PET/CT-based metabolic tumour volume for response prediction of neoadjuvant chemoradiotherapy in oesophageal carcinoma

Correlation of primary tumor volume and histopathologic response following neoadjuvant treatment of esophageal adenocarcinoma

INTRODUCTION

In esophageal cancer, histopathologic response following neoadjuvant therapy and transthoracic esophagectomy is a strong predictor of long-term survival. At the present, it is not known whether the initial tumor volume quantified by computed tomography (CT) correlates with the degree of pathologic regression.

METHODS

In a retrospective analysis of a consecutive patient cohort with esophageal adenocarcinoma, tumor volume in CT prior to chemoradiotherapy or chemotherapy alone was quantified using manual segmentation. Primary tumor volume was correlated to the histomorphological regression based on vital residual tumor cells (VRTC) (Cologne regression scale, CRS: grade I, >50% VRTC; grade II, 10-50% VRTC; grade III, <10% VRTC and grade IV, complete response without VRTC).

RESULTS

A total of 287 patients, 165 with neoadjuvant chemoradiotherapy according to the CROSS protocol and 122 with chemotherapy according to the FLOT regimen, were included. The initial tumor volume for patients following CROSS and FLOT therapy was measured (CROSS: median 24.8 ml, IQR 13.1-41.1 ml, FLOT: 23.4 ml, IQR 10.6-37.3 ml). All patients underwent an Ivor-Lewis esophagectomy. 180 patients (62.7 %) were classified as minor (CRS I/II) and 107 patients (37.3 %) as major or complete responder (CRS III/IV). The median tumor volume was calculated as 24.2 ml (IQR 11.9-40.3 ml). Ordered logistic regression revealed no significant dependence of CRS from tumor volume (OR = 0.99, p-value = 0.99) irrespective of the type of multimodal treatment.

CONCLUSION

The initial tumor volume on diagnostic CT does not aid to differentiate between potential histopathological responders and non-responders to neoadjuvant therapy in esophageal cancer patients. The results emphasize the need to establish other biological markers of prediction.

Accurate Preoperative Evaluation of the Location of Esophagogastric Junction Adenocarcinoma Using Positron Emission Tomography-Computed Tomography

BACKGROUND

The surgical procedure for esophagogastric junction (EGJ) adenocarcinoma usually depends on the location of its epicenter or proximal margin, but accurate evaluation of these positions is often difficult. The usefulness of positron emission tomography-computed tomography (PET-CT) for this purpose is unknown.

METHODS

Between June 2005 and February 2015, we enrolled 30 patients with cT2-4 EGJ adenocarcinoma (Siewert type I/II) who underwent surgical resection. We ascertained the sensitivity and specificity of preoperative PET-CT for identifying the primary tumor and regional lymph node metastasis, and compared PET-CT and pathological findings in terms of the distance from the EGJ to the tumor epicenter or proximal tumor margin.

RESULTS

PET-CT detected the primary tumor with a sensitivity of 97% (29/30), and detected lymph node metastasis with a sensitivity and specificity of 22% (4/18) and 100% (8/8), respectively. No significant association was observed between the maximal standardized uptake value and histological type, tumor size, or pT status. Regarding the accuracy of evaluating tumor location, the median differences between PET-CT and pathological measurements were .6 cm for the tumor epicenter and .5 cm for the proximal margin from the EGJ. PET-CT and pathological findings showed agreement regarding Siewert classification type (I or II) and lengths of esophageal involvement exceeding 4 cm or 2 cm in 77% (10/13), 85% (11/13), and 85% (11/13) of cases, respectively.

DISCUSSION

PET-CT had high sensitivity for primary EGJ adenocarcinoma. It may effectively locate the tumor epicenter and proximal margin and thus help clinicians determine the optimal surgical procedure.

Pretreatment 18F-FDG PET/CT-Derived Parameters in Predicting Clinical Outcomes of Locally Advanced Upper Third Esophageal Squamous Cell Carcinoma After Definitive Chemoradiation Therapy

Purpose

The aim of this study was to investigate whether standard uptake values (SUVs) of pretreatment ¹⁸F-FDG PET/CT were the surrogate parameters for predicting the outcomes in locally advanced esophageal squamous cell carcinoma patients treated with definitive chemoradiotherapy.

Materials and Methods

Sixty patients with esophageal squamous cell carcinoma underwent pretreatment ¹⁸F-FDG PET/CT and received definitive chemoradiotherapy. ¹⁸F-FDG metabolic parameters including SUVmax, SUVmean, SULpeak, total lesion glycolysis (TLG), and metabolic tumor volume (MTV) of primary tumor were calculated. The receiver-operating characteristic (ROC) curve was used to determine the optimal cutoff value of FDG PET/CT-derived parameters that associated with treatment response. Estimating progression-free survival (PFS) and overall survival (OS) was analyzed by using Kaplan-Meier methods. Univariate and multivariate analysis for PFS and OS was performed using Cox regression.

