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

Advances in Diagnostic, Staging, and Restaging Evaluation of Esophageal and Gastric Cancer

The initial endoscopic and staging evaluation of esophagogastric cancers must be accurate and comprehensive in order to select the optimal therapeutic plan for the patient. Esophageal and gastric cancers (and treatment paradigms) are delineated by their proximity to the cardia (within 2 cm). The most frequent and important symptom that informs the initial staging evaluation is dysphagia, which is associated with at least cT3 or locally advanced disease. Endoscopic ultrasound is often needed if earlier stage disease is suspected, preferably in combination with endoscopic mucosal or submucosal resection or fine-needle aspiration of suspicious lymph nodes to enhance staging accuracy.

Can 18F-FDG PET/CT Radiomics Features Predict Clinical Outcomes in Patients with Locally Advanced Esophageal Squamous Cell Carcinoma?

Simple Summary

PET/CT is an important staging modality in the baseline assessment of locally advanced esophageal squamous cell carcinoma. Accurate staging and response prediction in these patients is essential for management. The aim of this retrospective study was to assess the usefulness of ¹⁸F-FDG PET/CT radiomics features in predicting outcomes such as tumor and nodal categories, PET-based response to induction chemotherapy, progression-free survival, and overall survival. In a final cohort of 74 patients, we found that the developed radiomics models can predict these clinical and prognostic outcomes with reasonable accuracy, similar or better than those derived from conventional imaging. Future studies with a larger cohort would be helpful in establishing the significance of these models.

Abstract

This study aimed to assess the usefulness of radiomics features of ¹⁸F-FDG PET/CT in patients with locally advanced esophageal cancers (ESCC) in predicting outcomes such as clinical tumor (cT) and nodal (cN) categories, PET response to induction chemotherapy (PET response), progression-free survival (PFS), and overall survival (OS). Pretreatment PET/CT images from patients who underwent concurrent chemoradiotherapy from July 2002 to February 2017 were segmented, and data were split into training and test sets. Model development was performed on the training datasets and a maximum of five features were selected. Final diagnostic accuracies were determined using the test dataset. A total of 86 PET/CTs (58 men and 28 women, mean age 65 years) were segmented. Due to small lesion size, 12 patients were excluded. The diagnostic accuracies as derived from the CT, PET, and combined PET/CT test datasets were as follows: cT category—70.4%, 70.4%, and 81.5%, respectively; cN category—69.0%, 86.2%, and 86.2%, respectively; PET response—60.0%, 66.7%, and 70.0%, respectively; PFS—60.7%, 75.0%, and 75.0%, respectively; and OS—51.7%, 55.2%, and 62.1%, respectively. A radiomics assessment of locally advanced ESCC has the potential to predict various clinical outcomes. External validation of these models would be further helpful.

Can 18F-FDG PET/CT Radiomics Features Predict Clinical Outcomes in Patients with Locally Advanced Esophageal Squamous Cell Carcinoma?

This study aimed to assess the usefulness of radiomics features of ¹⁸F-FDG PET/CT in patients with locally advanced esophageal cancers (ESCC) in predicting outcomes such as clinical tumor (cT) and nodal (cN) categories, PET response to induction chemotherapy (PET response), progression-free survival (PFS), and overall survival (OS). Pretreatment PET/CT images from patients who underwent concurrent chemoradiotherapy from July 2002 to February 2017 were segmented, and data were split into training and test sets. Model development was performed on the training datasets and a maximum of five features were selected. Final diagnostic accuracies were determined using the test dataset. A total of 86 PET/CTs (58 men and 28 women, mean age 65 years) were segmented. Due to small lesion size, 12 patients were excluded. The diagnostic accuracies as derived from the CT, PET, and combined PET/CT test datasets were as follows: cT category-70.4%, 70.4%, and 81.5%, respectively; cN category-69.0%, 86.2%, and 86.2%, respectively; PET response-60.0%, 66.7%, and 70.0%, respectively; PFS-60.7%, 75.0%, and 75.0%, respectively; and OS-51.7%, 55.2%, and 62.1%, respectively. A radiomics assessment of locally advanced ESCC has the potential to predict various clinical outcomes. External validation of these models would be further helpful.

