteristics were compared with respect to histologic response. ROC curves and the Kaplan-Meier method were applied for the analysis of prognostic factors and survival curves.

RESULTS

The mean follow-up was 34.9 months, with 21 relapses-progressions and 25 deaths. Significant differences were demonstrated between histologic responses regarding PERCIST criteria and ΔSULpeak. Both showed adequate sensitivity and moderate specificity in relation to their histological correlation. No significant differences were found with respect to other parameters studied. Survival analysis showed significantly different progression-free survival curves for the ΔSULpeak and histologic outcome.

CONCLUSION

PERCIST criteria and ΔSULpeak differentiated between patients with and without histological response. ΔSULpeak and histological results proved to be prognostic factors. The results could help to personalize treatment and, together with other determinations, allow an active surveillance approach could be contemplated.

[18F]FDG-PET-Based Personalized Radiotherapy Dose Prescription

PET imaging with 2'-deoxy-2'-[18F]fluoro-D-glucose ([18F]FDG) has become one of the pillars in the management of malignant diseases. It has proven value in diagnostic workup, treatment policy, follow-up, and as prognosticator for outcome. [18F]FDG is widely available and standards have been developed for PET acquisition protocols and quantitative analyses. More recently, [18F]FDG-PET is also starting to be appreciated as a decision aid for treatment personalization. This review focuses on the potential of [18F]FDG-PET for individualized radiotherapy dose prescription. This includes dose painting, gradient dose prescription, and [18F]FDG-PET guided response-adapted dose prescription. The current status, progress, and future expectations of these developments for various tumor types are discussed.

Role of (F-18) Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in the Prediction of Response to Neoadjuvant Therapy in Esophageal Cancer: Correlation with Pathological Response and Survival

Purpose

The purpose of this study is to assess the correlation between metabolic response with fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) and pathological response in patients with locally advanced esophageal cancer treated with neoadjuvant chemoradiotherapy and to study FDG-PET parameters for the prediction of pathological response and outcome.

Methods

Twenty-five patients with locally advanced esophageal cancer underwent two FDG-PET/CT scans for initial staging and after neoadjuvant chemoradiotherapy. FDG uptake in the primary tumor was calculated in both scans (SUVmax, SULpeak, and TLG). Metabolic response was assessed according to the reduction of PET parameters: complete response (mCR = 100%), partial response (mPR ≥50%), and no response (mNR ≤50%). Pathological response was also classified as complete (pCR), partial (pPR), or no response (pNR). Patients were followed up (range, 8-99 months) determining free-disease interval (FDI) and overall survival (OS).

Results

Two patients were excluded due to exitus for nonesophageal-related causes. The metabolic response was observed in 18/23 remaining patients (3mCR, 15 mPR), of which 12/18 patients showed a pathological response (3 pCR, 9 pPR). A major discrepancy was observed in 2 mNR patients who achieved pPR. FDI and OS were longer in patients with metabolic response than nonresponders, but no statistical difference was found. No significant correlation was found between PET parameters and pathological response, FDI, and OS.

Conclusions

FDG-PET/CT is a useful technique to assess response to neoadjuvant chemoradiotherapy in esophageal cancer. Although in this preliminary study, no correlation between metabolic and pathologic response was found and no statistical differences between responders and nonresponders were observed, a tendency of longer FDI and OS was apparently found in responders patients.

Significance of mid-radiotherapy 18F-fluorodeoxyglucose positron emission tomography/computed tomography in esophageal cancer

BACKGROUND AND PURPOSE

Metabolic parameters evaluated by 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) are known as prognostic markers in various cancers. We aimed to validate the predictive value of mid-radiotherapy (RT) FDG PET/CT parameters in esophageal cancer.

MATERIALS AND METHODS

Eighty-three patients treated with RT with or without chemotherapy between 2015 and 2020 were included. PET parameters including metabolic tumor volume (MTV), total lesion glycolysis, and mean (SUV_mean) and maximum standardized uptake value (SUV_max) were analyzed. Locoregional recurrence-free rate (LRFR) and distant metastasis-free rate (DMFR) were analyzed.

RESULTS

The median follow-up period was 10.5 months. Mid-RT SUV_max was significantly associated with LRFR (HR 1.07, p = 0.009) and DMFR (HR 1.13, p=0.047) while mid-RT MTV was associated with DMFR (HR 1.06, p=0.007). Treatment response after RT was associated with overall survival (HR, 1.52, p=0.025). Further, treatment response was significantly associated with mid-RT SUV_max. The optimal cutoff value for mid-RT SUV_max in predicting LRFR and DMFR was 11 while cutoff value for mid-RT MTV was 15. The patients with mid-RT SUV_max≤11 showed superior LRFR and DMFR compared to SUV_max>11 (1-year LRFR; 73.4% vs 48.4%, p=0.028, 1-year DMFR; 74.6% vs 40.7%, p=0.007). The 1-year DMFR was significantly different between patients with mid-RT MTV≤15 and >15 (1-year DMFR; 78.2% vs 31.9%, p=0.002).

CONCLUSION

Tumor metabolism changes during RT can be a useful predictive tool for treatment response and recurrence in patients with esophageal cancer. Clinicians may consider early response evaluation with PET during RT for information about prognosis.

