18FDG uptake in oesophageal adenocarcinoma: linking biology and outcome

Evaluation of the 18F-FDG-PET/CT uptake association with pathological and immunohistochemistry features in esophagogastric adenocarcinoma

BACKGROUND

The present study aimed to analyze the association between 18F-fluorodeoxyglucose (FDG) uptake and histologic panel in esophagogastric adenocarcinoma.

METHODS

We retrospectively enrolled 26 patients with histologically confirmed esophageal, gastroesophageal junction and gastric adenocarcinoma that have been submitted to pretreatment FDG-PET/CT. We collected the cancer tissue sample of each patient and performed immunohistochemical analyses of the glucose transport protein 1 (GLUT-1), Ki-67, cysteine aspartate-specific proteinases (Caspase)-3 and hexokinase-1, and evaluated the association of these parameters with FDG uptake. The FDG uptake was measured by tumor standardized uptake value (SUV), metabolic tumor volume (MTV), and Total Lesion Glycolysis (TLG). Besides, we analyzed the association of FDG uptake and tumor location, Lauren's histologic subtype, grade of cellular differentiation and intratumoral inflammatory infiltrate.

RESULTS

We found a positive association between GLUT-1 with SUV and TLG, Caspase-3 and SUV and inflammation grade with SUV.

CONCLUSION

Tumor inflammation infiltrate, GLUT-1 and Caspase-3 correlated with 18F-FDG uptake in PET/CT in esophagogastric adenocarcinoma. These findings may help understand the pathologic PET/CT significance in cancer. Understanding the meaning of the 18F-FDG uptake in the field of tumor histologic and immunohistochemistry features is essential to allow the evolution of PET/CT application in esophageal and gastric carcinomas.

Radiogenomic analysis of primary breast cancer reveals [18F]-fluorodeoxglucose dynamic flux-constants are positively associated with immune pathways and outperform static uptake measures in associating with glucose metabolism

BACKGROUND

PET imaging of 18F-fluorodeoxygucose (FDG) is used widely for tumour staging and assessment of treatment response, but the biology associated with FDG uptake is still not fully elucidated. We therefore carried out gene set enrichment analyses (GSEA) of RNA sequencing data to find KEGG pathways associated with FDG uptake in primary breast cancers.

METHODS

Pre-treatment data were analysed from a window-of-opportunity study in which 30 patients underwent static and dynamic FDG-PET and tumour biopsy. Kinetic models were fitted to dynamic images, and GSEA was performed for enrichment scores reflecting Pearson and Spearman coefficients of correlations between gene expression and imaging.

RESULTS

A total of 38 pathways were associated with kinetic model flux-constants or static measures of FDG uptake, all positively. The associated pathways included glycolysis/gluconeogenesis ('GLYC-GLUC') which mediates FDG uptake and was associated with model flux-constants but not with static uptake measures, and 28 pathways related to immune-response or inflammation. More pathways, 32, were associated with the flux-constant K of the simple Patlak model than with any other imaging index. Numbers of pathways categorised as being associated with individual micro-parameters of the kinetic models were substantially fewer than numbers associated with flux-constants, and lay around levels expected by chance.

CONCLUSIONS

In pre-treatment images GLYC-GLUC was associated with FDG kinetic flux-constants including Patlak K, but not with static uptake measures. Immune-related pathways were associated with flux-constants and static uptake. Patlak K was associated with more pathways than were the flux-constants of more complex kinetic models. On the basis of these results Patlak analysis of dynamic FDG-PET scans is advantageous, compared to other kinetic analyses or static imaging, in studies seeking to infer tumour-to-tumour differences in biology from differences in imaging. Trial registration NCT01266486, December 24th 2010.

Usefulness of Hybrid PET/MRI in Clinical Evaluation of Head and Neck Cancer Patients

(1) Background: The novel hybrid of positron emission tomography/magnetic resonance (PET/MR) examination has been introduced to clinical practice. The aim of our study was to evaluate PET/MR usefulness in preoperative staging of head and neck cancer (HNC) patients (pts); (2) Methods: Thirty eight pts underwent both computed tomography (CT) and PET/MR examination, of whom 21 pts underwent surgical treatment as first-line therapy and were further included in the present study. Postsurgical tissue material was subjected to routine histopathological (HP) examination with additional evaluation of p16, human papillomavirus (HPV), Epstein-Barr virus (EBV) and Ki67 status. Agreement of clinical and pathological T staging, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) of CT and PET/MR in metastatic lymph nodes detection were defined. The verification of dependences between standardized uptake value (SUV value), tumor geometrical parameters, number of metastatic lymph nodes in PET/MR and CT, biochemical parameters, Ki67 index, p16, HPV and EBV status was made with statistical analysis of obtained results; (3) Results: PET/MR is characterized by better agreement in T staging, higher specificity, sensitivity, PPV and NPV of lymph nodes evaluation than CT imaging. Significant correlations were observed between SUVmax and maximal tumor diameter from PET/MR, between SUVmean and CT tumor volume, PET/MR tumor volume, maximal tumor diameter assessed in PET/MR. Other correlations were weak and insignificant; (4) Conclusions: Hybrid PET/MR imaging is useful in preoperative staging of HNC. Further studies are needed.

A review on immunohistochemical and histopathologic validation in PET-CT findings with consideration to microRNAs

Purpose

This review provides an overview of some of the most recent clinical trials which investigated various types of cancer and other diseases, through the use of PET-CT imaging, highlighting the use of immunohistochemical stains or conventional histopathology for the validation or contradiction of their hypothesis. Furthermore, we investigate a potential new direction of research by analyzing the upcoming role of microRNAs in disease confirmation.