Prognostic Significance of Interim Response Evaluation during Definitive Chemoradiotherapy for Locally Advanced Esophageal Squamous Cell Carcinoma

The study aimed to investigate the clinical significance of interim response evaluation during definitive chemoradiotherapy (dCRT) in predicting overall treatment response and survival of patients with locally advanced esophageal squamous cell carcinoma (LAESCC). We reviewed 194 consecutive patients treated with dCRT for biopsy-confirmed LAESCC. A total of 51 patients met the inclusion criteria. Interim response was assessed by defining a region of interest in initial and adaptive computed tomography (CT) images and subsequently examined against the overall treatment response assessed three months after dCRT, treatment failure pattern, overall survival (OS), and progression-free survival (PFS) estimates. Reductions in both the area and maximal diameter of the primary lesion (p < 0.001; p < 0.001, respectively) and those of the metastatic lymph nodes (LN) (p = 0.002; p < 0.001, respectively) in interim analysis were significantly higher among patients who achieved complete response (CR) than among those who did not. OS was significantly longer among patients who showed ≥30% interim reduction in the area and maximal diameter of the primary lesion and among those who showed such reduction in both the primary lesion and LN. PFS was significantly longer in the patients with ≥30% interim reduction in the area of the primary lesion. In addition, the proportion of cases with locoregional failure began decreasing at interim response of 20% or higher, while the proportion of cases with outfield failure followed the opposite pattern, increasing at interim response of 20% or higher. Among patients treated with dCRT for LAESCC, interim response assessed using adaptive CT images correlated with overall CR and OS rates. The evaluation of tumor burden reduction during dCRT may help predict patient prognosis.

Assessment of tumor response to definitive chemoradiotherapy and prognosis prediction in patients with esophageal cancer judged by PET response criteria in solid tumors: multicenter study in Japan

OBJECTIVES

The aim of the study was to evaluate PET response criteria in solid tumors (PERCIST) to indicate therapeutic response to definitive chemoradiotherapy, as well as prediction of recurrence and death in patients with esophageal cancer.

METHODS

Before and after recieving definitive chemoradiotherapy, 181 patients with esophageal cancer underwent fluorodeoxyglucose-PET/computed tomography (FDG-PET/CT). PERCIST, reduction rates of tumor uptake and volume of whole lesions, tumor node metastasis (TNM) staging regarding progression-free survival (PFS), and overall survival (OS) were analyzed using log-rank and Cox methods.

RESULTS

Complete metabolic response (CMR), partial metabolic response (PMR), stable metabolic disease (SMD), and progressive metabolic disease (PMD) shown by PERCIST were seen in 42 (23.2%), 113 (62.4%), 14 (7.7%), and 12 (6.6%) patients, respectively. Progression developed in 137 (75.7%) patients and 101 (56.1%) patients died (median follow-up 16.9, range 3.2-124.9 months). Those who achieved CMR showed significantly longer PFS and OS as compared with patients who did not (PMR, SMD, and PMD) (both P < 0.0001). In univariate analysis, initial clinical T status (P = 0.0048), N status (P = 0.011), and TNM stage (P = 0.0006), PERCIST (P < 0.0001), and reduction rate of peak lean body mass standardized uptake value (P < 0.0001), of metabolic tumor volume (P < 0.0001), and of total lesion glycolysis (TLG) (P < 0.0001) were associated with significantly increased OS. Multivariate analysis confirmed PERCIST [hazard ratio (HR): 13.15, 95% confidence interval (CI), 4.54-55.8; P < 0.0001], and TLG reduction rate (HR: 2.21, 95% CI, 1.04-4.68; P = 0.040) as independent OS predictors.

CONCLUSION

PERCIST is useful for evaluating therapeutic response to definitive chemoradiotherapy, and predicting progression and death in patients with esophageal cancer.

Artificial intelligence-assisted esophageal cancer management: Now and future

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

Prognostic value of lymph node to primary tumor standardized uptake value ratio in unresectable esophageal cancer

Background

Unresectable esophageal cancer harbors high mortality despite chemoradiotherapy. Better patient selection for more personalized management may result in better treatment outcomes. We presume the ratio of maximum standardized uptake value (SUV) of metastatic lymph nodes to primary tumor (NTR) in 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography/computed tomography (FDG PET/CT) may provide prognostic information and further stratification of these patients.

Methods

The patients with non-metastatic and unresectable esophageal squamous cell carcinoma (SCC) receiving FDG PET/CT staging and treated by chemoradiotherapy were retrospectively reviewed. Receiver operating characteristic (ROC) analysis was performed to determine the optimal cut-off value for NTR. Kaplan-Meier method and Cox regression model were used for survival analyses and multivariable analyses, respectively.