Prediction of the effects of radiation therapy in esophageal cancer using diffusion and perfusion MRI

Chemoradiation therapy (CRT) of locally advanced esophageal cancer (LAEC), although improving outcomes of patients, still results in 50% of local failure. An early prediction could identify patients at high risk of poor response for individualized adaptive treatment. We aimed to investigate physiological changes in LAEC using diffusion and perfusion magnetic resonance imaging (MRI) for early prediction of treatment response. In the study, 115 LAEC patients treated with CRT were enrolled (67 in the discovery cohort and 48 in the validation cohort). MRI scans were performed before radiotherapy (pre‐RT) and at week 3 during RT (mid‐RT). Gross tumor volume (GTV) of primary tumor was delineated on T2‐weighted images. Within the GTV, the hypercellularity volume (V_HC) and high blood volume (V_HBV) were defined based on the analysis of ADC and fractional plasma volume (Vp) histogram distributions within the tumors in the discovery cohort. The median GTVs were 28 cc ± 2.2 cc at pre‐RT and 16.7 cc ± 1.5 cc at mid‐RT. Respectively, V_HC and V_HBV decreased from 4.7 cc ± 0.7 cc and 5.7 cc ± 0.7 cc at pre‐RT to 2.8 cc ± 0.4 cc and 3.5 cc ± 0.5 cc at mid‐RT. Smaller V_HC at mid‐RT (area under the curve [AUC] = 0.67, P = .05; AUC = 0.66, P = .05) and further decrease in V_HC at mid‐RT (AUC = 0.7, P = .01; AUC = 0.69, P = .03) were associated with longer progression‐free survival (PFS) in both discovery and validation cohort. No significant predictive effects were shown in GTV and V_HBV at any time point. In conclusion, we demonstrated that V_HC represents aggressive subvolumes in LAEC. Further analysis will be carried out to confirm the correlations between the changes in image‐phenotype subvolumes and local failure to determine the radiation‐resistant tumor subvolumes, which may be useful for dose escalation.

Baseline 18F-FDG PET/CT quantitative parameters as prognostic factors in esophageal squamous cell cancer

AIM

To determine the utility of [¹⁸F]FDG PET/CT quantitative parameters as prognostic factors for the response to neoadjuvant treatment, progression-free survival (PFS) and cancer-specific survival (CSS) in patients with esophageal squamous cell carcinoma (SCC).

MATERIAL AND METHODS

Thirty patients (29 men) diagnosed with SCC were retrospectively evaluated over a 6-year interval. Metabolic parameters were determined: maximum SUV (SUVmax), mean SUV (SUVmed), metabolic tumor volume (MTV) and total lesion glycolysis (TLG) from baseline PET/CT study. After treatment with chemotherapy and/or radiotherapy, response to treatment and patient survival were assessed. The comparison of parameters between groups of responders and non-responders was carried out using a Mann-Whitney U test ROC curves and the Kaplan-Meier method were used for analysis of prognostic factors and survival curves.

RESULTS

The average follow-up was 22.4 months, with 22 recurrence-progressions and 25 deaths. Significant differences were demonstrated between responders and non-responders with respect to tumor size, MTV and TLG. Survival analysis found significant differences for SCE and CSS depending on these three parameters.

CONCLUSION

Metabolic parameters MTV and TLG, and tumor size were prognostic factors for neoadjuvant treatment response, PFS, and CSS in patients diagnosed with SCC. Neither SUVmax nor SUVmed were predictive for any of the evaluation criteria. Results could help to personalize patient treatment.

Baseline 18F-FDG PET/CT quantitative parameters as prognostic factors in esophageal squamous cell cancer

AIM

To determine the utility of 18F-FDG PET/CT quantitative parameters as prognostic factors for the response to neoadjuvant treatment, progression-free survival (PFS) and cancer-specific survival (CSS) in patients with esophageal squamous cell carcinoma (SCC).

MATERIAL AND METHODS

Thirty patients (29 men) diagnosed with SCC were retrospectively evaluated over a 6-year interval. Metabolic parameters were determined: maximum SUV (SUVmax), mean SUV (SUVmed), metabolic tumor volume (MTV) and total lesion glycolysis (TLG) from baseline PET/CT study. After treatment with chemotherapy and/or radiotherapy, response to treatment and patient survival were assessed. The comparison of parameters between groups of responders and non-responders was carried out using a Mann-Whitney U test. ROC curves and the Kaplan-Meier method were used for analysis of prognostic factors and survival curves.

RESULTS

The average follow-up was 22.4months, with 22 recurrence-progressions and 25 deads. Significant differences were demonstrated between responders and non-responders with respect to tumor size, MTV and TLG. Survival analysis found significant differences for SCE and CSS depending on these three parameters.

CONCLUSION

Metabolic parameters MTV and TLG, and tumor size were prognostic factors for neoadjuvant treatment response, PFS, and CSS in patients diagnosed with SCC. Neither SUVmax nor SUVmed were predictive for any of the evaluation criteria. Results could help to personalize patient treatment.

Prognostic values of mid-radiotherapy 18F-FDG PET/CT in patients with esophageal cancer

BACKGROUND

To identify whether early metabolic responses as determined using ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) during radiotherapy (RT) predict outcomes in patients with esophageal cancer.

METHODS

Twenty-one patients with esophageal cancer who received pre-treatment ¹⁸F-FDG PET/CT (PET1) and inter-fractional ¹⁸F-FDG PET/CT (PET2) after 11 fractions of RT (median 23.1 Gy, 2.1 Gy per fraction) were retrospectively reviewed. The region of interest for each calculation was delineated using "PET Edge". We calculated PET parameters including maximum and mean standardized uptake values (SUV_max and SUV_mean, respectively), metabolic tumor volume (MTV), and total lesion glycolysis (TLG). The relative changes (%) were calculated using the logarithmically transformed parameter values for the PET1 and PET2 scans. Multivariate analysis of locoregional recurrence and distant failures were performed using Cox regression analysis. After identifying statistically significant PET parameters for discriminating responders from non-responders, receiver operating characteristics curve analyses were used to assess the potentials of the studied PET parameters.

RESULTS

After a median follow-up of 13 months, the 1-year overall and progression-free survival rates were 79.0% and 34.4%, respectively. Four patients developed locoregional recurrences (LRRs) and 8 had distant metastases (DMs). The 1-year overall LRR-free rate was 76.9% while the DM-free rate was 60.6%. The relative changes in MTV (ΔMTV) were significantly associated with LRR (p = 0.03). Conversely, the relative changes in SUV_mean (ΔSUV_mean) were associated with the risk of DM (p = 0.02). An ΔMTV threshold of 1.14 yielded a sensitivity of 60%, specificity of 94%, and an accuracy of 86% for predicting an LRR. Additionally, a ΔSUV_mean threshold of a 35% decrease yielded a sensitivity of 67%, specificity of 83%, and accuracy of 76% for the prediction DM.