Results

Complete response was achieved in 38.3%. The 4-year OS and PFS rates were 48.6% and 44.4%, respectively. SUVmean with a cutoff value of 6.1 could predict complete response with sensitivity of 69.6%, specificity of 78.4%, and accuracy of 75%. Cox multi-factor regression analyses revealed SUVmean > 6.1 as an independent prognostic factor for OS (HR = 6.74, p = 0.02) and PFS (HR = 6.53, p < 0.001).

Conclusions

Our study suggests that SUVmean of the primary tumor in pretreatment ¹⁸F-FDG PET/CT may be used as an independent predictor in esophageal squamous cell carcinoma patients treated with definitive chemoradiotherapy.

Tumor Stage-Based Gross Tumor Volume of Resectable Esophageal Squamous Cell Carcinoma Measured on CT: Association With Early Recurrence After Esophagectomy

Objective

To investigate relationship of tumor stage-based gross tumor volume (GTV) of esophageal squamous cell carcinoma (ESCC) measured on computed tomography (CT) with early recurrence (ER) after esophagectomy.

Materials and Methods

Two hundred and four consecutive patients with resectable ESCC including 159 patients enrolled in the training cohort (TC) and 45 patients in validation cohort (VC) underwent contrast-enhanced CT less than 2 weeks before esophagectomy. GTV was retrospectively measured by multiplying sums of all tumor areas by section thickness. For the TC, univariate and multivariate analyses were performed to determine factors associated with ER. Mann-Whitney U test was conducted to compare GTV in patients with and without ER. Receiver operating characteristic (ROC) analysis was performed to determine if tumor stage-based GTV could predict ER. For the VC, unweighted Cohen’s Kappa tests were used to evaluate the performances of the previous ROC predictive models.

Results

ER occurred in 63 of 159 patients (39.6%) in the TC. According to the univariate analysis, histologic differentiation, cT stage, cN stage, and GTV were associated with ER after esophagectomy (all P-values < 0.05). Multivariate analysis revealed that cT stage and GTV were independent risk factors with hazard ratios of 3.382 [95% confidence interval (CI): 1.533–7.459] and 1.222 (95% CI: 1.125–1.327), respectively (all P-values < 0.05). Mann-Whitney U tests showed that GTV could help differentiate between ESCC with and without ER in stages cT_1-4a, cT₂, and cT₃ (all P-values < 0.001), and the ROC analysis demonstrated the corresponding cutoffs of 13.31, 17.22, and 17.83 cm³ with areas under the curve of more than 0.8, respectively. In the VC, the Kappa tests validated that the ROC predictive models had good performances for differentiating between ESCC with and without ER in stages cT_1-4a, cT₂, and cT₃ with Cohen k of 0.696 (95% CI, 0.498–0.894), 0.733 (95% CI, 0.386–1.080), and 0.862 (95% CI, 0.603–1.121), respectively.

Conclusion

GTV and cT stage can be independent risk factors of ER in ESCC after esophagectomy, and tumor stage-based GTV measured on CT can help predict ER.

Radiomics in the Setting of Neoadjuvant Radiotherapy: A New Approach for Tailored Treatment

Simple Summary

This review based on a literature search aims at showing the impact of Texture Analysis in the prediction of response to neoadjuvant radiotherapy and/or chemoradiotherapy. The manuscript explores radiomics approaches in different fields of neoadjuvant radiotherapy, including esophageal cancer, lung cancer, sarcoma and rectal cancer in order to shed a light in the setting of neoadjuvant radiotherapy that can be used to tailor the best subsequent therapeutical strategy.

Abstract

Introduction: Neoadjuvant radiotherapy is currently used mainly in locally advanced rectal cancer and sarcoma and in a subset of non-small cell lung cancer and esophageal cancer, whereas in other diseases it is under investigation. The evaluation of the efficacy of the induction strategy is made possible by performing imaging investigations before and after the neoadjuvant therapy and is usually challenging. In the last decade, texture analysis (TA) has been developed to help the radiologist to quantify and identify the parameters related to tumor heterogeneity, which cannot be appreciated by the naked eye. The aim of this narrative is to review the impact of TA on the prediction of response to neoadjuvant radiotherapy and or chemoradiotherapy. Materials and Methods: Key references were derived from a PubMed query. Hand searching and ClinicalTrials.gov were also used. Results: This paper contains a narrative report and a critical discussion of radiomics approaches in different fields of neoadjuvant radiotherapy, including esophageal cancer, lung cancer, sarcoma, and rectal cancer. Conclusions: Radiomics can shed a light on the setting of neoadjuvant therapies that can be used to tailor subsequent approaches or even to avoid surgery in the future. At the same, these results need to be validated in prospective and multicenter trials.