Results

From 2010 to 2016, 96 eligible patients were analyzed. The median follow-up time was 10.2 months (range 1.6 to 83.6 months). Using ROC analysis, the best NTR cut-off value was 0.46 for prediction of distant metastasis. The median distant metastasis-free survival (DMFS) was significantly lower in the high-NTR group (9.5 vs. 22.2 months, p = 0.002) and median overall survival (OS) (9.5 vs. 11.6 months, p = 0.013) was also significantly worse. Multivariable analysis revealed that NTR was an independent prognostic factor for DMFS (hazard ratio [HR] 1.81, p = 0.023) and OS (HR 1.77, p = 0.014).

Conclusions

High pretreatment NTR predicts worse treatment outcomes and could be an easy-to-use and helpful prognostic factor to provide more personalized treatment for patients with non-metastatic and unresectable esophageal SCC.

Benefits of positron emission tomography scans for the evaluation of radiotherapy

The assessment of tumour response during and after radiotherapy determines the subsequent management of patients (adaptation of treatment plan, monitoring, adjuvant treatment, rescue treatment or palliative care). In addition to its role in extension assessment and therapeutic planning, positron emission tomography combined with computed tomography provides useful functional information for the evaluation of tumour response. The objective of this article is to review published data on positron emission tomography combined with computed tomography as a tool for evaluating external radiotherapy for cancers. Data on positron emission tomography combined with computed tomography scans acquired at different times (during, after initial and after definitive [chemo-]radiotherapy, during post-treatment follow-up) in solid tumours (lung, head and neck, cervix, oesophagus, prostate and rectum) were collected and analysed. Recent recommendations of the National Comprehensive Cancer Network are also reported. Positron emission tomography combined with computed tomography with (¹⁸F)-labelled fluorodeoxyglucose has a well-established role in clinical routine after chemoradiotherapy for locally advanced head and neck cancers, particularly to limit the number of neck lymph node dissection. This imaging modality also has a place for the evaluation of initial chemoradiotherapy of oesophageal cancer, including the detection of distant metastases, and for the post-therapeutic evaluation of cervical cancer. Several radiotracers for positron emission tomography combined with computed tomography, such as choline, are also recommended for patients with prostate cancer with biochemical failure. (¹⁸F)-fluorodeoxyglucose positron emission tomography combined with computed tomography is optional in many other circumstances and its clinical benefits, possibly in combination with MRI, to assess response to radiotherapy remain a very active area of research.

Opportunistic body composition evaluation in patients with esophageal adenocarcinoma: association of survival with 18F-FDG PET/CT muscle metrics

OBJECTIVE

¹⁸F-FDG PET is widely used to accurately stage numerous types of cancers. Although ¹⁸F-FDG PET/CT features of tumors aid in predicting patient prognosis, there is increasing interest in mining additional quantitative body composition data that could improve the prognostic power of ¹⁸F-FDG PET/CT, without additional examination costs or radiation exposure. The aim of this study was to determine the association between overall survival and body composition metrics derived from routine clinical ¹⁸F-FDG PET/CT examinations.

METHODS

Patients who received baseline ¹⁸F-FDG PET/CT imaging during workup for newly diagnosed esophageal adenocarcinoma (EAC) were included. From these studies, psoas cross-sectional area (CSA), muscle attenuation (MA), SUV_mean, and SUV_max were obtained. Correlation with overall survival was assessed using a Cox Proportional Hazards model, controlling for age, body mass index, ¹⁸F-FDG dose, glucose level, diabetes status, in-hospital status, and tumor stage.

RESULTS

Among the 59 patients studied, psoas MA and SUV_max were found to be significant predictors of survival (HR 0.94, 95% CI 0.88-0.99, p = 0.04, and HR 0.37, 95% CI 0.14-0.97, p = 0.04, respectively) and remained independent predictors. Psoas CSA and SUV_mean did not significantly influence survival outcomes.

CONCLUSIONS

Characterization of psoas muscles as a surrogate marker for sarcopenia on baseline ¹⁸F-FDG PET/CT imaging is relatively easily obtained and may offer additional prognostic value in patients with EAC.

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.

