Johannes B. Roedl

Adenocarcinomas of the esophagus: response to chemoradiotherapy is associated with decrease of metabolic tumor volume as measured on PET-CT. Comparison to histopathologic and clinical response evaluation.

PURPOSEnWe determined whether evaluation of treatment response is feasible by measuring metabolic tumor volume parameters on 18F-FDG (Fluorodeoxyglucose) PET-CT (Positron emission tomography-Computed tomography). We compared the response evaluation based on metabolic tumor volume parameters to a histopathologic and clinical response evaluation (clinical response criteria: RECIST criteria=Response evaluation criteria in solid tumors, and WHO criteria=World health organization).nnnPATIENTS AND METHODSnA total of 51 study subjects with adenocarcinomas (Type I due to Siewert classification) of the esophagus underwent PET-CT scans before and after neoadjuvant chemoradiotherapy. Tumor volume, maximum and mean standardized uptake values (SUV) were assessed before and after chemoradiotherapy. Furthermore, the total lesion glycolysis (TLG) was calculated by multiplying the tumor volume by the mean SUV of the volume. Clinical response evaluation was performed with endoscopic ultrasound and CT using RECIST and WHO criteria. The reference standard for treatment response was the postsurgical histopathology.nnnRESULTSnThe decrease of tumor volume between the pre- and post-treatment PET-CT scans was a better predictor of histopathologic response and survival than the decrease of the SUV and of the clinical response evaluation based on RECIST and WHO criteria. The highest accuracy, however, was achieved when using the TLG for the identification of treatment responders. A decrease of the TLG by > 78% between pre- and post-therapy scans predicted histopathologic response with a sensitivity and specificity of 91% and 93%, respectively.nnnCONCLUSIONSnTumor volume and TLG can be used to assess treatment response and survival in patients with esophageal adenocarcinoma.

Metabolic Tumor Width Parameters as Determined on PET/CT Predict Disease-free Survival and Treatment Response in Squamous Cell Carcinoma of the Esophagus

Materials and MethodsWe investigated the utility of metabolic tumor width parameters in predicting response to chemoradiotherapy and in predicting disease-free survival in patients with esophageal cancer. Furthermore, we evaluated the possible confounding effect of therapy-induced esophagitis on the evaluation of treatment response. Forty-nine patients with squamous cell carcinoma, who had undergone positron emission tomography/computed tomography (PET/CT) exams before and after neoadjuvant chemoradiotherapy, were included in the study. In the slice with the maximum 2-deoxy-2-[F-18]fluoro-d-glucose (FDG) uptake of the tumor, the following metabolic tumor width parameters were measured: Area of the tumor, maximum diameter of the tumor, maximum and mean standardized uptake value (SUV). Furthermore, the “diameter-SUV index” was calculated by multiplying the tumor diameter by the mean SUV.ResultsThe decrease of the metabolic tumor diameter between pre- and post-treatment PET/CT scans was the single best predictor of treatment response and tumor-free survival. However, the accuracy of predicting response and survival was even higher when using the decrease of the “diameter-SUV index” as the metabolic criterion for treatment response. A decrease by more than 55% of the diameter-SUV index identified pathologic responders (nu2009=u200922) with a sensitivity of 91% and a specificity of 93%. Radiation esophagitis was found to have a significant impact on the assessment of treatment response when evaluating therapy response based on the maximum SUV, whereas no confounding effect of radiation esophagitis was seen when evaluating therapy response based on the tumor diameter or the diameter-SUV index.ConclusionThe present study shows that tumor width parameters, especially the tumor diameter or the combination of diameter and SUV in the “diameter-SUV index”, are valuable for predicting tumor-free survival and treatment response independent from the presence of radiation esophagitis.