TRIAL REGISTRATION

Retrospectively registered.

CONCLUSIONS

Changes in tumor metabolism during RT could be used to predict treatment responses, recurrences, and prognoses in patients with esophageal cancer.

Role of 18F-fluorodeoxyglucose positron emission tomography/computed tomography in predicting pathological response to preoperative super-selective intra-arterial chemoradiotherapy for advanced squamous cell carcinoma of the mandible

Introduction

Although chemoradiotherapy (CRT) for oral squamous cell carcinoma (SCC) has been shown to preserve organ function and improve cosmetic results, site-specific data, especially mandible, are limited. The aim of this study was to evaluate the predictability of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) on response to super-selective intra-arterial CRT for advanced SCC of the mandible.

Methods

Fifteen patients with advanced SCC of the mandible underwent super-selective intra-arterial CRT followed by radical resection. Maximum standardized uptake value (SUVmax) of the mandibular lesion was evaluated with FDG-PET/CT before and after CRT. The SUVmax before and after CRT was defined as pre-SUVmax and post-SUVmax, respectively. The difference between pre- and post-SUVmax was calculated as SUVmax reduction rate to evaluate treatment response of the mandibular lesion. Each SUVmax reduction rate and surgical specimen of the corresponding lesion was analyzed to evaluate an accuracy of the modality for predicting pathological response.

Results

The median of pre-SUVmax was significantly lower than that of post-SUVmax (p = 0.001). Of the 15 patients, 6 had a pathological complete response (pCR) and 9 had a non-pCR. Neither pCR patients nor non-pCR patients showed significant difference of the median of SUVmax between pre- and post-CRT (pre-CRT p = 0.099 post-CRT p =0.074). The SUVmax reduction rate in patients with pCR was significantly higher than that with non-pCR (p = 0.002). Receiver operating characteristic analysis revealed that the optimal cut-off point of the reduction rate was 64.7%, with 83% sensitivity and 100% specificity.

Conclusions

These results concluded that SUVmax reduction rate can predict pathological complete response of preoperative super-selective intra-arterial CRT for advanced SCC of the mandible.

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.

Increased FDG uptake on late-treatment PET in non-tumour-affected oesophagus is prognostic for pathological complete response and disease recurrence in patients undergoing neoadjuvant radiochemotherapy

PURPOSE

Early side effects including oesophagitis are potential prognostic factors in patients undergoing radiochemotherapy (RCT) for locally advanced oesophageal cancer (LAEC). We assessed the prognostic value of ¹⁸F-fluorodeoxyglucose (FDG) uptake within irradiated non-tumour-affected oesophagus (NTO) during restaging positron emission tomography (PET) as a surrogate for inflammation/oesophagitis.

METHODS

This retrospective evaluation included 64 patients with LAEC who had completed neoadjuvant RCT and had successful oncological resection. All patients underwent FDG PET/CT before and after RCT. In the restaging PET scan maximum and mean standardized uptake values (SUV_max, SUV_mean) were determined in the tumour and NTO. Univariate Cox regression with respect to overall survival, local control, distant metastases and treatment failure was performed. Independence of clinically relevant parameters was tested in a multivariate Cox regression analysis.

RESULTS

Increased FDG uptake, measured in terms of SUV_mean in NTO during restaging was significantly associated with complete pathological remission (p = 0.002) and did not show a high correlation with FDG response of the tumour (rho < 0.3). In the univariate analysis, increased SUV_max and SUV_mean in NTO was associated with improved overall survival (p = 0.011, p = 0.004), better local control (p = 0.051, p = 0.044), a lower rate of treatment failure (p < 0.001 for both) and development of distant metastases (p = 0.012, p = 0.001). In the multivariate analysis, SUV_max and SUV_mean in NTO remained a significant prognostic factor for treatment failure (p < 0.001, p = 0.004) and distant metastases (p = 0.040, p = 0.011).

CONCLUSIONS

FDG uptake in irradiated normal tissues measured on restaging PET has significant prognostic value in patients undergoing neoadjuvant RCT for LAEC. This effect may potentially be of use in treatment personalization.

New approaches in esophageal carcinomas

New approaches in the treatment of esophageal cancer comprise endoscopy with refinements of esophagoscopic intraluminal resection by endoscopic submucosal dissection. Radical open surgery is more and more replaced by minimally invasive esophagectomy (MIO), especially in the hybrid technique with laparoscopic gastrolysis and transthoracic esophageal resection and gastric pull-up. Total MIO also in the robotic technique has not yet shown that it produces superior results than the hybrid technique. Fluorescent dye can improve the intraoperative visualization of the vascularization of the gastric conduit. The individualization of neoadjuvant therapy is the magic word in clinical research of multimodal treatment of esophageal cancer. This means response prediction based on molecular markers or clinical response evaluation. The documentation of the diversity of postoperative complications is now standardized by an international consensus. The value of enhanced recovery after surgery is not yet approved compared to conventional management.

Utility of 18F-FDG PET for Predicting Histopathologic Response in Esophageal Carcinoma following Chemoradiation

INTRODUCTION

For patients with esophageal cancer undergoing neoadjuvant chemoradiation (CRT) followed by surgical resection, complete histopathologic response (pCR) is associated with favorable overall survival (OS). The aim of this study was to evaluate the correlation between ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG PET) response to neoadjuvant CRT and pCR.

METHODS

Maximum standardized uptake values and standardized uptake ratios (SURs) were measured before and after CRT. SUR was normalized to liver uptake and mediastinal blood pool uptake. FDG PET complete response was defined as metabolic activity normalization to hepatic and blood pool activity. The correlation between FDG PET parameters and pCR was examined through logistic regression analyses.