Intratumoral Metabolic Heterogeneity and Other Quantitative 18F-FDG PET/CT Parameters for Prognosis Prediction in Esophageal Cancer

PURPOSE

To evaluate the impact of intratumoral metabolic heterogeneity (IMH) and other quantitative fluorine 18 (¹⁸F) fluorodeoxyglucose (FDG) PET/CT parameters for predicting progression-free survival (PFS) and overall survival (OS) in patients with esophageal cancer.

MATERIALS AND METHODS

In this retrospective study, an automated gradient-based segmentation method was used to assess the maximum standardized uptake value, mean standardized uptake value, metabolic tumor volume (MTV), and IMH index of the primary tumor in patients with biopsy-proven adenocarcinoma or squamous cell carcinoma of the esophagus with an initial staging ¹⁸F-FDG PET/CT. Data were collected between July 2006 and February 2016. OS and PFS were calculated using multivariable Cox proportional hazards regression with the adjustment (as covariates) of age, sex, weight, stage, tumor type, tumor grade, and treatment. All PET parameters were standardized before analysis. Log-rank tests were performed, and corresponding Kaplan-Meier survival plots were generated.

RESULTS

A total of 71 patients (mean age, 64 years ± 10 [standard deviation], 62:9 men:women) were included. Median follow-up time was 28.2 months (range, 4-38 months), and median survival was 16.1 months (range, 0.1-60.3 months). Higher MTV was associated with reduced PFS for every standard deviation increase (hazard ratio [HR], 0.193; 95% CI: 0.052, 0.711; P = .01). Higher IMH was associated with reduced PFS for every standard deviation decrease in the area under the curve (HR, 10.78; 95% CI: 1.31, 88.96; P = .03).

CONCLUSION

PFS for patients with esophageal cancer was associated with MTV and with IMH.Keywords: Esophagus, Neoplasms-Primary, PET/CT, Tumor Response © RSNA, 2020.

Assessment of Intratumoral and Peritumoral Computed Tomography Radiomics for Predicting Pathological Complete Response to Neoadjuvant Chemoradiation in Patients With Esophageal Squamous Cell Carcinoma

IMPORTANCE

For patients with locally advanced esophageal squamous cell carcinoma, neoadjuvant chemoradiation has been shown to improve long-term outcomes, but the treatment response varies among patients. Accurate pretreatment prediction of response remains an urgent need.

OBJECTIVE

To determine whether peritumoral radiomics features derived from baseline computed tomography images could provide valuable information about neoadjuvant chemoradiation response and enhance the ability of intratumoral radiomics to estimate pathological complete response.

DESIGN, SETTING, AND PARTICIPANTS

A total of 231 patients with esophageal squamous cell carcinoma, who underwent baseline contrast-enhanced computed tomography and received neoadjuvant chemoradiation followed by surgery at 2 institutions in China, were consecutively included. This diagnostic study used single-institution data between April 2007 and December 2018 to extract radiomics features from intratumoral and peritumoral regions and established intratumoral, peritumoral, and combined radiomics models using different classifiers. External validation was conducted using independent data collected from another hospital during the same period. Radiogenomics analysis using gene expression profile was done in a subgroup of the training set for pathophysiological explanation. Data were analyzed from June to December 2019.

EXPOSURES

Computed tomography-based radiomics.

MAIN OUTCOMES AND MEASURES

The discriminative performances of radiomics models were measured by area under the receiver operating characteristic curve.

RESULTS

Among the 231 patients included (192 men [83.1%]; mean [SD] age, 59.8 [8.7] years), the optimal intratumoral and peritumoral radiomics models yielded similar areas under the receiver operating characteristic curve of 0.730 (95% CI, 0.609-0.850) and 0.734 (0.613-0.854), respectively. The combined model was composed of 7 intratumoral and 6 peritumoral features and achieved better discriminative performance, with an area under the receiver operating characteristic curve of 0.852 (95% CI, 0.753-0.951), accuracy of 84.3%, sensitivity of 90.3%, and specificity of 79.5% in the test set. Gene sets associated with the combined model mainly involved lymphocyte-mediated immunity. The association of peritumoral area with response identification might be partially attributed to type I interferon-related biological process.

CONCLUSIONS AND RELEVANCE

A combination of peritumoral radiomics features appears to improve the predictive performance of intratumoral radiomics to estimate pathological complete response after neoadjuvant chemoradiation in patients with esophageal squamous cell carcinoma. This study underlines the significant application of peritumoral radiomics to assess treatment response in clinical practice.