Present and future roles of FDG-PET/CT imaging in the management of gastrointestinal cancer: an update

Positron emission tomography/computed tomography (PET/CT) integrated with 2-[¹⁸F]fluoro-2-deoxy-D-glucose (FDG) is a useful tool for acquisition of both glucose metabolism and anatomic imaging data, as only a single device and one diagnostic session is required, thus opening a new field in clinical oncologic imaging. FDG-PET/CT has been successfully used for initial staging, restaging, assessment of early treatment response, evaluation of metastatic disease response, and prognostication of intestinal cancer as well as various malignant tumors. We reviewed the current status and role of FDG-PET/CT for management of patients with esophageal cancer, gastric cancer, and colorectal cancer, with focus on both its usefulness and limitations.

Locally advanced gastro-oesophageal cancer: Recent therapeutic advances and research directions

Gastric (GC) and gastro-oesophageal (GOJC) adenocarcinomas are often considered as a single entity, even though differences exist in epidemiology, clinical presentation, molecular biology and treatment options. Locally advanced, resectable disease represents a particularly challenging scenario, as many critical issues need to be addressed. In both GC and GOJC among Western countries, systemic chemotherapy demonstrated the greatest benefit when administered before and after surgery and perioperative chemotherapy has been set as a standard in this setting. Nonetheless, multiple chemotherapy regimens have been tested and direct comparisons have been only recently presented. Adjuvant chemoradiotherapy is an option as well, but several trials have questioned its role when more effective combination regimens are used. With regards to GOJC, preoperative chemoradiotherapy is an alternative to perioperative chemotherapy, as it is associated with higher pathologic responses and a different toxicity profile: however, a definitive comparison with chemotherapy is ongoing. Herein, we review the current options for the treatment of resectable GC and GOJC and the main open questions in the management of these patients, trying to depict an update of the available algorithms for everyday practice. Moreover, we summarize the design and preliminary results of the randomized trials in progress that will hopefully give definitive answers to the most debated issues in the field.

Is pathological complete response after a trimodality therapy, a predictive factor of long-term survival in locally-advanced esophageal cancer? Results of a retrospective monocentric study

OBJECTIVE

To evaluate long-term (5- and 10-year) survival and recurrence rates on the basis of the pathological complete response (pCR) in the specimens of patients with esophageal carcinoma, treated with trimodality therapy.

METHODS

Between 1993 and 2014, all consecutives patients with esophageal locally-advanced non-metastatic squamous cell carcinoma (SCC) or adenocarcinoma (ADC) who received trimodality therapy were reviewed. According to histopathological analysis, patients were divided in two groups with pCR and with pathological residual tumor (pRT). The primary endpoint was overall survival (OS). The secondary endpoints included the disease-free survival (DFS), the recurrence rate, and the predictive factors of overall survival and recurrence.

RESULTS

One hundred and three patients were included: 49 patients with pCR and 54 patients with pRT. The median OS was significantly longer in pCR group than in pRT group (132±22.3 vs. 25.5±4 months), with both 5- and 10-years OS rates of 75.2% vs. 29.1%, and 51.1% vs. 13.6%, respectively (P<0.001). Also, pRT, major postoperative complications (Dindo-Clavien grade>IIIb) and recurrence were the 3 independent predictive factors for worse OS.

CONCLUSIONS

Patients with locally-advanced oesophageal carcinoma, who responded to trimodality therapy with a pCR, could be achieved a 10-year survival rate of 51%.

Early Metabolic Change after Induction Chemotherapy Predicts Histologic Response and Prognosis in Patients with Esophageal Cancer: Secondary Analysis of a Randomized Trial

BACKGROUND

Early metabolic response after preoperative induction chemotherapy (IC) appears to predict histologic response and prognosis in esophageal cancer (EC), but the usefulness of this approach needs further development.

OBJECTIVE

We evaluated metabolic response after one cycle of IC using positron emission tomography (PET) to correlate PET response and outcomes.

PATIENTS AND METHODS

We retrospectively analyzed PET data from a randomized phase 2 trial (NCT00525915) of chemoradiation and surgery with or without IC for the treatment of EC. PET was performed at baseline, after one cycle of IC, and 5-7 weeks after chemoradiation. The relationship between PET response (≥35% reduction in standardized uptake value [SUV]) after IC and treatment response was analyzed.

RESULTS

In 63 patients who received IC, the mean initial SUVmax prior to treatment was 11.9 ± 8.04 and mean SUVmax after one cycle of IC was 6.47 ± 4.45. The mean SUV reduction after IC was 39.3%. Eleven of 37 PET responders achieved a pathologic complete response (pCR), but only two of 22 PET non-responders did (univariate logistic regression; odds ratio: 4.25, 95% confidence interval: 0.83-21.77; p = 0.08). PET responders to IC had significantly longer overall survival (OS) than PET nonresponders (log-rank p = 0.009). PET response after chemoradiation was not correlated with OS (log-rank p = 0.15).