RESULTS

In total, 193 patients were monitored for a median of 3.6 years after initiation of CRT. Most tumors were adenocarcinoma (85%) and stage T3 (75%). Complete FDG PET response and pCR occurred in 27% and 34% of patients, respectively. Histologic findings, chemotherapy type, tumor stage, and radiation dose were not significantly associated with complete radiographic response. The rates of pCR in patients with and without radiographic complete response were 42% and 31% (p = 0.17), respectively. No predictive correlation was found between pCR and change in maximum standardized uptake value (p = 0.25), in SUR normalized to blood pool uptake (p = 0.20), or in SUR normalized to liver uptake (p = 0.15). The 5-year OS rate was 46% for patients with a complete FDG PET response versus 44% without a complete response (p = 0.78). The 5-year OS rate of patients who achieved pCR was 49% versus 43% for patients with residual tumor (p = 0.04).

CONCLUSION

For patients with esophageal cancer who received neoadjuvant chemoradiation, pretreatment and posttreatment FDG PET parameters did not correlate with pCR or OS.

Circulating Tumor Cells in the Adenocarcinoma of the Esophagus

Circulating tumor cells (CTCs) are elements of indisputable significance as they seem to be responsible for the onset of metastasis. Despite this, research into CTCs and their clinical application have been hindered by their rarity and heterogeneity at the molecular and cellular level, and also by a lack of technical standardization. Esophageal adenocarcinoma (EAC) is a highly aggressive cancer that is often diagnosed at an advanced stage. Its incidence has increased so much in recent years that new diagnostic, prognostic and predictive biomarkers are urgently needed. Preliminary findings suggest that CTCs could represent an effective, non-invasive, real-time assessable biomarker in all stages of EAC. This review provides an overview of EAC and CTC characteristics and reports the main research results obtained on CTCs in this setting. The need to carry out further basic and translational research in this area to confirm the clinical usefulness of CTCs and to provide oncologists with a tool to improve therapeutic strategies for EAC patients was herein highlighted.

Esophageal cancer: anatomic particularities, staging, and imaging techniques

Cancer of the esophagus is a tumor with aggressive behavior that is usually diagnosed in advanced stages. The absence of serosa allows it to spread quickly to neighboring mediastinal structures, and an extensive lymphatic drainage network facilitates tumor spread even in early stages. The current TNM classification, harmonized with the classification for gastric cancer, provides new definitions for the anatomic classification, adds non-anatomic characteristics of the tumor, and includes tumors of the gastroesophageal junction. Combining endoscopic ultrasound, computed tomography, positron emission tomography, and magnetic resonance imaging provides greater accuracy in determining the initial clinical stage, and these imaging techniques play an essential role in the selection, planning, and evaluation of treatment. In this article, we review some particularities that explain the behavior of this tumor and we describe the current TNM staging system; furthermore, we discuss the different imaging tests available for its evaluation and include a diagnostic algorithm.

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.

Neoadjuvant treatment for advanced esophageal cancer: response assessment before surgery and how to predict response to chemoradiation before starting treatment

Patients with advanced esophageal cancer (T3-4, N) have a poor prognosis. Chemoradiation or chemotherapy before esophagectomy with adequate lymphadenectomy is the standard treatment for patients with resectable advanced esophageal carcinoma. However, only patients with major histopathologic response (regression to less than 10% of the primary tumor) after preoperative treatment will have a prognostic benefit of preoperative chemoradiation. Using current therapy regimens about 40% to 50% of the patients show major histopathological response. The remaining cohort does not benefit from this neoadjuvant approach but might benefit from earlier surgical resection. Therefore, it is an aim to develop tools for response prediction before starting the treatment and for early response assessment identifying responders. The current review discusses the different imaging techniques and the most recent studies about molecular markers for early response prediction. The results show that [(18)F]-fluorodeoxyglucose-positron emission tomography (FDG-PET) has a good sensitivity but the specificity is not robust enough for routine clinical use. Newer positron emission tomography detector technology, the combination of FDG-PET with computed tomography, additional evaluation criteria and standardization of evaluation may improve the predictive value. There exist a great number of retrospective studies using molecular markers for prediction of response. Until now the clinical use is missing. But the results of first prospective studies are promising. A future perspective may be the combination of imaging technics and special molecular markers for individualized therapy. Another aspect is the response assessment after finishing neoadjuvant treatment protocol. The different clinical methods are discussed. The results show that until now no non-invasive method is valid enough to assess complete histopathological response.

Radiation-Induced Esophagitis Masquerading as Disease Progression in Case of Esophageal Carcinoma: A Diagnostic Dilemma Solved on Follow-up FDG PET/CT

Radiation esophagitis is one of the commonest complications of the radiotherapy involving esophagus. It is characterized by diffuse radiotracer uptake in the esophagus on ¹⁸F-FDG PET/CT. Thus, it can be often confused with the esophageal malignancy. We present the sequential ¹⁸F-FDG PET/CT images of a 45-year-old woman with locally advanced squamous cell carcinoma of the esophagus who developed radiation esophagitis after chemoradiotherapy. It was confused with the progression of the disease, and the dilemma was resolved by the follow-up PET/CT.

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.

Degree of tumor shrinkage following neoadjuvant chemoradiotherapy: a potential predictor for complete pathological response in esophageal cancer?