Prognostic value of SUR in patients with trimodality treatment of locally advanced esophageal carcinoma

The prognosis of patients with esophageal carcinoma remains dismal despite ongoing efforts to improve treatment options. For locally advanced tumors, several randomized trials have shown the benefit of neoadjuvant chemoradiation followed by surgery compared to surgery alone. The aim of this exploratory study was to evaluate the prognostic value of different baseline positron emission tomography (PET) parameters and their potentially additional prognostic impact at the end of neoadjuvant radiochemotherapy. Furthermore, the standard uptake ratio (SUR) as a new parameter for quantification of tumor metabolism was compared to the conventional PET parameters metabolic active volume (MTV), total lesion glycolysis (TLG), and standardized uptake value (SUV) taking into account known basic parameters. Methods:18F-FDG-PET/CT was performed in 76 consecutive patients ((60±10) years, 71 males) with newly diagnosed esophageal cancer before and during the last week of neoadjuvant radiochemotherapy. MTV of the primary tumor was delineated with an adaptive threshold method. The blood SUV was determined by manually delineating the aorta in the low dose CT. SUR values were computed as scan time corrected ratio of tumor SUVmax and mean blood SUV. Univariate Cox regression and Kaplan-Meier analysis with respect to locoregional control (LRC), freedom from distant metastases (FFDM), and overall survival (OS) was performed. Additionally, independence of PET parameters from standard clinical factors was analyzed with multivariate Cox regression. Results: In multivariate analysis two parameters showed a significant correlation with all endpoints: restaging MTV and restaging SUR. Furthermore, restaging TLG was prognostic for LCR and FFDM. For all endpoints the largest effect size was found for restaging SUR. The only basic factors remaining significant in multivariate analyses were histology for OS and FFDM and age for LRC. Conclusion: PET provides independent prognostic information for OS, LRC, and FFDM in addition to standard clinical parameters in this patient cohort. Our results suggest that the prognostic value of tracer uptake can be improved when characterized by SUR rather than by SUV. Overall, our investigation revealed a higher prognostic value of restaging parameters compared to baseline PET; therapy-adjustments would still be possible at this point of time. Further investigations are required to confirm these hypothesis-generating results.

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

Purpose

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

Patients and methods

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

Results

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

Conclusion

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

Personalized therapy based on image for esophageal or gastroesophageal junction adenocarcinoma

Preoperative therapy is the gold standard for esophageal or gastroesophageal junction adenocarcinoma. Positron emission tomography (PET) is not only essential for tumor staging, but changes in glucose consumption correspond with response to therapy and correlated with prognosis. Therefore, with further refinement, PET parameter can serve as a tool for personalized therapy. For instance, the Municon trials suggested the possibility of PET-response guided therapy for esophageal adenocarcinoma (EAC) patients, however there are limitations. New PET parameters such as total lesion glycolysis (TLG) or magnetic resonance imaging (MRI) may provide better response prediction. Furthermore, PET parameters combined with genomic profiling might enhance better treatment selection, prediction, and prognostication. Here, we summarized the current state of understanding and future possibilities.

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.

Predictive value of initial FDG-PET features for treatment response and survival in esophageal cancer patients treated with chemo-radiation therapy using a random forest classifier

Purpose

In oncology, texture features extracted from positron emission tomography with 18-fluorodeoxyglucose images (FDG-PET) are of increasing interest for predictive and prognostic studies, leading to several tens of features per tumor. To select the best features, the use of a random forest (RF) classifier was investigated.

Methods

Sixty-five patients with an esophageal cancer treated with a combined chemo-radiation therapy were retrospectively included. All patients underwent a pretreatment whole-body FDG-PET. The patients were followed for 3 years after the end of the treatment. The response assessment was performed 1 month after the end of the therapy. Patients were classified as complete responders and non-complete responders. Sixty-one features were extracted from medical records and PET images. First, Spearman’s analysis was performed to eliminate correlated features. Then, the best predictive and prognostic subsets of features were selected using a RF algorithm. These results were compared to those obtained by a Mann-Whitney U test (predictive study) and a univariate Kaplan-Meier analysis (prognostic study).

Results

Among the 61 initial features, 28 were not correlated. From these 28 features, the best subset of complementary features found using the RF classifier to predict response was composed of 2 features: metabolic tumor volume (MTV) and homogeneity from the co-occurrence matrix. The corresponding predictive value (AUC = 0.836 ± 0.105, Se = 82 ± 9%, Sp = 91 ± 12%) was higher than the best predictive results found using the Mann-Whitney test: busyness from the gray level difference matrix (P < 0.0001, AUC = 0.810, Se = 66%, Sp = 88%). The best prognostic subset found using RF was composed of 3 features: MTV and 2 clinical features (WHO status and nutritional risk index) (AUC = 0.822 ± 0.059, Se = 79 ± 9%, Sp = 95 ± 6%), while no feature was significantly prognostic according to the Kaplan-Meier analysis.