CONCLUSION

Early PET response after IC is prognostic, but subsequent PET changes (for example, after chemoradiation) are not prognostic. Early PET response might have the potential of predicting pCR.

Tumor regression grading of gastrointestinal cancers after neoadjuvant therapy

Neoadjuvant therapy has been successfully introduced in the treatment of locally advanced gastrointestinal malignancies, particularly esophageal, gastric, and rectal cancers. The effects of preoperative chemo- or radiochemotherapy can be determined by histopathological investigation of the resection specimen following this treatment. Frequent histological findings after neoadjuvant therapy include various amounts of residual tumor, inflammation, resorptive changes with infiltrates of foamy histiocytes, foreign body reactions, and scarry fibrosis. Several tumor regression grading (TRG) systems, which aim to categorize the amount of regressive changes after cytotoxic treatment in primary tumor sites, have been proposed for gastroesophageal and rectal carcinomas. These systems primarily refer to the amount of therapy-induced fibrosis in relation to the residual tumor (e.g., the Mandard, Dworak, or AJCC systems) or the estimated percentage of residual tumor in relation to the previous tumor site (e.g., the Becker, Rödel, or Rectal Cancer Regression Grading systems). TRGs provide valuable prognostic information, as in most cases, complete or subtotal tumor regression after neoadjuvant treatment is associated with better patient outcomes. This review describes the typical histopathological findings after neoadjuvant treatment, discusses the most commonly used TRG systems for gastroesophageal and rectal carcinomas, addresses the limitations and critical issues of tumor regression grading in these tumors, and describes the clinical impact of TRG.

Significance of baseline FDG-PET/CT scan as a method of staging regional lymph nodes in patients with operable distal oesophageal or gastroesophageal junction adenocarcinoma

BACKGROUND

The new American Joint Committee on Cancer eighth edition (AJCC8) staging is the first to describe separate clinical and pathology staging systems, but still has low performance to predict prognosis in patients with oesophageal/gastroesophageal junction (O/GOJ) adenocarcinoma, who are candidates for surgery. Recent studies have demonstrated that O/GOJ cancer patients with 18F-fluorodeoxyglucose (FDG) avid regional lymph nodes (RLNs) may have poor prognosis. The aim of our study was to examine whether the baseline assessment of the FDG uptake of RLN improves the prognostic accuracy of the new AJCC8 staging.

PATIENTS AND METHODS

This single-centre retrospective study included patients with operable FDG avid O/GOJ adenocarcinoma treated with perioperative chemotherapy. All patients were reclassified according to the new AJCC8 clinical staging. Prognostic factors for time-to-progression (TTP) and overall survival (OS) were explored.

RESULTS

Of 430 patients included in the study, 180 (41.9%) had FDG avid RLN at baseline PET/CT scan before starting perioperative chemotherapy. The presence of FDG avid RLN was significantly and independently associated with shorter TTP and OS, especially in clinical stage III patients (p < .001 in both cases). Stage III patients with FDG avid RLN had similar TTP and OS to those with stage IVA. Classifying stage III patients with FDG avid RLN into stage IVA led to a significant improvement of the prognostic accuracy of the new AJCC8 clinical staging system (Harrell's concordance index improved from 0.555 to 0.588, p < .001). Of 430 patients starting perioperative chemotherapy, 332 underwent radical tumour resection. The presence of FDG avid RLN before starting perioperative chemotherapy could additionally predict a significantly shorter postoperative time-to-relapse and OS (p < .001 in both cases).

CONCLUSIONS

We propose that the incorporation of RLN status (by FDG PET/CT scan) into the AJCC8 staging system of O/GOJ adenocarcinoma improves its prognostic accuracy and may also improve treatment stratification.

PET/Computed Tomography Scanning and Precision Medicine: Esophageal Cancer

Esophageal cancer commonly has a poor prognosis, which requires an accurate diagnosis and early treatment to improve outcome. Other modalities for staging, such as endoscopic ultrasound imaging and computed tomography (CT) scans, have a role in diagnosis and staging. However, PET with fluorine-18 fluoro-2-deoxy-d-glucose/CT (FDG PET/CT) scanning allows for improved detection of distant metastatic disease and can help to prevent unnecessary interventions that would increase morbidity. FDG PET/CT scanning is valuable in the neoadjuvant chemotherapy assessment and predicting survival outcomes subsequent to surgery. FDG PET/CT scanning detects recurrent disease and metastases in follow-up.