Methods

An extensive search of MEDLINE/PubMed and SCOPUS electronic databases was made, using the MeSH terms "positron emission tomography computed tomography" and "immunohistochemistry" as well as "SUV" and "immunohistochemistry", restricting the search by clinical trials and time period. Further searches were made for articles regarding Ki-67 and microRNAs in correlation with metabolic PET-CT uptake.

Results

Out of all 389 initial search results, 27 original articles were found relevant to the topic. Their contents were synthesized and discussed regarding the matter at hand. No relevant clinical trials involving microRNAs were found.

Conclusions

Immunohistochemical and histopathologic results remain widely used and indispensable in modern research, concerning PET-CT validation. Possible candidates for diagnosis confirmation, in future research, may reside in the further development of microRNAs.

18F-FDG-PET Can Predict Microvessel Density in Head and Neck Squamous Cell Carcinoma

Aim: Positron emission tomography (PET) with ¹⁸F-fluordeoxyglucose (¹⁸F-FDG) plays an essential role in the staging and tumor monitoring of head and neck squamous cell carcinoma (HNSCC). Microvessel density (MVD) is one of the clinically important histopathological features in HNSCC. The purpose of this study was to analyze possible associations between ¹⁸F-FDG-PET findings and MVD parameters in HNSCC. Materials and Methods: Overall, 22 patients with a mean age of 55.2 ± 11.0 and with different HNSCC were acquired. In all cases, whole-body ¹⁸F-FDG-PET was performed. For each tumor, the maximum and mean standardized uptake values (SUV_max; SUV_mean) were determined. The MVD, including stained vessel area and total number of vessels, was estimated on CD105 stained specimens. All specimens were digitalized and analyzed by using ImageJ software 1.48v. Spearman's correlation coefficient (r) was used to analyze associations between investigated parameters. p-values of <0.05 were taken to indicate statistical significance. Results: SUV_max correlated with vessel area (r = 0.532, p = 0.011) and vessel count (r = 0.434, p = 0.043). Receiver operating characteristic analysis identified a threshold SUV_max of 15 to predict tumors with high MVD with a sensitivity of 72.7% and specificity of 81.8%, with an area under the curve of 82.6%. Conclusion: ⁸F-FDG-PET parameters correlate statistically significantly with MVD in HNSCC. SUV_max may be used for discrimination of tumors with high tumor-related MVD.

Can the Efficacy of [18F]FDG-PET/CT in Clinical Oncology Be Enhanced by Screening Biomolecular Profiles?

Positron Emission Tomography (PET) is a functional imaging modality widely used in clinical oncology. Over the years the sensitivity and specificity of PET has improved with the advent of specific radiotracers, increased technical accuracy of PET scanners and incremental experience of Radiologists. However, significant limitations exist—most notably false positives and false negatives. Additionally, the accuracy of PET varies between cancer types and in some cancers, is no longer considered a standard imaging modality. This review considers the relative influence of macroscopic tumour features such as size and morphology on 2-Deoxy-2-[¹⁸F]fluoroglucose ([¹⁸F]FDG) uptake by tumours which, though well described in the literature, lacks a comprehensive assessment of biomolecular features which may influence [¹⁸F]FDG uptake. The review aims to discuss the potential influence of individual molecular markers of glucose transport, glycolysis, hypoxia and angiogenesis in addition to the relationships between these key cellular processes and their influence on [¹⁸F]FDG uptake. Finally, the potential role for biomolecular profiling of individual tumours to predict positivity on PET imaging is discussed to enhance accuracy and clinical utility.

Positron Emission Tomography 18F-Fluorodeoxyglucose Uptake Correlates with KRAS and EMT Gene Signatures in Operable Esophageal Adenocarcinoma

BACKGROUND

18F-fluorodeoxyglucose positron emission tomography is an imaging modality critical to the diagnosis and staging of esophageal cancer. Despite this, the genetic abnormalities associated with increased 18F-fluorodeoxyglucose (FDG)-maximum standardized uptake value (SUVmax) have not been previously explored in esophageal adenocarcinoma.

MATERIALS AND METHODS

Treatment-naïve patients, for whom frozen tissue and 18F-fluorodeoxyglucose positron emission tomography data were available, undergoing esophagectomy from 2003 to 2012, were identified. Primary tumor FDG-uptake (SUVmax) was quantified as low (<5), moderate, or high (>10). Genome-wide expression analyses (e.g., microarray) were used to examine gene expression differences associated with FDG-uptake.

RESULTS

Eighteen patients with stored positron emission tomography data and tissue were reviewed. Overall survival was similar between patients with high (n = 9) and low (n = 6) FDG-uptake tumors (P = 0.71). Differences in gene expression between tumors with high and low FDG-uptake included enriched expression of various matrix metalloproteinases, extracellular-matrix components, oncogenic signaling members, and PD-L1 (fold-change>2.0, P < 0.05) among the high-FDG tumors. Glycolytic gene expression and pathway involvement were similar between the high- and low-FDG tumor subsets (P = 0.126). Gene ontology analysis of the most differentially expressed genes demonstrated significant upregulation of gene sets associated with extracellular matrix organization and vascular development (P < 0.005). Gene set enrichment analysis further demonstrated associations between FDG-uptake intensity and canonical oncogenic processes, including hypoxia, angiogenesis, KRAS signaling, and epithelial-to-mesenchymal transition (P < 0.001). Interestingly, KRAS expression did not predict worse survival in a larger cohort (n = 104) of esophageal adenocarcinomas (P = 0.64).