Conclusions

The RF classifier can improve predictive and prognostic values compared to the Mann-Whitney U test and the univariate Kaplan-Meier survival analysis when applied to several tens of features in a limited patient database.

The application of positron emission tomography (PET/CT) in diagnosis of breast cancer. Part II. Diagnosis after treatment initiation, future perspectives

Similarly to the applications described in the first part of this publication, positron emission tomography with computed tomography (PET/CT) is also gaining importance in monitoring a tumour's response to therapy and diagnosing breast cancer recurrences. This is additionally caused by the fact that many new techniques (dual-time point imaging, positron emission tomography with magnetic resonance PET/MR, PET/CT mammography) and radiotracers (16α-18F-fluoro-17β-estradiol, 18F-fluorothymidine) are under investigation. The highest sensitivity and specificity when monitoring response to treatment is achieved when the PET/CT scan is made after one or two chemotherapy courses. Response to anti-hormonal treatment can also be monitored, also when new radiotracers, such as FES, are used. When monitoring breast cancer recurrences during follow-up, PET/CT has higher sensitivity than conventional imaging modalities, making it possible to monitor the whole body simultaneously. New techniques and radiotracers enhance the sensitivity and specificity of PET and this is why, despite relatively high costs, it might become more widespread in monitoring response to treatment and breast cancer recurrences.

A Role for Tumor Volume Assessment in Resectable Esophageal Cancer

BACKGROUND

Esophageal cancer has a poor prognosis, and many patients undergoing surgery have a low chance of cure. Imaging studies suggest that tumor volume is prognostic. The study aimed to evaluate pathological tumor volume (PTV) as a prognostic variable in esophageal cancer.

METHODS

This single-center cohort study included 283 patients who underwent esophageal cancer resections between 2000 and 2012. PTVs were obtained from pathological measurements using a validated volume formula. The prognostic value of PTV was analyzed using multivariable regression models, adjusting for age, tumor grade, tumor (T) stage, nodal stage, lymphovascular invasion, resection margin, resection type, and chemotherapy response, which provided hazard ratios (HRs) with 95 % confidence intervals (CIs). Primary outcomes were time to death and time to recurrence. Secondary outcomes were margin involvement and lymph node positivity. Correlation analysis was performed between imaging and PTVs.

RESULTS

On unadjusted analysis, increasing PTV was associated with worse overall mortality (HR 2.30, 95 % CI 1.41-3.73) and disease recurrence (HR 1.87, 95 % CI 1.14-3.07). Adjusted analysis demonstrated worse overall mortality with increasing PTV but reached significance in only one subgroup (HR 1.70, 95 % CI 1.09-2.38). PTV was an independent predictor of margin involvement (OR 2.28, 95 % CI 1.02-5.13) and lymph node-positive status (OR 2.77, 95 % CI 1.23-6.28). Correlation analyses demonstrated significant positive correlation between computed tomography (CT) software and formula tumor volumes (r = 0.927, p < 0.0001), CT and positron emission tomography tumor volumes (r = 0.547, p < 0.0001), and CT and PTVs (r = 0.310, p < 0.001).

CONCLUSIONS

Tumor volume may predict survival, margin status, and lymph node positivity after surgery for esophageal cancer.

Application of novel quantitative techniques for fluorodeoxyglucose positron emission tomography/computed tomography in patients with non-small-cell lung cancer

AIM

Flurodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) is routinely used in non-small-cell lung cancer. This study aims to assess the prognostic value of quantitative FDG-PET/CT parameters including standard uptake value (SUV), metabolic tumor volume (MTV) and total lesional glycolysis (TLG) in non-small-cell lung cancer.

METHODS

A retrospective review of 92 nonsurgical patients with pathologically confirmed stage I-III non-small-cell lung cancers treated with radical dose radiotherapy (≥50 Gy) was conducted. Metabolically active tumor regions on FDG-PET/CT scans were contoured manually. SUV, MTV and TLG were calculated for primary, nodal and whole-body disease. Univariate and multivariate (adjusting for age, sex, disease stage and primary tumor size in centimeters) Cox regression modeling were performed to assess the association between these parameters and both overall and progression-free survival (PFS).

RESULTS

On univariate analysis, overall survival (OS) was significantly associated with primary MTV (P = 0.03), whole-body MTV (P = 0.02), whole-body maximum SUV (P = 0.05) and whole-body TLG (P = 0.03). PFS was significantly associated with primary MTV (P = 0.01), primary TLG (P = 0.04), whole-body MTV (P < 0.01) and whole-body TLG (P = 0.01). On multivariate analysis, OS was significantly associated with whole-body MTV (P = 0.05). PFS was significantly associated with whole-body MTV (P = 0.02) and whole-body TLG (P = 0.05).