Prediction of disease-free survival using relative change in FDG-uptake early during neoadjuvant chemoradiotherapy for potentially curable esophageal cancer: A prospective cohort study

18F-Fluorodeoxyglucose positron emission tomography (FDG-PET) has been investigated as a tool for monitoring response to neoadjuvant chemo- and chemoradiotherapy (CT and CRT, respectively) and as a predictor for survival in patients with esophageal cancer. In contrast to patients who undergo neoadjuvant CT, it is not known whether patients who are clinically identified as responders after neoadjuvant CRT show better disease-free survival (DFS) than patients identified as nonresponders. The aim of the study was to determine the predictive value of FDG-uptake measured prior to and early during neoadjuvant CRT. Patients treated with neoadjuvant CRT between 2004 and 2009 within a randomized trial were included. FDG-uptake was measured at baseline and after 14 days of CRT. According to the PERCIST-criteria, patients were allocated to have metabolic response, stable disease, or progression. Patients were followed until recurrence of disease or death. The predictive value of FDG-PET was determined with univariable and multivariable analysis in patients who underwent potentially curative surgery. One-hundred and six patients were included in the analysis. Minimal follow-up for surviving patients was 60 months. No significant differences in DFS were found between patients with metabolic response, stable disease, or progression, with 5-year DFS rates of 66%, 53%, and 67%, respectively (P = 0.39). Relative change in FDG uptake after 14 days of CRT is not associated with DFS in patients with esophageal cancer undergoing neoadjuvant chemoradiotherapy followed by surgery. These measurements should not be used for prognostication in this specific group of patients.

Management of Locally Advanced Adenocarcinoma of the Esophagus and Gastroesophageal Junction: Finally a Consensus

Opinion statement: Adenocarcinoma of the esophagus is increasing in incidence in Western nations leading to increased interest in and opportunity to study optimal management. Randomized trials have now robustly demonstrated the preoperative therapy with chemoradiotherapy and chemotherapy alone improves survival outcome for the bulk of curable patients, those with locally advanced T1N1M0 and T2-3 N0-1 M0 disease. Evidence suggests but does not confirm that radiation-containing regimens are more beneficial. Clinical staging is designed to exclude patients with T1N0M0 disease who may be treated with surgery alone and those with metastatic disease who may not benefit from intensive local therapy. The approach to clinical staging includes endoscopy with ultrasound and fine needle aspirate to assess local and regional disease, supplemented by CT and PET scanning primarily to exclude metastatic disease. Minimally invasive approaches to esophagectomy may be used with the goal of reducing complications, but there is no evidence that mortality or ultimate outcome is improved.

PET-CT in the UK: current status and future directions

Combined positron-emission tomography and computed tomography (PET-CT) has taken the oncological world by storm since being introduced into the clinical domain in the early 21(st) century and is firmly established in the management pathway of many different tumour types. Non-oncological applications of PET-CT represent a smaller but steadily growing area of interest. PET-CT continues to be the focus of a large number of research studies and keeping up-to-date with the literature is important but represents a challenge. Consequently guidelines recommending PET-CT usage need to be revised regularly to encompass new developments. The purpose of this article is twofold: first, it provides a detailed review of the evidence-base underpinning the major uses of PET-CT in clinical practice, which may be of value to a wide-range of individuals, including those directly involved with PET-CT and to a much larger group with limited exposure, but for whom a précis of the current state-of-play may help inform other radiology and multidisciplinary team (MDT) work; the second purpose is as a companion to revised guidelines on evidence-based indications for PET-CT in the UK (being published concurrently) providing a detailed commentary on new indications with a summary of emerging data supporting these additional clinical uses of the technique.

Relationship between the Temporal Changes in Positron-Emission-Tomography-Imaging-Based Textural Features and Pathologic Response and Survival in Esophageal Cancer Patients

PURPOSE

Although change in standardized uptake value (SUV) measures and PET-based textural features during treatment have shown promise in tumor response prediction, it is unclear which quantitative measure is the most predictive. We compared the relationship between PET-based features and pathologic response and overall survival with the SUV measures in esophageal cancer.