CONCLUSIONS

These results suggest that elevated FDG-uptake is associated with a variety of oncogenic alterations in operable esophageal adenocarcinoma. These pathways present potential therapeutic targets among tumors exhibiting high FDG-uptake.

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.

Molecular biological correlation of fluorine-18 fluorodeoxyglucose uptake in esophageal squamous cell carcinoma

OBJECTIVE

The aim of this study was to assess the relationship between fluorine-18 fluorodeoxyglucose (F-FDG) uptake and molecular biological markers in esophageal squamous cell carcinoma (ESCC) patients.

METHODS

Our patient population included 51 patients who underwent F-FDG PET/computed tomography before surgery. Excised tumor tissue was analyzed immunohistochemically using monoclonal antibodies for glucose transporter-1 (GLUT-1), GLUT-3, CD34 [microvessel density (MVD) marker], CD68 (macrophage marker), and CD163 (tumor-associated macrophage marker). The relationships among pathological factors [pathological T stage (p-T stage), pathological lymph node status (p-N status), pathological stage (p-stage), and pathological tumor length], the maximum standardized uptake value (SUVmax), and these molecular biological markers were evaluated using Spearman's rank test and the Kruskal-Wallis test.

RESULTS

GLUT-1, GLUT-3, CD34, and CD163 significantly correlated with SUVmax (r=0.547, P<0.001 for GLUT-1; r=0.569, P<0.001 for GLUT-3; r=0.463, P=0.001 for CD34, r=0.455, P=0.001 for CD163), whereas SUVmax, GLUT-1, GLUT-3, CD34, and CD163 significantly correlated with p-T stage (r=0.552, P<0.001 for SUVmax, r=0.307, P=0.03 for GLUT-1, r=0.349, P=0.013 for GLUT-3, r=0.313, P=0.027 for CD34, r=0.526 for CD163, P<0.001), but not with p-N status. CD68 levels showed no significant correlation with SUVmax, p-T stage, p-stage, or p-N status.

CONCLUSION

SUVmax, GLUT-1 expression, GLUT-3 expression, MVD, and TAMs show a relationship with the tumor stage and extent of ESCC. GLUT-1, GLUT-3, MVD, and TAMs are associated with the mechanism of F-FDG uptake in ESCC.

Association Between (18)F-FDG Avidity and the BRAF Mutation in Papillary Thyroid Carcinoma

PURPOSE

The BRAF mutation, a potential prognostic factor in papillary thyroid carcinoma (PTC), is associated with a high expression of the glucose transporter gene. We investigated which clinicopathologic factors, including BRAF mutation status, influence (18)F-fluoro-2-deoxyglucose ((18)F-FDG) avidity.

METHODS

We retrospectively reviewed 55 patients who underwent BRAF analysis from biopsy-confirmed PTC and (18)F-FDG positron emission tomography/computed tomography within 6 months before undergoing thyroid surgery from September 2008 to August 2014. Tumors were considered to be (18)F-FDG avid if the uptake was greater than that of the liver. (18)F-FDG uptake of PTCs was also analyzed semiquantitatively using SUVmax. The association between (18)F-FDG avidity and clinicopathologic variables (age, tumor size, perithyroidal extension, cervical lymph node status, and BRAF mutation status) was investigated.

RESULTS

Twenty-nine (52.7 %) of 55 patients had (18)F-FDG-avid PTCs. PTCs with the BRAF mutation showed higher (18)F-FDG avidity (24/38, 63.2 %) than those without (5/17, 29.4 %). The BRAF mutation (p = 0.025) and tumor size (p = 0.003) were significantly associated with (18)F-FDG avidity in univariate analysis, and the BRAF mutation status remained significant after adjusting for tumor size in multivariate analysis (p = 0.015). In the subgroup of tumor size ≥ 1 cm, the BRAF mutation was the only factor significantly associated with (18)F-FDG avidity (p = 0.021). The mean SUVmax of PTCs with the BRAF mutation was significantly higher than that of those without (4.89 ± 6.12 vs. 1.96 ± 1.10, p = 0.039).

CONCLUSIONS

The BRAF mutation must be one of the most important factors influencing (18)F-FDG avidity in PTCs, especially in those with a tumor size ≥ 1 cm.

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.

Correlation between the Uptake of 18F-Fluorodeoxyglucose (18F-FDG) and the Expression of Proliferation-Associated Antigen Ki-67 in Cancer Patients: A Meta-Analysis

Objective

To study the correlation between ¹⁸F-FDG uptake and cell proliferation in cancer patients by meta-analysis of published articles.

Methods

We searched PubMed (MEDLINE included), EMBASE, and Cochrane Database of Systematic Review, and selected research articles on the relationship between ¹⁸F-FDG uptake and Ki-67 expression (published between August 1, 1994-August 1, 2014), according to the literature inclusion and exclusion criteria. The publishing language was limited to English. The quality of included articles was evaluated according to the Quality Assessment of Diagnosis Accuracy Studies-2 (QUADAS-2). The correlation coefficient (r) was extracted from the included articles and processed by Fisher's r-to-z transformation. The combined correlation coefficient (r) and the 95% confidence interval (CI) were calculated with STATA 11.0 software under a random-effects model. Begg's test was used to analyze the existence of publication bias and draw funnel plot, and the sources of heterogeneity were explored by sensitivity and subgroup analyses.