CONCLUSIONS

Whole-body MTV was significantly associated with overall and PFS, and whole-body TLG was significantly associated with PFS on multivariate analysis. These two parameters may be significant prognostic factors independent of other factors such as stage. SUV was not significantly associated with survival on multivariate analysis.

The emerging field of radiomics in esophageal cancer: current evidence and future potential

'Radiomics' is the name given to the emerging field of extracting additional information from standard medical images using advanced feature analysis. This innovative form of quantitative image analysis appears to have future potential for clinical practice in patients with esophageal cancer by providing an additional layer of information to the standard imaging assessment. There is a growing body of evidence suggesting that radiomics may provide incremental value for staging, predicting treatment response, and predicting survival in esophageal cancer, for which the current work-up has substantial limitations. This review outlines the available evidence and future potential for the application of radiomics in the management of patients with esophageal cancer. In addition, an overview of the current evidence on the importance of reproducibility of image features and the substantial influence of varying smoothing scales, quantization levels, and segmentation methods is provided.

A study about different findings of PET-CT between neoadjuvant and non-neoadjuvant therapy: SUVmax is not a reliable predictor of lymphatic involvement after neoadjuvant therapy for esophageal cancer

BACKGROUND

No definitive findings or established guidelines have been published for the evaluation of esophageal tumors (tumor) and regional lymph nodes (LN) using positron emission tomography computed tomography (PET-CT) in patients with esophageal cancer. In addition, it remains unclear whether PET-CT findings vary between neoadjuvant (NT) and non-neoadjuvant (non-NT) therapy cases. Therefore, preoperative evaluation using PET-CT might provide unreliable information and influence the management plan for esophageal cancer. The purpose of the present study is to clarify the different findings of PET-CT between NT and non-NT in surgical esophageal cancer cases and to predict LN metastasis.

METHODS

We retrospectively reviewed the medical records of 192 consecutive cases that met this study's inclusion criteria from January 2009 to December 2014. All patients underwent curative and complete esophagectomy for intra-thoracic esophageal cancer at the department of thoracic and cardiovascular surgery in a single tertiary Korean hospital. We compiled and analyzed maximum standard uptake values (SUVmax) of tumor and LNs with other clinical information (chronic lung disease, history of previous other primary cancer, sex, pathological findings, NT, and other clinical data).

RESULTS

(I) In NT, a positive correlation between T stage and SUVmax was found (tumor SUVmax P<0.001, LN SUVmax P=0.010); however, no relationship between N stage and SUVmax was found. In non-NT, a positive correlation between pathological stage (T and N stage) and SUVmax was found (T stage, tumor SUVmax P<0.001, LN SUVmax P=0.001; N stage, tumor SUVmax P=0.003, LN SUVmax P=0.021); (II) In NT, the low SUVmax group had higher disease-free survival (DFS) and overall survival (OS) than the high SUVmax group (DFS, tumor SUVmax P<0.001, LN SUVmax P=0.142; OS, tumor SUVmax P<0.001, LN SUVmax P=0.002). In non-NT, the low SUVmax group also had higher DFS and OS than the high SUVmax group (DFS, tumor SUVmax P<0.001, LN SUVmax P=0.008; OS, tumor SUVmax P=0.029, LN SUVmax P=0.016). SUVmax values being equal, non-NT had significantly higher DFS and OS than NT (P=0.011, P=0.009, respectively), despite the absence of significant differences in pathological stage; (III) Tumor SUVmax had a positive correlation with LN SUVmax in both NT and non-NT (P=0.006, P<0.001, respectively); (IV) In NT, there were no diagnostic findings of LN metastases using SUVmax. However, in non-NT, significant cutoff values for diagnosis of LN metastases using both tumor and LN SUVmax were found (tumor SUVmax cutoff value 4.9, P=0.008; LN SUVmax cutoff value 2.5, P=0.045); (V) In NT, there was no significant difference in LN SUVmax between pathologically negative and positive LNs. However, in non-NT, the LN SUVmax of pathologically positive LNs was significantly higher than that of pathologically negative LNs (P=0.042); (VI) There were no significant differences in tumor and LN SUVmax according to various factors, including chronic lung disease (COPD, bronchiectasis), age, previous cancers, and sex, regardless of NT.

CONCLUSIONS

This study showed that there were some different findings of PET-CT using SUVmax between NT and non-NT. These findings should be clarified for further evaluation and management, especially of surgery, which should not be withheld out of ignorance of these different PET-CT findings and should be considered carefully in conjunction with other conditions. In addition, further studies about the effects of NT on PET-CT findings are required to improve the utility of PET-CT to evaluate the LNs in esophageal cancer.