METHODS

Fifty-four esophageal cancer patients received PET/CT scans before and after chemoradiotherapy. Of these, 45 patients underwent surgery and were classified into complete, partial, and non-responders to the preoperative chemoradiation. SUVmax and SUVmean, two cooccurrence matrix (Entropy and Homogeneity), two run-length matrix (RLM) (high-gray-run emphasis and Short-run high-gray-run emphasis), and two size-zone matrix (high-gray-zone emphasis and short-zone high-gray emphasis) textures were computed. The relationship between the relative difference of each measure at different treatment time points and the pathologic response and overall survival was assessed using the area under the receiver-operating-characteristic curve (AUC) and Kaplan-Meier statistics, respectively.

RESULTS

All Textures, except Homogeneity, were better related to pathologic response than SUVmax and SUVmean. Entropy was found to significantly distinguish non-responders from the complete (AUC = 0.79, p = 1.7 × 10(-4)) and partial (AUC = 0.71, p = 0.01) responders. Non-responders can also be significantly differentiated from partial and complete responders by the change in the run-length and size-zone matrix textures (AUC = 0.71-0.76, p ≤ 0.02). Homogeneity, SUVmax, and SUVmean failed to differentiate between any of the responders (AUC = 0.50-0.57, p ≥ 0.46). However, none of the measures were found to significantly distinguish between complete and partial responders with AUC <0.60 (p = 0.37). Median Entropy and RLM textures significantly discriminated patients with good and poor survival (log-rank p < 0.02), while all other textures and survival were poorly related (log-rank p > 0.25).

CONCLUSION

For the patients studied, temporal changes in Entropy and all RLM were better correlated with pathological response and survival than the SUV measures. The hypothesis that these metrics can be used as clinical predictors of better patient outcomes will be tested in a larger patient dataset in the future.

Prognostic significance of (18)F-FDG PET at diagnosis in patients with soft tissue sarcoma and bone sarcoma; systematic review and meta-analysis

PURPOSE

The usefulness of (18)F-fluorodeoxyglucose positron emission tomography ((18)F-FDG PET) for the survival prognosis in soft tissue sarcoma (STS) and bone sarcoma (BS) is controversial. The objective of this systematic review was to provide an up-to-date and unprecedented summary of the prognostic value of (18)F-FDG PET at diagnosis in STS and BS.

METHODS

Studies evaluating pre-treatment (18)F-FDG PET for overall survival of STS and BS were systematically searched for in MEDLINE, EMBASE, and Web of Science. Comparative analyses of the pooled hazard ratios (HR) of overall survival were performed between patients with high and low maximum standardised uptake value (SUVmax). The quality of study designs was evaluated using the Newcastle-Ottawa scale (NOS) for quality assessment of cohort studies. P < 0.05 was defined as statistically significant.

RESULTS

A total of six studies comprising 514 patients with STS and BS were considered for the meta-analysis. The pooled HR for overall survival was 1.22 (95% confidence interval: 1.03-1.46), suggesting that high SUVmax predicts a significantly shorter overall survival period than low SUVmax (P = 0.03). Additional subgroup analyses using patients with STS alone showed that high SUVmax might predict poorer overall survival than low SUVmax (P = 0.004), although only two studies consisting of 96 patients were included. The overall quality of the included studies evaluated by the NOS assessment was adequate.

CONCLUSION

(18)F-FDG PET at diagnosis provides a very useful predictive tool for patients with STS and BS.

Molecular Imaging to Plan Radiotherapy and Evaluate Its Efficacy

Molecular imaging plays a central role in the management of radiation oncology patients. Specific uses of imaging, particularly to plan radiotherapy and assess its efficacy, require an additional level of reproducibility and image quality beyond what is required for diagnostic imaging. Specific requirements include proper patient preparation, adequate technologist training, careful imaging protocol design, reliable scanner technology, reproducible software algorithms, and reliable data analysis methods. As uncertainty in target definition is arguably the greatest challenge facing radiation oncology, the greatest impact that molecular imaging can have may be in the reduction of interobserver variability in target volume delineation and in providing greater conformity between target volume boundaries and true tumor boundaries. Several automatic and semiautomatic contouring methods based on molecular imaging are available but still need sufficient validation to be widely adopted. Biologically conformal radiotherapy (dose painting) based on molecular imaging-assessed tumor heterogeneity is being investigated, but many challenges remain to fully exploring its potential. Molecular imaging also plays increasingly important roles in both early (during treatment) and late (after treatment) response assessment as both a predictive and a prognostic tool. Because of potentially confounding effects of radiation-induced inflammation, treatment response assessment requires careful interpretation. Although molecular imaging is already strongly embedded in radiotherapy, the path to widespread and all-inclusive use is still long. The lack of solid clinical evidence is the main impediment to broader use. Recommendations for practicing physicians are still rather scarce. (18)F-FDG PET/CT remains the main molecular imaging modality in radiation oncology applications. Although other molecular imaging options (e.g., proliferation imaging) are becoming more common, their widespread use is limited by lack of tracer availability and inadequate reimbursement models. With the increasing presence of molecular imaging in radiation oncology, special emphasis should be placed on adequate training of radiation oncology personnel to understand the potential, and particularly the limitations, of quantitative molecular imaging applications. Similarly, radiologists and nuclear medicine specialists should be sensitized to the special need of the radiation oncologist in terms of quantification and reproducibility. Furthermore, strong collaboration between radiation oncology, nuclear medicine/radiology, and medical physics teams is necessary, as optimal and safe use of molecular imaging can be ensured only within appropriate interdisciplinary teams.