Results

According to the inclusion and exclusion criteria, 79 articles were finally included, including 81 studies involving a total of 3242 patients. All the studies had a combined r of 0.44 (95% CI, 0.41-0.46), but with a significant heterogeneity (I² = 80.9%, P<0.01). Subgroup analysis for different tumor types indicated that most subgroups showed a reduced heterogeneity. Malignant melanoma (n = 1) had the minimum correlation coefficient (-0.22) between ¹⁸F-FDG uptake and Ki-67 expression, while the thymic epithelial tumors (TETs; n = 2) showed the maximum correlation coefficient of 0.81. The analytical results confirmed that correlation between ¹⁸F-FDG uptake and Ki-67 expression was extremely significant in TETs, significant in gastrointestinal stromal tumors (GISTs), moderate in patients with lung, breast, bone and soft tissue, pancreatic, oral, thoracic, and uterine and ovarian cancers, average in brain, esophageal and colorectal cancers, and poor in head and neck, thyroid, gastric and malignant melanoma tumors. Subgroup analysis indicated that positron emission tomography (PET) or PET/CT imaging technology or Ki-67 and standardized uptake value (SUV) measurement technology did not significantly affect the results of r values, and Begg's test showed no significant publication bias.

Conclusion

In cancer patients, ¹⁸F-FDG uptake showed a moderate positive correlation with tumor cell proliferation. Different tumor types exhibited varied degree of correlation, and the correlation was significant in TETs and GSTs. However, our results need further validation by clinical trials with a large sample of different tumor types.

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.

Hypoxia, blood flow and metabolism in squamous-cell carcinoma of the head and neck: correlations between multiple immunohistochemical parameters and PET

Background

The relationship between the uptake of [¹⁸F]fluoroerythronitroimidazole ([¹⁸F]FETNIM), blood flow ([¹⁵O]H₂O) and 2-[¹⁸F]fluoro-2-deoxyglucose ([¹⁸F]FDG) and immunohistochemically determined biomarkers was evaluated in squamous-cell carcinomas of the head and neck (HNSCC).

Methods

[¹⁸F]FETNIM and [¹⁸F]FDG PET were performed on separate days on 15 untreated patients with HNSCC. Hypoxia imaging with [¹⁸F]FETNIM was coupled with measurement of tumor blood flow using [¹⁵O]H₂O. Uptake of [¹⁸F]FETNIM was measured as tumor-to-plasma ratio (T/P) and fractional hypoxic volume (FHV), and that of [¹⁸F]FDG as standardized uptake value (SUV) and the metabolically active tumor volume (TV). Tumor biopsies were cut and stained for GLUT-1, Ki-67, p53, CD68, HIF-1α, VEGF_sc-152, CD31 and apoptosis. The expression of biomarkers was correlated to PET findings and patient outcome.

Results

None of the PET parameters depicting hypoxia and metabolism correlated with the expression of the biomarkers on a continuous scale. When PET parameters were divided into two groups according to median values, a significant association was detected between [¹⁸F]FDG SUV and p53 expression (p =0.029) using median SUV as the cut-off. There was a significant association between tumor volume and the amount of apoptotic cells (p =0.029). The intensity of VEGF stained cells was associated with [¹⁸F]FDG SUV (p =0.036). Patient outcome was associated with tumor macrophage content (p =0.050), but not with the other biomarkers. HIF-1α correlated with GLUT-1 (r_s =0.553, p =0.040) and Ki-67 with HIF-1α (r_s =506, p =0.065). p53 correlated inversely with GLUT-1 (r_s = −618, p =0.019) and apoptosis with Ki-67 (r_s = −638, p =0.014).

Conclusions

A high uptake of [¹⁸F]FDG expressed as SUV is linked to an aggressive HNSCC phenotype: the rate of apoptosis is low and the expressions of p53 and VEGF are high. None of the studied biomarkers correlated with perfusion and hypoxia as evaluated with [¹⁵O]H₂O-PET and [¹⁸F]FETNIM-PET. Increased tumor metabolism evaluated with PET may thus signify an aggressive phenotype, which should be taken into account in the management of HNSCC.

Pre-treatment metabolic tumor volume and total lesion glycolysis are useful prognostic factors for esophageal squamous cell cancer patients

OBJECTIVES

To study application of the maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV) and total lesion glycolysis (TLG) with 18F-FDG PET/CT for predicting prognosis of esophageal squamous cell cancer (ESC) patients.

METHODS

Eighty-six patients with ESC staged from I to IV were prospectively enrolled. Cisplatin-based chemoradiotherapy (CCRT) or palliative chemoradiotherapy were the main treatment methods and none received surgery. 18F-FDG PET/CT scans were performed before the treatment. SUVmax, MTV, and TLG were measured for the primary esophageal lesion and regional lymph nodes. Receiver operating characteristic curves (ROCs) were generated to calculate the P value of the predictive ability and the optimal threshold.

RESULTS

MTV and TLG proved to be good indexes in the prediction of outcome for the ESC patients. An MTV value of 15.6 ml and a TLG value of 183.5 were optimal threshold to predict the overall survival (OS). The areas under the curve (AUC) for MTV and TLG were 0.74 and 0.70, respectively. Kaplan-Meier analysis showed an MTV less than 15.6 ml and a TLG less than 183.5 to indicate good media survival time (p value <0.05). In the stage III-IV patient group, MTV could better predict the OS (P < 0.001), with a sensitivity and specificity of 0.80 and 0.67, respectively.