Neoadjuvant chemoradiotherapy (CRT) before surgery results in a pathological complete response (pCR) rate in about 1/3 of the patients, which is correlated with survival. It was hypothesized that volumetric tumor response to CRT would correlate with outcomes. Patients who completed trimodality therapy, where planning, pre-, and post-CRT computed tomography scans were available, and pathology was reviewed by a central pathologist, were eligible for analysis. Absolute and relative tumor volume change pretreatment and post-treatment were correlated with pCR, locoregional recurrence (LRR), disease-free survival, and overall survival. Fifty-six patients were analyzed. pCR was observed in 30% of patients. Median follow up was 20.3 (range 4-89) months. The 2- and 4-year overall survival was 61.3% (95% confidence interval [CI]: 45-74) and 25.0% (95%CI: 11-41); proportion disease free was 32.1% (95% CI: 19-46) and 20.6% (9-36) at 2 and 4 years, respectively. The median relative volume reduction was 17% (95% CI: -24, -3%). Using 20% as the criteria, the proportion of patients with pCR of ≥20% versus <20% was 13/25 (52%) versus 4/31 (13%) for those who did not (odds ratio 7.3; 95% CI: 2-27). The LRR at 2 and 4 years were 29.5% (95% CI: 16-43) and 36.2% (95% CI: 23-50). The relative tumor reduction ≥20% was significantly correlated with LRR (hazard ratio 0.24; 95% CI: 0.07-0.8; p 0.02) at 2 and 4 years, respectively. Relative tumor volume reduction following CRT is correlated with pCR and LRR. Further investigations are warranted to examine the effect of volume change, alone or in conjunction with other factors as potential predictors for pathological response.

Current management of esophageal cancer

Management of esophageal cancer has evolved since the two last decades. Esophagectomy remains the primary treatment for early stage esophageal cancer although its specific role in superficial cancers is still under debate since the development of endoscopic mucosal treatment. To date, there is strong evidence to consider that locally advanced cancers should be recommended for a multimodal treatment with a neoadjuvant chemotherapy or a combined chemoradiotherapy (CRT) followed by surgery. For locally advanced squamous cell carcinoma or for a part of adenocarcinoma, some centers have proposed treating with definitive CRT to avoid related-mortality of surgery. In case of persistent or recurrent disease, a salvage esophagectomy remains a possible option but this procedure is associated with higher levels of perioperative morbidity and mortality. Despite the debate over what constitutes the best surgical approach (transthoracic versus transhiatal), the current question is if a minimally procedure could reduce the periopertive morbidity and mortality without jeopardizing the oncological results of surgery. Since the last decade, minimally invasive esophagectomy (MIE) or hybrid operations are being done in up to 30% of procedures internationally. There are some consistent data that MIE could decrease the incidence of the respiratory complications and decrease the length of hospital-stay. Nowadays, oncologic outcomes appear equivalent between open and minimally invasive procedures but numerous phase III trials are ongoing.

New directions in perioperative management of locally advanced esophagogastric cancer

Cancers of the esophagus arise as adenocarcinomas and squamous cell carcinomas; these represent distinct diseases, with differing prognosis, yet they are often studied in common trials. With surgery alone, 5 year survival for T2-T3N0 disease is less than 30% to 40%, and declines to less than 25% with nodal involvement. The CROSS randomly assigned patients to surgery alone or to weekly carboplatin/paclitaxel X 5 and 41.4 Gy concurrent radiotherapy, followed by surgery. Seventy-five percent of enrolled patients had adenocarcinoma. Preoperative combined-modality therapy improved R0 resection from 69% to 92% (p &lt; 0.001 and improved median survival from 24 months to 49.4 months (p &lt; 0.003). This regimen reduced both locoregional recurrence (34% to 14%; p &lt; 0.001) and the development of peritoneal carcinomatosis (14% to 4%; p &lt; 0.001). Systemic perioperative therapy may have a greater effect on distant disease, the predominant mode of failure for these patients, and current trials compare preoperative chemoradiation with periooperative systemic therapy. PET scan response during preoperative chemotherapy without radiotherapy correlates with improvements in pathologic response and with improved survival. Nonresponse on early PET scan allows identifıcation of patients for earlier surgery and discontinuation of ineffective preoperative chemotherapy, without survival detriment. There is no predictive benefıt for early PET scan during the course of chemotherapy followed by chemoradiotherapy. The use of early PET scan during induction chemotherapy is being evaluated in CALGB/Alliance trial (NCT01333033). Molecular profıling has identifıed somatic gene mutations and pathways that may be oncogenic in upper gastrointestinal cancers. Potential targets include the epidermal growth factor receptor (EGFR), vascular endothelial growth factor receptor (VEGFR), HER2, mammalian target of rapamycin (mTOR), fıbroblast growth factor receptor (FGFR), MEK, and others. Targeted therapies with known survival benefit in esophagogastric cancer are currently limited to trastuzumab for HER2 overexpressing cancers, or ramicirumab.

Determinants of response to neoadjuvant chemotherapy for esophageal cancer using 18F-fluorodeoxiglucose positron emission tomography (18F-FDG-PET)

BACKGROUND

(18)F-FDG-PET is potentially useful for evaluating response to neoadjuvant therapy for esophageal cancer. However, the optimal (18)F-FDG-PET parameter for evaluating the response to therapy and survival has not been established. This study aimed to select the best of the two parameters of fluorodeoxyglucose ((18)F-FDG)-positron emission tomography (PET): decreased ratio of maximal standardized uptake (SUVmax-DR) or absolute value of posttreatment SUVmax (post-SUVmax), in predicting response and survival of patients with esophageal cancer who underwent neoadjuvant chemotherapy.

METHODS

The study subjects were 211 consecutive patients with esophageal cancer who received neoadjuvant chemotherapy followed by surgery. (18)F-FDG-PET was performed before and 2-3 weeks after completion of neoadjuvant chemotherapy in assessment with pretreatment SUVmax (pre-SUVmax), post-SUVmax and SUVmax-DR.