Endoscopic biopsy and EUS for the detection of pathologic complete response after neoadjuvant chemoradiotherapy in esophageal cancer: a systematic review and meta-analysis

BACKGROUND AND AIMS

Accurate determination of residual cancer status after neoadjuvant chemoradiotherapy (nCRT) for esophageal cancer could assist in selecting the optimal treatment strategy. The aim of this study was to review the evidence on the diagnostic accuracy of endoscopic biopsy and EUS after nCRT for detecting residual cancer at the primary tumor site (ypT+) and regional lymph nodes (ypN+) as opposed to a pathologic complete response (ypT0 and ypN0).

METHODS

PubMed/Medline, Embase, and the Cochrane library were systematically searched. The analysis included diagnostic studies reporting on the accuracy of endoscopic biopsy or EUS in detecting residual cancer versus complete response after nCRT for esophageal cancer with histopathology as the reference standard. Bivariate random-effects models were used to estimate pooled sensitivities and specificities and examine sources of heterogeneity.

RESULTS

Twenty-three studies comprising 12 endoscopic biopsy studies (1281 patients), 11 EUS studies reporting on ypT status (593 patients), and 10 EUS studies reporting on ypN status (602 patients), were included. Pooled estimates for sensitivity of endoscopic biopsy after nCRT for predicting ypT+ were 34.5% (95% confidence interval [CI], 26.0%-44.1%) and for specificity 91.0% (95% CI, 85.6%-94.5%). Pooled estimates for sensitivity of EUS after nCRT were 96.4% (95% CI, 91.7%-98.5%) and for specificity were 10.9% (95% CI, 3.5%-29.0%) for detecting ypT+, and 62.0% (95% CI, 46.0%-75.7%) and 56.7% (95% CI, 41.8%-70.5%) for detecting ypN+, respectively.

CONCLUSIONS

Endoscopic biopsy after nCRT is a specific but not sensitive method for detecting residual esophageal cancer. Although EUS after nCRT yields a high sensitivity, only a limited number of patients will have negative findings at EUS with still a substantial false-negative rate. Furthermore, EUS provides only moderate accuracy for detecting residual lymph node involvement. Based on these findings, these endoscopic modalities cannot be used to withhold surgical treatment in test-negative patients after nCRT. (

CLINICAL TRIAL REGISTRATION NUMBER

CRD42015016527.).

Association between the inflammatory biomarker, C-reactive protein, and the response to radiochemotherapy in patients with esophageal cancer

Locally advanced esophageal cancer has been treated by a multimodality regimen encompassing combined radiochemotherapy (RCT). The tumor response to neoadjuvant RCT is a major determinant of further therapeutic strategies, whether surgery or a continuation of RCT, and therefore, also of the patient's overall prognosis. The present study included patients with histologically proven squamous cell esophageal carcinoma. The C-reactive protein (CRP) level was measured prior to and following the completion of neoadjuvant RCT. Only CRP measurements taken within 2 weeks of the start of RCT were analyzed. Further measurements were then taken at 6, 12, 18, 24, 30, 36 and 40 weeks following RCT. CRP levels were high prior to treatment; however, eventually decreased and normalized following the therapy. In univariate analysis, pre-therapeutic CRP levels had a significant influence on the response rate (P=0.033), whilst post-therapeutic CRP levels had no significant influence (P=0.383). Pre-therapeutic CRP levels, however, not post-therapeutic CRP levels were significantly correlated with the response rate (P=0.045 and P=0.444, respectively), and no association was observed between CRP levels and survival. This preliminary data indicated that the pre-therapeutic serum CRP level is a possible indicator of treatment response to RCT.

The Incremental Value of Subjective and Quantitative Assessment of 18F-FDG PET for the Prediction of Pathologic Complete Response to Preoperative Chemoradiotherapy in Esophageal Cancer

A reliable prediction of a pathologic complete response (pathCR) to chemoradiotherapy before surgery for esophageal cancer would enable investigators to study the feasibility and outcome of an organ-preserving strategy after chemoradiotherapy. So far no clinical parameters or diagnostic studies are able to accurately predict which patients will achieve a pathCR. The aim of this study was to determine whether subjective and quantitative assessment of baseline and postchemoradiation (18)F-FDG PET can improve the accuracy of predicting pathCR to preoperative chemoradiotherapy in esophageal cancer beyond clinical predictors.