CONCLUSIONS

Pre-treatment MTV and TLG are useful prognostic factors in non- surgical ESC.

Prognostic value of baseline FDG uptake on PET-CT in esophageal carcinoma

AIM: To evaluate the influence of baseline maximum standardized uptake value (SUV_max) on survival in a cohort of patients, undergoing positron emission tomography-computed tomography (PET-CT) scan for esophageal carcinoma.

METHODS: The pre-treatment SUV_max numeric reading was determined in patients with confirmed esophageal or junctional cancer having PET-CT scan during the time period 1^st January 2007 until 31^st July 2012. A minimum follow up of 12 mo was required. Patients were subdivided into quartiles according to SUV_max value and the influence of SUV_max on survival was assessed using univariate and multivariate analysis. The following pre-treatment factors were investigated: patient characteristics, tumor characteristics and planned treatment.

RESULTS: The study population was 271 patients (191 male) with esophageal or junctional carcinoma. The median age was 65 years (range 40-85) and histologic subtype was adenocarcinoma in 197 patients and squamous carcinoma in 74 patients. The treatment intent was radical in 182 and palliative in 89 patients. SUV_max was linked to histologic subtype (P = 0.008), tumor site (P = 0.01) and Union for International Cancer Control (UICC) stage (P < 0.001). On univariate analysis, prognosis was significantly associated with SUV_max (P = 0.001), T-stage (P < 0.001) and UICC stage (P < 0.001). On multivariate analysis, only T-stage and UICC stage remained significant.

CONCLUSION: Pretreatment SUV_max was not a useful marker in isolation for determining prognosis of patients with esophageal carcinoma.

Non-FDG-avid primary papillary thyroid carcinoma may not differ from FDG-avid papillary thyroid carcinoma

BACKGROUND

FDG (2-[(18)F]Fluoro-2-D-deoxyglucose-positron emission tomography (PET)/computed tomography (CT), which can detect a change in glucose metabolism in cancer cells, has been introduced as a diagnostic and prognostic tool in papillary thyroid carcinoma (PTC). However, differences in the clinicopathological and biological characteristics between primary PTCs with FDG uptake and those without FDG uptake are not well established.

METHODS

A total of 188 patients with PTC who had preoperative PET/CT scans were enrolled to compare the differences of clinicopathological parameters between FDG-avid (F-PTC; n = 150) and non-FDG-avid tumors (FN-PTC; n = 38). Immunohistochemical staining for glucose transporter (GLUT)-1 and hypoxia-inducible factor-1 alpha (HIF-1α) was performed.

RESULTS

FN-PTCs were smaller; had a lower incidence of lymphatic invasion, vascular invasion, multifocality, and central lymph node metastasis; and had a lower maximum standardized uptake value than F-PTCs. After exclusion of high-risk patients for recurrence, FN-PTCs remained smaller (p < 0.001) and had less lymphatic invasion (p = 0.061). Among tumors larger than the spatial resolution of the PET/CT scan, macrocalcification was more frequent in FN-PTC than in F-PTC (p = 0.043). While FN-PTC and F-PTC showed no difference in GLUT-1 expression (50% vs. 75%, p = 0.363), FN-PTC showed lower HIF-1α immunoreactivity than F-PTC (25.0% vs. 75.0%, p = 0.032).

CONCLUSION

Tumor size and macrocalcification are clinicopathological differences between FN-PTC and F-PTC. Biologically, HIF-1α may be responsible for increased FDG uptake in PTC.

Metabolic symbiosis in cancer: refocusing the Warburg lens

Using relatively primitive tools in the 1920s, Otto Warburg demonstrated that tumor cells show an increased dependence on glycolysis to meet their energy needs, regardless of whether they were well-oxygenated or not. High rates of glucose uptake, fueling glycolysis, are now used clinically to identify cancer cells. However, the Warburg effect does not account for the metabolic diversity that has been observed amongst cancer cells nor the influences that might direct such diversity. Modern tools have shown that the oncogenes, variable hypoxia levels, and the utilization of different carbon sources affect tumor evolution. These influences may produce metabolic symbiosis, in which lactate from a hypoxic, glycolytic tumor cell population fuels ATP production in the oxygenated region of a tumor. Lactate, once considered a waste product of glycolysis, is an important metabolite for oxidative phosphorylation in many tissues. While much is known about how muscle and the brain use lactate in oxidative phosphorylation, the contribution of lactate in tumor bioenergetics is less defined. A refocused perspective of cancer metabolism that recognizes metabolic diversity within a tumor offers novel therapeutic targets by which cancer cells may be starved from their fuel sources, and thereby become more sensitive to traditional cancer treatments.

Genotyping analysis and ¹⁸FDG uptake in breast cancer patients: a preliminary research

Background

Diagnostic imaging plays a relevant role in the care of patients with breast cancer (BC). Positron Emission Tomography (PET) with 18F-fluoro-2-deoxy-D-glucose (FDG) has been widely proven to be a clinical tool suitable for BC detection and staging in which the glucose analog supplies metabolic information about the tumor. A limited number of studies, sometimes controversial, describe possible associations between FDG uptake and single nucleotide polymorphisms (SNPs). For this reason this field has to be explored and clarified. We investigated the association of SNPs in GLUT1, HIF-1a, EPAS1, APEX1, VEGFA and MTHFR genes with the FDG uptake in BC.