Assessment of Treatment Response and Recurrence in Esophageal Carcinoma Based on Tumor Length and Standardized Uptake Value on Positron Emission Tomography–Computed Tomography

BACKGROUNDnPrevious studies demonstrated that a decrease of the standardized uptake value between pretreatment and posttreatment positron emission tomography (PET) scans can predict histopathologic treatment response in patients with esophageal cancer.nnnMETHODSnForty-seven patients who underwent PET-computed tomography (CT) scans before (scan 1) and after (scan 2) neoadjuvant chemoradiotherapy and during the follow-up period after surgery (scan 3) were included in this study. It was evaluated whether decrease of metabolic tumor length between scan 1 and scan 2 can predict histopathologic response to treatment. Moreover, the value of PET-CT was compared with PET in the assessment of tumor recurrence based on a visual analysis of scan 3. Reference standards for treatment response and recurrence were histopathology results.nnnRESULTSnThe reduction of tumor length between before and after chemoradiotherapy scans (between scan 1 and scan 2) was a better predictor of histopathologic response and of time to recurrence than the decrease in standardized uptake value. The most accurate differentiation was achieved when using a cut-off value of 33% reduction of the initial tumor length. Using this threshold to define metabolic response, the sensitivity was 91% (19 of 21) and the specificity was 92% (24 of 26) for predicting histopathologic treatment response. Based on a visual analysis, PET-CT was more accurate than PET in the differentiation of tumor recurrence from posttreatment tissue changes. Integrated PET-CT achieved a sensitivity of 91% (48 of 53) and a specificity of 81% (30 of 37) in identifying sites of tumor recurrence, compared with 83% (44 of 53) and 65% (24 of 37) with PET.nnnCONCLUSIONSnDecrease of tumor length was shown to be a better predictor of treatment response and disease-free survival than decrease of standardized uptake value. Furthermore, PET-CT is more accurate in the evaluation of recurrence than PET.

Visual PET/CT Scoring for Nonspecific 18F-FDG Uptake in the Differentiation of Early Malignant and Benign Esophageal Lesions

OBJECTIVEnThe purpose of our study was to evaluate a visual PET/CT scoring system for the differentiation of benign and early malignant esophageal uptake.nnnMATERIALS AND METHODSnThirty-six consecutive patients with precancerous or early malignant esophageal lesions including Barretts esophagus, Tis, T1, and T2 adenocarcinomas were eligible. Findings of these patients were compared with 66 patients who had reported increased esophageal (18)F-FDG uptake due to benign esophageal disorders. Lesions were evaluated with scores using the following characteristics in PET/CT: FDG uptake intensity (low = 0, moderate = 1, high = 2), FDG uptake eccentricity (concentric = 0, eccentric = 1), FDG uptake focality (diffuse = 0, segmental = 1, focal = 2), esophageal thickness on the CT component (normal = 0, thickening = 1, mass = 2), and location (distal third of the esophagus = 0, middle third of the esophagus = 1, proximal third of the esophagus = 2).nnnRESULTSnEarly malignant lesions had higher scores in FDG uptake intensity (p = 0.003; chi-square), eccentricity (p < 0.001), and focality (p < 0.001) compared with benign lesions. No significant difference was seen in esophageal thickness on CT (p = 0.168) and in location of the lesion (p = 0.291). Binary logistic regression analysis with a stepwise forward inclusion of all score components including the maximum standardized uptake value (SUV) of the lesions revealed that a total score combining eccentricity and focality scores has the highest accuracy of predicting early malignant disease. Using a threshold of equal or higher than 2 in the combined total focality-eccentricity score, the sensitivity was 83.3% and specificity was 68.2% for predicting early malignant disease.nnnCONCLUSIONnFocality and eccentricity of FDG uptake prove to be valuable PET/CT characteristics for the differentiation of nonspecific FDG uptake in the esophagus.

Tumour length measured on PET-CT predicts the most appropriate stage-dependent therapeutic approach in oesophageal cancer

To compare the accuracy of determining the most appropriate treatment approach based on a visual analysis on combined PET-CT, based on a visual analysis on PET (reviewed side-by-side with CT) and based on tumour length measurements (on PET and PET-CT). Tumour length, SUV, and the length-SUV index (length × SUV) were assessed (on PET and PET-CT) in benign oesophageal lesions (reflux oesophagitis; nu2009=u200929), in potentially curable stages of oesophageal cancer (Tis; T1-T3NxM0; curable group; nu2009=u200952), and in stages of oesophageal cancer best treated with palliative therapy (T4NxMx; TxNxM1; palliative group; nu2009=u200930). All lesions were histopathologically proven. Based on a visual analysis, PET-CT (sensitivity: 77%;specificity: 96%) was more accurate than PET (sensitivity: 67%; specificity: 89%) in assessing the appropriate treatment (curative vs. palliative). The length-SUV index was the most accurate quantitative parameter to distinguish palliative from curable stages (sensitivity: 93%; specificity: 90%) and to predict survival. The highest overall accuracy was reached when combining the results of the quantitative (length-SUV index) analysis with those of the qualitative (visual) analysis (sensitivity: 93%; specificity: 96%). Moreover, neither tumour length nor SUV can be used to distinguish reflux oesophagitis from early malignant lesions (T1 stage). Tumour length measured with PET-CT or PET is associated with stage and overall survival of oesophageal cancer and helps to guide the appropriate treatment approach.