METHODS

This retrospective study was approved by the institutional review board, and the need for written informed consent was waived. Clinical parameters along with subjective and quantitative parameters from baseline and postchemoradiation (18)F-FDG PET were derived from 217 esophageal adenocarcinoma patients who underwent chemoradiotherapy followed by surgery. The associations between these parameters and pathCR were studied in univariable and multivariable logistic regression analysis. Four prediction models were constructed and internally validated using bootstrapping to study the incremental predictive values of subjective assessment of (18)F-FDG PET, conventional quantitative metabolic features, and comprehensive (18)F-FDG PET texture/geometry features, respectively. The clinical benefit of (18)F-FDG PET was determined using decision-curve analysis.

RESULTS

A pathCR was found in 59 (27%) patients. A clinical prediction model (corrected c-index, 0.67) was improved by adding (18)F-FDG PET-based subjective assessment of response (corrected c-index, 0.72). This latter model was slightly improved by the addition of 1 conventional quantitative metabolic feature only (i.e., postchemoradiation total lesion glycolysis; corrected c-index, 0.73), and even more by subsequently adding 4 comprehensive (18)F-FDG PET texture/geometry features (corrected c-index, 0.77). However, at a decision threshold of 0.9 or higher, representing a clinically relevant predictive value for pathCR at which one may be willing to omit surgery, there was no clear incremental value.

CONCLUSION

Subjective and quantitative assessment of (18)F-FDG PET provides statistical incremental value for predicting pathCR after preoperative chemoradiotherapy in esophageal cancer. However, the discriminatory improvement beyond clinical predictors does not translate into a clinically relevant benefit that could change decision making.

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

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

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.

Usefulness of positron emission tomography-computed tomography in pre-operative evaluation of intra-thoracic esophageal cancer

Background

The purpose of the study was to clarify the usefulness of positron emission tomography-computed tomography (PET-CT) for pre-operative evaluation of intra-thoracic esophageal cancer, especially in terms of regional lymph node status.

Methods

Medical records of 93 consecutive cases from July 2007 to October 2012 were retrospectively reviewed. All patients underwent curative and complete esophagectomies for intra-thoracic esophageal cancer. We compared pre-operative maximum standard uptake values (SUVmax) of esophageal tumors and regional lymph nodes (LN) with other variables (chronic obstructive pulmonary disease, history of previous other primary cancer, gender, differentiation, and neoadjuvant therapy). In addition, the SUVmax of tumors and LNs were analyzed with pathologic findings.

Results

There was no significant difference of each tumor and LN SUVmax according to factors including chronic lung disease, age, history of previous other cancer, differentiation, and gender. Pre-operative evaluations by PET-CT were not accurate (tumor sensitivity 76.4%, specificity 25%; LN sensitivity 45.2%, specificity 54.8%). Receiver operating characteristic analysis showed that LN metastasis could not be appropriately diagnosed with SUVmax (P = 0.871). There was no difference in SUVmax between pathologically positive and negative LN subgroups. Tumor SUVmax correlated with the progression of esophageal cancer in patients without neoadjuvant therapy (P < 0.001). However, LN SUVmax had no correlation with overall pathologic stage. After neoadjuvant therapy, there were significant decreases in SUVmax in both pathologically positive and negative LN subgroups (P = 0.043, P = 0.008).

Conclusion

 Surgery should not be withheld in N-stage according to PET-CT findings and carefully considered in conjunction with other conditions.

Induction chemotherapy followed by surgery for advanced oesophageal cancer

BACKGROUND

Patients with locoregionally advanced oesophageal tumours or disputable distant metastases are referred for induction chemotherapy with the aim to downstage the tumour before an oesophagectomy is considered.

STUDY DESIGN

Patients who underwent induction chemotherapy between January 2005 and December 2012 were identified from an institutional database. Treatment plan was discussed in the multidisciplinary team. Response to chemotherapy was assessed by CT. Survival was calculated using the Kaplan Meier method. Uni- and multivariable analyses were performed to identify prognostic factors for survival.

RESULTS

In total 124 patients received induction chemotherapy mainly for locoregionally advanced disease (n = 80). Surgery was withheld in 35 patients because of progressive disease (n = 16) and persistent unresectability (n = 19). The median overall survival of this group was 13 months (IQR: 8-19). The remaining 89 patients underwent surgery of which 13 still had unresectable tumour or distant metastases. Of the 76 patients that underwent an oesophagectomy, 50 patients had tumour free resection margins (66%) with an estimated 5-year survival of 37%. A positive resection margin (HR 4.148, 95% CI 2.298-7.488, p < 0.0001) was associated with a worse survival in univariable analysis, but only pathological lymph node status with increasing hazard ratio's (6.283-10.283, p = 0.001) remained significant after multivariable analysis.

CONCLUSION

Induction chemotherapy downstages the tumour and facilitates a radical oesophagectomy in patients with advanced oesophageal cancer. Pathological lymph node status is an independent prognostic factor for overall survival.