Methods

In 26 caucasian individuals with primary BC, whole-body PET-CT scans were obtained and quantitative analysis was performed by calculating the maximum Standardized Uptake Value normalized to body-weight (SUVmax) and the mean SUV normalized to body-weight corrected for partial volume effect (SUVpvc). Human Gene Mutation Database and dbSNP Short Genetic Variations database were used to analyze gene regions containing the selected SNPs. Patient genotypes were obtained using Sanger DNA sequencing analysis performed by Capillary Electrophoresis.

Results

BC patients were genotyped for the following nine SNPs: GLUT1: rs841853 and rs710218; HIF-1a: rs11549465 and rs11549467; EPAS1: rs137853037 and rs137853036; APEX1: rs1130409; VEGFA: rs3025039 and MTHFR: rs1801133. In this work correlations between the nine potentially useful polymorphisms selected and previously suggested with tracer uptake (using both SUVmax and SUVpvc) were not found.

Conclusions

The possible functional influence of specific SNPs on FDG uptake needs further studies in human cancer. In summary, this is the first pilot study, to our knowledge, which investigates the association between a large panel of SNPs and FDG uptake specifically in BC patients. This work represents a multidisciplinary and translational medicine approach to study BC where, the possible correlation between SNPs and tracer uptake, may be considered to improve personalized cancer treatment and care.

Confirmation of histology of PET positive lymph nodes recovered by hand-video-assisted thoracoscopy surgery

PET/CT (Positron Emission Tomography-Computed Tomography) is an advanced diagnostic imaging device that combines both PET and an X-ray CT. This study evaluates the effects of PET/CT on detecting primary tumors and metastases, and looks at the therapeutic effect of minimally invasive surgery on esophageal cancer patients. Eighty patients with esophageal cancer were enrolled in the study between January, 2004 and December, 2007, who were randomly divided into two groups of 40, one of which was treated with hand-video-assisted thoracoscopy surgery (HVATS) esophagectomy and one of which was treated with conventional surgery. All patients underwent a PET/CT scan 2-3 weeks before their operation, and their cervical, thoracic and upper abdominal lymph nodes were biopsied. All the primary esophageal lesions showed high FDG uptake. The maximum standardized uptake value (SUV) was 3.78-25.64 (11.73±5.32), while the mean SUV was 3.65=16.92 (9.12±4.37). Using 2.5 as the SUV standard, all esophageal lesions were detected by PET/CT image. Of the 80 patients, 53 had lymph nodal metastases, with a total of 142 metastatic lymph nodes, which showed high FDG uptake. The maximum SUV was 2.77-14.63 (7.98±3.25), and the mean SUV was 2.31-12.84 (5.34±3.19). The visual analysis from the PET/CT scan showed a sensitivity of 86.62%, a specificity of 95.85%, a positive predictive value of 93.89%, a negative predictive value of 90.69% and an accuracy of 91.94%. The PET/CT scan showed a high sensitivity and specificity in detecting primary esophageal cancer and lymph nodal metastases. The mean post-surgery life expectancies for patients undergoing HVATS and conventional surgery are 27.93 months and 28.05 months, respectively. The two groups showed no statistically significant difference. We thus conclude that PET/CT combined with HVATS is a new choice for esophageal carcinoma patients.

The relationship between GLUT-1 and vascular endothelial growth factor expression and 18F-FDG uptake in esophageal squamous cell cancer patients

PURPOSE

To examine the relationship between glucose transporter-1 (GLUT-1) and vascular endothelial growth factor (VEGF) expression and (18)F-FDG uptake in esophageal squamous cell cancer patients.

MATERIALS AND METHODS

Fifty-seven patients (52 male and 5 female) were included in this study. (18)F-FDG PET/CT was performed prior to the surgery. Immunohistochemistry was performed using postoperative histopathological specimens. The estimation of immunohistochemistry was conducted using scoring analysis. We investigated the correlations between maximum standardized uptake value (SUV(max)) and GLUT-1/VEGF expressions/pathologic tumor length (p-tumor length), and the relationships between pathologic T (p-T) stage and GLUT-1/VEGF expressions/SUV(max) and between lymph node metastasis (p-N) stage and GLUT-1/VEGF expressions/SUV(max).

RESULTS

SUV(max) significantly correlated with GLUT-1 expressions and p-tumor length (GLUT-1: r = 0.475, P < 0.001; p-tumor length: r = 0.475, P < 0.001). SUV(max) of the primary tumor had a significant relationship with p-T stage, p-N stage, and VEGF expression (p-T stage: P < 0.001; p-N stage: P = 0.037; VEGF expression: P = 0.009). There was a statistically significant difference between GLUT-1 expression and p-T stage/VEGF expression, but not p-N stage (p-T stage: P = 0.012; VEGF expression: P = 0.01; p-N stage: P = 0.572). VEGF expression had a significant relationship with p-T stage, but not with p-N stage (p-T stage: P = 0.032; p-N stage: P = 0.763).

CONCLUSION

(18)F-FDG uptake can be determined by GLUT-1 and VEGF. SUV(max) would have a connection with the tumor progression and lymph node metastasis.

Imaging primary prostate cancer with 11C-Choline PET/CT: relation to tumour stage, Gleason score and biomarkers of biologic aggressiveness

Background

As a significant overlap of 11C-Choline standardized uptake value (SUV) between prostate cancer and benign prostate hyperplasia (BPH) tissue, controversy exists regarding the clinical value of 11C-Choline PET/CT scan in primary prostate cancer. In this study, the SUVmax of the prostate lesions and the pelvic muscles were measured and their ratios (SUVmax-P/M ratio) were calculated. Then we evaluated whether the tracer 11C-Choline uptake, quantified as SUVmax-P/M ratio, correlated with tumour stage, Gleason score, and expression levels of several biomarkers of aggressiveness.