Prediction of Metastatic Disease and Survival in Patients with Gastric and Gastroesophageal Junction Tumors: The Incremental Value of PET-CT over PET and the Clinical Role of Primary Tumor Volume Measurements

RATIONALE AND OBJECTIVESnTo investigate the accuracy of M staging (staging of metastatic disease) in esophageal carcinoma based on a visual interpretation and based on tumor volume measurements on positron emission tomography (PET) computed tomography (CT).nnnMATERIALS AND METHODSnFifty-nine untreated patients with gastroesophageal junction tumors were enrolled, including 36 subcardial gastric tumors (type III according to Siewert classification) and 23 adenocarcinomas of the cardia (AEG, type II Siewert). Patients were grouped in metastasis free (M0 stage, n = 34) and metastatic stages (M1 stage, n = 25). Tumor volume and mean and maximum standardized uptake value were measured on PET-CT. The accuracy of these quantitative tumor volume parameters in distinguishing metastasis-free tumors (M0 stage) from metastatic stages (M1 stage) was compared to the accuracy of a visual analysis with fused PET-CT. Furthermore, accuracy of PET-CT was compared to PET reviewed side by side with CT in a lesion-based analysis of 84 distant metastatic sites.nnnRESULTSnIn the visual interpretation, PET-CT (accuracy 88%, 74/84) was more accurate than PET (accuracy 78%, 66/84; P = .008) in characterizing the 84 potential metastatic sites in the 59 patients. Among the tumor parameters, the PET-CT tumor volume was the most accurate predictor of M1 stage and overall survival. With a threshold of 39 mL, PET-CT volume was able to predict M1 stage disease with a sensitivity of 96% and a specificity of 85%. The accuracy of M-staging was increased further when combining tumor volume measurements with the results from the visual analysis (combined results: sensitivity 96%, specificity 94%).nnnCONCLUSIONSnPET-CT was more accurate than PET (reviewed side by side with CT) in characterizing distant metastatic sites of gastroesophageal junction carcinomas. The highest accuracy for M-staging was obtained when combining the results of the visual analysis with the results from primary tumor volume measurements. Primary tumor volume was shown to be an independent prognostic factor.

Lymph node staging in esophageal adenocarcinoma with PET-CT based on a visual analysis and based on metabolic parameters

BackgroundIn order to investigate the value of FDG positron emission tomography-computed tomography (PET-CT), FDG PET (reviewed side-by-side with CT), and metabolic parameters in the assessment of lymph node status and prognosis.MethodsFifty-five subjects with lymph node positive (N1) and 26 subjects with lymph node negative (N0) disease were included. In the slice with the maximum FDG uptake of the tumor, the axial area of the primary tumor, the maximum diameter of the tumor, and the mean and maximum standardized uptake values were measured.ResultsFused PET-CT correctly characterized 289 of 325 lymph node groups (accuracy 89%) compared to 273 of 325 with PET (accuracy 84%). In lymph node staging (N0 vs. N1), PET-CT (accuracy 83%) was more accurate than PET (accuracy 78%). Among the metabolic parameters, the tumor diameter measured on PET-CT was the best predictor of lymph node stage (N0 vs. N1: accuracy 86%; threshold 25.5xa0mm) and overall survival. However, the highest accuracy of lymph node staging (N0 vs. N1) was achieved with the synergistic combination of visual analysis and primary tumor diameter measurements (accuracy 95%).ConclusionsPET-CT increases accuracy of lymph node staging in esophageal adenocarcinoma compared to PET. The primary tumor diameter further improves accuracy in lymph node staging and was shown to be an independent predictor of overall survival.