RESULTS

The mean SUVmax decreased during neoadjuvant chemotherapy from 11.4 to 5.8, and the mean SUVmax-DR was 49.4%. Both post-SUVmax and SUVmax-DR correlated significantly with pathological response, although neither post-SUVmax nor SUVmax-DR could distinguish pathological complete response from pathological good response. The 5-year survival rate was significantly higher in patients with SUVmax-DR of >50% than those with <50% (56.5 vs. 39.6 %, p = 0.0137), and also significantly higher in patients with post-SUVmax of <3.5 than those with >3.5 (62.2 vs. 35.1%, p < 0.0001). Multivariate analysis identified post-SUVmax value, but not SUVmax-DR, as an independent prognostic factor in patients who underwent neoadjuvant chemotherapy.

CONCLUSIONS

Post-SUVmax is more useful for predicting survival of patients with esophageal cancer who undergo neoadjuvant therapy followed by surgery, although both SUVmax-DR and post-SUVmax equally correlate with pathological response.

Imaging-guided biopsy of (18)F-FDG-avid extrapulmonary lesions: do lesion location and morphologic features on CT affect the positive predictive value for malignancy?

OBJECTIVE

The purpose of our study was to analyze the effect of lesion location and morphologic appearance on CT on the positive predictive value (PPV) for malignancy of all extrapulmonary lesions that were (18)F-FDG avid on PET/CT and that were biopsied under imaging guidance.

MATERIALS AND METHODS

Between January 2004 and December 2010, 227 patients underwent imaging-guided biopsy of 231 PET-positive extrapulmonary lesions with diagnostic pathologic results. The PET PPV for malignancy was retrospectively calculated and stratified according to lesion location and morphologic appearance.

RESULTS

The overall PET PPV for malignancy was 72%. Inflammatory processes accounted for the majority of benign biopsy results. Lesion location significantly affected the PPV (p < 0.001). Bone (96%) and liver (90%) lesions had significantly higher PPVs for malignancy compared with other locations, whereas lymph nodes (60%) had a significantly lower PPV for malignancy. Lesions that were morphologically suspicious and morphologically benign according to CT findings alone were associated with PPVs of 74% and 57%, respectively (p = 0.05). FDG-avid subcentimeter lymph nodes (n = 8) had a PPV for malignancy of 38%.

CONCLUSION

Over half of PET-avid morphologically benign-appearing lesions and one third of PET-avid subcentimeter lymph nodes were found to be malignant at biopsy, suggesting that benign morphologic appearance alone should not preclude further workup of a PET-positive lesion. Biopsies of FDG-avid lesions in liver and bone yielded high rates of true malignancy, whereas biopsies of lymph nodes yielded a lower rate of malignancy compared with other lesion locations.

Relevance of [18F]fluorodeoxyglucose positron emission tomography-positive lymph nodes after neoadjuvant chemotherapy for squamous cell oesophageal cancer

Background

Several studies have examined the clinical significance of metabolic response in primary tumours by [18F]fluorodeoxyglucose positron emission tomography (18F-FDG-PET) in patients with oesophageal cancer who undergo neoadjuvant therapy. The relevance of the metabolic response in lymph nodes is unclear.

Methods

Consecutive patients with oesophageal cancer who underwent neoadjuvant chemotherapy followed by surgery were studied. 18F-FDG-PET was performed before and 2–3 weeks after completion of neoadjuvant chemotherapy, assessing FDG uptake in primary tumours and lymph nodes considered to be metastatic.

Results

Before therapy, 156 (73·9 per cent) of 211 patients had PET-positive nodes, of whom 89 (57.1 per cent) had no evidence of metabolic activity in these lymph nodes following chemotherapy. There was a significant relationship between post-treatment lymph node status assessed by FDG-PET and numbers of pathologically confirmed metastatic lymph nodes. Patients with post-treatment PET-positive nodes had shorter survival than those without (5-year survival rate 25 versus 62·6 per cent; P &lt; 0·001). There was no difference in survival between patients with PET-positive nodes before but not after therapy and patients who had PET-negative nodes throughout (5-year survival rate 59 versus 71 per cent respectively; P = 0·207). Multivariable analysis identified post-treatment nodal status assessed by FDG-PET and tumour depth as independent prognostic factors.

Conclusion

Identification of PET-positive lymph nodes after completion of chemotherapy is a predictor of poor prognosis of patients with oesophageal cancer scheduled for surgery. FDG-PET lymph node status after neoadjuvant chemotherapy is more important than that before chemotherapy.

Accuracy of multidetector-row CT for restaging after neoadjuvant treatment in patients with oesophageal cancer

OBJECTIVES

To assess the diagnostic accuracy of 64-multidetector CT (MDCT) for restaging of patients with oesophageal cancer undergoing neoadjuvant therapy.

METHODS

Results of pathological staging were correlated with those from 64-MDCT before and after neoadjuvant treatment in 35 patients using the American Joint Committee on Cancer/TNM classification (7th edition). CT response was determined using the Response Evaluation Criteria in Solid Tumours (RECIST) method, modified for one-dimensional tumour diameter measurement.

RESULTS

64-MDCT predicted T stage correctly in 34 % (12/35), overstaged in 49 % (17/35) and understaged in 17 % (6/35). Sensitivity/specificity values were as follows: T0, 20 %/92 %; T1-T2, 31 %/59 %; T3, 60 %/64 %; T4, 100 %/4 %. Negative predictive values for T3/T4 were 80 %/100 %. MDCT accurately predicted complete histopathological response in 20 % (accuracy 74 %) and overstaged in 80 %. Tumour regression grade was predicted correctly in only 8 % (2/25) and underestimated in 68 % (17/25). Accurate N stage was noted in 69 % (24/35).

CONCLUSION

Although MDCT tends to be able to exclude advanced tumour stages (T3, T4) with a higher likelihood, the diagnostic accuracy of high resolution MDCT for restaging oesophageal cancer and assessing the response to neoadjuvant therapy has not improved in comparison to older-generation CT. Therefore, the future assessment of oesophageal tumour response should focus on combined morphologic and metabolic imaging.