Methods

Twenty-six patients with primary prostate cancer underwent 11C-Choline PET/CT. Tumour specimens from these patients were graded histopathologically, and immunnohistochemistry for Ki-67, CD31, androgen receptor (AR), Her-2/neu, Bcl-2, and PTEN were performed.

Results

Both SUVmax and SUVmax-P/M ratio showed no significant difference between patients with tumour stage II and III, but significantly elevated in patients with tumour stage IV. SUVmax-P/M ratio was also significantly higher in lesions with Gleason score of 4+3 or higher versus less than or equal to 3+4. SUVmax-P/M ratio was found significantly correlated with expression levels of Ki-67 and CD31. In addition, a higher SUVmax-P/M ratio was demonstrated in Her-2/neu positive subgroup than negative subgroup. At the same time, Gleason score and expression levels of these biomarkers showed no significant association with SUVmax.

Conclusions

Using the parameter SUVmax-P/M ratio, 11C-Choline PET/CT may be a valuable non-invasive imaging technology in the diagnosis of primary prostate cancer.

Accuracy of PET-CT in predicting survival in patients with esophageal cancer

BACKGROUND

Positron emission tomography (PET) is an integral part of tumor staging for patients with esophageal cancer. Recent studies suggest a role for PET scan in predicting survival in these patients, but this relationship is unclear in the setting of neoadjuvant therapy. We examined pretreatment maximum standard uptake value (SUV(max)) of the primary tumor in patients treated with and without neoadjuvant therapy.

METHODS

All patients undergoing esophagectomy with a preoperative PET scan over a nine-year period (2001-2010) were identified from a prospectively maintained database. Positron emission tomography data were obtained from computers housing the original PET scans. Overall survival was correlated with SUV(max) of the primary tumor.

RESULTS

A total of 191 patients were identified, and 103 patients met inclusion criteria. Eighty-two had an adenocarcinoma (80%), and 21 (20%) had a squamous cell carcinoma. Fifty-seven (55%) patients received neoadjuvant therapy. In the surgery alone group, a SUV(max) of > 5.0 in the primary tumor was associated with poor prognosis [Hazard Ratio (HR) 0.32; p = 0.007], but this factor did not retain its significance on multivariate analysis (HR 0.65; p = 0.43). Pretreatment SUV(max) in patients who underwent neoadjuvant therapy was not significant in predicting overall survival (p = 0.10).

CONCLUSIONS

This study does not support the use of SUV(max) on pretreatment PET scans as a prognostic tool for patients with esophageal cancer, especially in those who have received neoadjuvant therapy. Lymph node status is a more accurate predictor of outcome, and efforts to improve pretreatment staging should focus on this factor.

Molecular mechanism underlying the detection of colorectal cancer by 18F-2-fluoro-2-deoxy-D-glucose positron emission tomography

BACKGROUND

Biological imaging by positron emission tomography (PET) using 18F-2-fluoro-2-deoxy-D-glucose (FDG) has been widely used clinically for the detection of primary tumors and for early prediction of response to chemotherapy. In this study, we examined the molecular mechanism underlying the detection of colorectal cancers by FDG-PET.

MATERIAL AND METHODS

In all, 37 patients with colorectal cancer were examined with FDG-PET, and the maximal standardized uptake value (SUV) was calculated. Using surgical tissue samples, we examined the expression levels of hypoxia-inducible factor alpha (HIF1α), a marker of tissue hypoxia; proliferative cellular nuclear antigen (PCNA), a marker of proliferation; and glucose transporter (GLUT)1 and hexokinase (HK)2, protein of glucose uptake by using reverse transcriptase-polymerase chain reaction.

RESULTS

All except two colorectal cancer lesions showed increased uptake of FDG. The mean SUV of FDG-PET was 12.0 ± 1.2 (±SEM). The mean mRNA expression levels of GLUT1 and HK2 were significantly higher in cancer tissues than in the surrounding normal mucosa. Moreover, to promote the upregulation of glucose uptake, the expressions of HIF1α and PCNA were induced to 2.6 and 3.3 times higher than that in the normal mucosa. However, the quantitative correlation analysis showed SUV was correlated with HIF1α expression but not with PCNA expression.

CONCLUSION

Our molecular-based analysis suggested that FDG accumulation due to induction of glucose uptake proteins might be associated with the hypoxic environment in tumors rather than the tumor growth. Therefore, for assessing the efficacy of chemotherapy using FDG-PET, we must keep in mind that SUV does not indicate the tumor growth directly.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Early FDG PET at 10 or 20 Gy under chemoradiotherapy is prognostic for locoregional control and overall survival in patients with head and neck cancer

PURPOSE

Our study aimed to explore the optimal timing as well as the most appropriate prognostic parameter of (18)F-fluorodeoxyglucose positron emission tomography (FDG PET) during chemoradiotherapy (CRT) for an early prediction of outcome for patients with head and neck squamous cell carcinoma (HNSCC).

METHODS

Serial PET data (before and three times during CRT) of 37 patients with advanced stage HNSCC, receiving combined CRT between 2005 and 2009, were evaluated. The maximum standardized uptake value (SUV(max)), the average SUV (SUV(mean)) and the gross tumour volume determined by FDG PET (GTV PET), based on a source to background algorithm, were analysed. Stratified actuarial analysis was performed for overall survival (OS), disease-free survival (DFS) and locoregional control (LRC). The median follow-up time was 26 months (range 8-50).