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

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

Is there a role for PET/CT with esophagogastric junction adenocarcinoma?

The value of 18F-FDG PET/CT in the initial diagnosis and in the locoregional staging of esophagogastric junction adenocarcinoma is not fully established. However, 18F-FDG PET/CT is widely accepted as the best modality for identification of suspected metastases in staging of the disease. Results published in the literature suggest that 18F-FDG PET/CT may provide useful information for response assessment to neoadjuvancy and to differentiate responding and nonresponding tumors. We review the potential role of 18F-FDG PET/CT imaging in staging, restaging, and prognostic value after chemoradiation therapy in esophagogastric junction adenocarcinoma.

Change in volume parameters induced by neoadjuvant chemotherapy provide accurate prediction of overall survival after resection in patients with oesophageal cancer

OBJECTIVES

To assess the prognostic value of volumetric parameters measured with CT and PET/CT in patients with neoadjuvant chemotherapy (NACT) and resection for oesophageal cancer (EC).

METHODS

Patients with locally advanced EC, who were treated with NACT and resection, were retrospectively analysed. Data from CT volumetry and (18) F-FDG PET/CT (maximum standardized uptake [SUVmax], metabolic tumour volume [MTV], and total lesion glycolysis [TLG]) were recorded before and after NACT. The impact of volumetric parameter changes induced by NACT (MTVRATIO, TLGRATIO, etc.) on overall survival (OS) was assessed using a Cox proportional hazards model.

RESULTS

Eighty-four patients were assessed using CT volumetry; of those, 50 also had PET/CT before and after NACT. Low post-treatment CT volume and thickness, MTV, TLG, and SUVmax were all associated with longer OS (p < 0.05), as were CTthicknessRATIO, MTVRATIO, TLGRATIO, and SUVmaxRATIO (p < 0.05). In the multivariate analysis, only MTVRATIO (Hazard ratio, HR 2.52 [95% Confidence interval, CI 1.33-4.78], p = 0.005), TLGRATIO (HR 3.89 [95%CI 1.46-10.34], p = 0.006), and surgical margin status (p < 0.05), were independent predictors of OS.

CONCLUSIONS

MTVRATIO and TLGRATIO are independent prognostic factors for survival in patients after NACT and resection for EC.

KEY POINTS

• Change in PET parameters shows close correlation to survival in oesophageal cancer. • Association with OS is independent of changes in SUVmax and CT volume. • Metabolic parameters after NACT correlate with pathologic response and nodal status. • Metabolic parameters may be better suited than SUVmax for response assessment.

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.

Highlights of the 26th EANM 2013 congress in Lyon: new horizons and further

The 26th European Association of Nuclear Medicine (EANM) annual congress was held in Lyon, France, under the chairmanship of Professor Dominique LeGuludec. The congress was attended by more than 5,200 participants, with about one-quarter coming from outside Europe. This review summarizes the major scientific contributions which were selected from the more than 1,700 submitted abstracts, and presented in the closing highlights session. They covered the diverse areas of nuclear medicine, with particular focus on oncology, cardiovascular science and neurology. Various innovations were reported regarding imaging methodology, physics, radiopharmaceuticals and chemistry. Novel radionuclide applications in both diagnosis and therapy were investigated and described, triggering strong interest from the many professionals involved. Significant progress has been demonstrated in the clinical use of existing nuclear medicine procedures, and a number of new applications are under development in preclinical and early clinical stages. The congress was a unique opportunity to get a thorough update on this research.