KEY POINTS

• Multidetector CT (MDCT) has been beneficial for the evaluation of many tumours. • However diagnostic accuracy for restaging oesophageal cancer has not improved with MDCT. • MDCT tends to be able to exclude advanced tumour stages (T3/T4). • MDCT has a low accuracy for determining lymph node metastasis. • Oesophageal tumour response should be assessed by combined morphological and metabolic imaging.

Management of advanced-stage operable esophageal cancer

The incidence of esophageal cancer is increasing in the developed world, with a relative increase in adenocarcinoma compared with squamous cell carcinoma. The distensible nature of the esophagus results in delayed development of symptoms associated with esophageal cancer; hence many patients have locally advanced or metastatic cancer at the time of initial presentation. Although resection remains the treatment of choice for early-stage esophageal cancer, the best treatment strategy for locally advanced esophageal cancer is debatable and, consequently, varies at different centers. This article discusses the published literature on various available therapeutic options for the treatment of locally advanced esophageal cancer.

Diagnosis and staging of cancer of the esophagus and esophagogastric junction

Esophageal/esophagogastric junction cancer staging in the 7th edition of the AJCC staging manual is data driven and harmonized with gastric staging. New definitions are Tis, T4, regional lymph node, N, and M. Nonanatomic characteristics (histopathologic cell type, histologic grade, cancer location) and TNM classifications determine stage groupings. Classifications before treatment define clinical stage (cTNM or ycTNM). Current best clinical staging modalities include endoscopic ultrasonography for T and N and CT/PET for M. Classifications at resection define pathologic stage (pTNM or ypTNM). Accurate pathologic stage requires communication/cooperation between surgeon and pathologist. Classifications are defined at retreatment (rTNM) and autopsy (aTNM).

Evaluation of response to neoadjuvant chemotherapy for esophageal cancer: PET response criteria in solid tumors versus response evaluation criteria in solid tumors

Recently, PET response criteria in solid tumors (PERCIST) have been proposed as a new standardized method to assess chemotherapeutic response metabolically and quantitatively. The aim of this study was to evaluate therapeutic response to neoadjuvant chemotherapy for locally advanced esophageal cancer, comparing PERCIST with the currently widely used response evaluation criteria in solid tumors (RECIST).

METHODS

Fifty-one patients with locally advanced esophageal cancer who received neoadjuvant chemotherapy (5-fluorouracil, adriamycin, and cisplatin), followed by surgery were studied. Chemotherapeutic lesion responses were evaluated using (18)F-FDG PET and CT according to the RECIST and PERCIST methods. The PET/CT scans were obtained before chemotherapy and about 2 wk after completion of chemotherapy. Associations were statistically analyzed between survival (overall and disease-free survival) and clinicopathologic results (histology [well-, moderately, and poorly differentiated squamous cell carcinoma], lymphatic invasion, venous invasion, clinical stage, pathologic stage, resection level, reduction rate of tumor diameter, reduction rate of tumor uptake, chemotherapeutic responses in RECIST and PERCIST, and pathologic response).

RESULTS

There was a significant difference in response classification between RECIST and PERCIST (Wilcoxon signed-rank test, P < 0.0001). Univariate analysis showed that lymphatic invasion, venous invasion, resection level, pathologic stage, and PERCIST were significant factors associated with disease-free or overall survival in this study. Although multivariate analysis demonstrated that venous invasion (disease-free survival: hazard ratio [HR] = 4.519, P = 0.002; overall survival: HR = 5.591, P = 0.003) and resection level (disease-free survival: HR = 11.078, P = 0.001) were the significant predictors, PERCIST was also significant in noninvasive therapy response assessment before surgery (disease-free survival: HR = 4.060, P = 0.025; overall survival: HR = 8.953, P = 0.034).

CONCLUSION

RECIST based on the anatomic size reduction rate did not demonstrate the correlation between therapeutic responses and prognosis in patients with esophageal cancer receiving neoadjuvant chemotherapy. However, PERCIST was found to be the strongest independent predictor of outcomes. Given the significance of noninvasive radiologic imaging in formulating clinical treatment strategies, PERCIST might be considered more suitable for evaluation of chemotherapeutic response to esophageal cancer than RECIST.

Comparative study between endoscopic ultrasonography and positron emission tomography-computed tomography in staging patients with esophageal squamous cell carcinoma

Treatment strategy of esophageal cancer mainly depends on accurate staging. At present, no single ideal staging modality is superior to another in preoperative tumor-node-metastasis (TNM) staging of patients with esophageal cancer. We aimed to investigate the efficacy of endoscopic ultrasonography (EUS) and positron emission tomography-computed tomography (PET-CT) for staging of esophageal cancer. We retrospectively studied 118 consecutive patients with esophageal squamous cell carcinoma who underwent esophagectomy with or without neoadjuvant chemoradiotherapy (CRT) over a near 3-year period between January 2005 and November 2008 at a tertiary hospital in Taiwan. Patients were separated into two groups: without neoadjuvant CRT (group 1, n= 28) and with CRT (group 2, n= 90). Medical records of demographic data and reports of EUS and PET-CT of patients before surgery were reviewed. A database of clinical staging by EUS and PET-CT was compared with one of pathological staging. The accuracies of T staging by EUS in groups 1 and 2 were 85.2% and 34.9%. The accuracies of N staging by EUS in groups 1 and 2 were 55.6% and 39.8%. The accuracies of T and N staging by means of PET-CT scan were 100% and 54.5% in group 1, and were 69.4% and 86.1% in group 2, respectively. In group 2, 38 of 90 patients (42.2%) achieved pathologic complete remission. Among them, two of 34 (5.9%) and 12 of 17 (70.6%) patients were identified as tumor-free by post-CRT EUS and PET-CT, respectively. EUS is useful for initial staging of esophageal cancer. PET-CT is a more reliable modality for monitoring treatment response and restaging. Furthermore, the accuracy of PET-CT with regard to N staging is higher in patients who have undergone CRT than those who have not.

Is the predictive ability of positron emission tomography after neoadjuvant treatment for esophageal cancer ready for prime-time?

Monjazeb et al performed a single-institution, retrospective study of 163 patients with histologically confirmed stage I to IVa esophageal cancer to assess the utility of positron-emission tomography (PET) in delineating which patients would most likely benefit from esophagectomy after induction chemoradiation therapy. They found that patients who achieve a PET complete response after definitive chemoradiation therapy had similar outcomes to patients treated with trimodal therapy and concluded that patients who achieve a PET complete response after induction therapy may not benefit from esophagectomy. Though their study is interesting, their results should be validated by a prospective trial before they are incorporated into clinical practice.

Pathologic nonresponders after neoadjuvant chemoradiation for esophageal cancer demonstrate no survival benefit compared with patients treated with primary esophagectomy

BACKGROUND

Neoadjuvant chemoradiation (NCRT) has become the preferred treatment for patients with locally advanced esophageal cancer. Survival often is correlated to degree of pathologic response; however, outcomes in patients who are found to be pathologic nonresponders (pNR) remain uninvestigated. This study was designed to evaluate survival in pNR to NCRT compared with patients treated with primary esophagectomy (PE).

METHODS

Using our comprehensive esophageal cancer database, we identified patients treated with NCRT and deemed pNR along with patients who proceeded to PE. Clinical and pathologic data were compared using Fisher's exact and χ(2), whereas Kaplan-Meier estimates were used for survival analysis.

RESULTS

We identified 63 patients treated with NCRT and were found to have a pNR, and 81 patients who underwent PE. Disease-free (DFS) and overall survival (OS) were significantly decreased in the pNR group compared with those treated with PE (10 vs. 50 months (0-152), P < 0.001 and 13 vs. 50 months (0-152), P < 0.001, respectively). For patients with stage II disease, DFS and OS were similarly decreased in pathologic nonresponders (13 vs. 62 months (0-120), P < 0.001 and 31 vs. 62 months (0-120), P = 0.024, respectively). There were no differences in DFS or OS for patients with stage III disease (10 vs. 14 months (0-152), P = 0.29 and 10 vs. 19 months (0-152), P = 0.16, respectively).

CONCLUSIONS

Pathologic nonresponders to NCRT for esophageal cancer receive no benefit in DFS or OS compared with patients treated with PE. For patients with stage II disease, DFS and OS are, in fact, significantly decreased in the pNR.

Correlation of tissue biopsy and fine needle aspiration cytology with positron emission tomography results

F-18-fluorodeoxyglucose (FDG) Positron Emission Tomography (PET) scans are positive in any condition which increases metabolism in a mass or tissue and are therefore not specific for neoplastic conditions. The use of an SUV cutoff value of 2.5 may not always help discriminate between benign and malignant cases. For a practicing cytopathologist doing adequacy checks during an image-guided procedure, it may be of value to be aware that elevated SUV values are not always indicative of a malignant process, and vice versa.

Outcomes of patients with esophageal cancer staged with [¹⁸F]fluorodeoxyglucose positron emission tomography (FDG-PET): can postchemoradiotherapy FDG-PET predict the utility of resection?

PURPOSE

To determine whether [(18)F]fluorodeoxyglucose positron emission tomography (FDG-PET) can delineate patients with esophageal cancer who may not benefit from esophagectomy after chemoradiotherapy.

PATIENTS AND METHODS

We reviewed records of 163 patients with histologically confirmed stage I to IVA esophageal cancer receiving chemoradiotherapy with or without resection with curative intent. All patients received surgical evaluation. Initial and postchemoradiotherapy FDG-PET scans and prognostic/treatment variables were analyzed. FDG-PET complete response (PET-CR) after chemoradiotherapy was defined as standardized uptake value ≤ 3.

RESULTS

Eighty-eight patients received trimodality therapy and 75 received chemoradiotherapy. Surgery was deferred primarily due to medical inoperability or unresectable/metastatic disease after chemoradiotherapy. A total of 105 patients were evaluable for postchemoradiotherapy FDG-PET response. Thirty-one percent achieved a PET-CR. PET-CR predicted for improved outcomes for chemoradiotherapy (2-year overall survival, 71% v 11%, P < .01; 2-year freedom from local failure [LFF], 75% v 28%, P < .01), but not trimodality therapy. On multivariate analysis of patients treated with chemoradiotherapy, PET-CR is the strongest independent prognostic variable (survival hazard ratio [HR], 9.82, P < .01; LFF HR, 14.13, P < .01). PET-CR predicted for improved outcomes regardless of histology, although patients with adenocarcinoma achieved a PET-CR less often.

CONCLUSION

Patients treated with trimodality therapy found no benefit with PET-CR, likely because FDG-PET residual disease was resected. Definitive chemoradiotherapy patients achieving PET-CR had excellent outcomes equivalent to trimodality therapy despite poorer baseline characteristics. Patients who achieve a PET-CR may not benefit from added resection given their excellent outcomes without resection. These results should be validated in a prospective trial of FDG-PET-directed therapy for esophageal cancer.

18-Fluorodeoxyglucose positron emission tomography as a tool for response prediction in solid tumours

Current response guidelines for the treatment of solid tumours are based on CT criteria. Over the last decades new techniques have emerged to evaluate cancer therapy. FDG-PET scanning is a more functional imaging technique, which can measure differences in metabolic activity. Although it has a low specificity, studies show that it can outperform classical CT scanning criteria. Especially in lung, breast and oesophageal cancer it can predict response earlier in the neo-adjuvant setting. This could reduce the use of ineffective cancer therapies, reducing costs and patient toxicity, and direct patients sooner towards effective therapy. The main problem with FDG-PET remains the difficulty in defining thresholds for response, as there is clearly a lack in large prospective randomized studies validating the use of FDG-PET in response guidelines.We give an overview of data on response prediction in solid tumours by the application of PET.