RESULTS

For all patients, OS was 51%, DFS 44% and LRC 55% after 2 years. The 2-year OS (88%) and 2-year LRC (88%) were higher for patients whose SUV(max) of the primary tumour decreased 50% or more from the beginning (0 Gy) to week 1 or 2 (10 or 20 Gy) of CRT (ΔSUV(max10/20) ≥ 50%) than for patients with ΔSUV(max20) < 50% (2-year OS = 38%; p = 0.02; 2-year LRC 40%; p = 0.06). A pretreatment GTV PET below the median of 10.2 ml predicted a better 2-year OS (34% for GTV PET ≥ 10.2 ml vs 83% for GTV PET < 10.2 ml; p = 0.02).

CONCLUSION

The decrease of SUV(max) from before (0 Gy) to week 1 or 2 (10 or 20 Gy) of CRT is a potential prognostic marker for patients with HNSCC. Because GTV PET depends on the applied method of analysis, we suggest the use of SUV(max), especially ΔSUV(max10/20), for an early estimation of therapy outcome. Confirmatory studies are warranted.

PET and PET-CT in esophageal and gastric cancer

Esophageal cancer ranks among the ten most common malignancies in the world and is a frequent cause of cancer-related death. Almost all therapeutic modalities for esophageal cancer are associated with considerable mortality and morbidity. Consequently, there has been growing concern regarding effective management of esophageal cancer. Imaging plays an important role in the initial selection of patients. 18F-fluorodeoxyglucose positron emission tomography (18F-FDG-PET) is playing an increasing role in the management of esophageal cancer. The role of FDG-PET in diagnosis, preoperative staging, monitoring of response to neoadjuvant therapy, and detection of disease recurrence is evaluated in this chapter.

Clinical significance of GLUT-1 expression in patients with esophageal cancer treated with concurrent chemoradiotherapy

This study aimed to investigate whether glucose transporter-1 (GLUT-1) expression in a pretreatment esophageal cancer biopsy was predictive of clinical outcomes in patients with esophageal cancer undergoing concurrent chemoradiotherapy (CRT). A total of 25 patients with esophageal cancer treated with concurrent CRT were reviewed. Radiotherapy was administered up to total doses of 40-66.6 Gy (median 66.6 Gy) with a single fraction of 1.8-2 Gy. Regarding chemotherapy, cisplatin (80 mg/m(2) on day 1) and 5-fluorouracil (800 mg/m(2) on days 2-6) were used concurrently with radiotherapy, every 3-4 weeks for a total of 1-2 courses. Tissue samples from esophageal carcinoma were obtained from the 25 patients by biopsy prior to concurrent CRT, and a semiquantitative analysis of GLUT-1 expression was performed using immunohistochemical staining. High GLUT-1 expression was observed in 7 of 25 (28%) patients, and GLUT-1 expression was significantly correlated with clinical T stage (p=0.0454), clinical N stage (p=0.0324) and initial response to CRT (p=0.0185). Patients with a high GLUT-1 expression had significantly poorer local control (LC) (5-year LC 28.6%) than those with a low expression (5-year LC 73.4%, p<005). Multivariate analysis revealed that GLUT-1 and the number of chemotherapy courses were independent prognostic factors for LC. Patients with a high GLUT-1 expression had significantly lower recurrence-free survival (RFS) compared to those with a low GLUT-1 expression (p=0.0405). Multivariate analysis revealed that GLUT-1, the number of chemotherapy courses and clinical M stage were independent prognostic factors for RFS. GLUT-1 expression was significantly correlated with clinical T stage, clinical N stage and initial response to concurrent CRT, and was predictive of LC and RFS for patients with esophageal cancer treated with concurrent CRT.

The XbaI G>T polymorphism of the glucose transporter 1 gene modulates 18F-FDG uptake and tumor aggressiveness in breast cancer

We investigated the relevance of single-nucleotide polymorphisms (SNPs) in the glucose transporter 1 (GLUT1) gene to the uptake of (18)F-FDG and tumor aggressiveness in breast cancer.

METHODS

In 52 individuals with breast cancer, a diagnostic PET/CT scan was obtained, and the standardized uptake value was determined as a measure of (18)F-FDG uptake using a region-of-interest technique. Three GLUT1 SNPs (XbaI G>T, HpyCH4V A>T, and HaeIII T>C) were investigated in genomic DNA that was isolated from the paraffin-embedded specimens of all patients. Tumors were typed and graded according to the World Health Organization classifications.

RESULTS

The GG genotype of the XbaI G>T SNP was associated with increased tumor uptake of (18)F-FDG, with a mean standardized uptake value of 11.7 (TT/GT genotypes, 5.9; P = 0.03). Furthermore, the GG genotype was positively related to enhanced tumor proliferation (mitotic count, P = 0.01). In line with this finding, the GG genotype was absent in grade 1 carcinomas and increasingly prevalent in tumors with higher malignancy (grade 2, 28.0%; grade 3, 50%; P = 0.04).

CONCLUSION

This study found that the XbaI G>T SNP of the GLUT1 gene is associated with an increased (18)F-FDG uptake and a more advanced tumor grade or growth in breast cancer. Thus, this genetic variant might favor aggressive phenotypes by modulating the efficiency of cancer cells to recruit glucose and escalate growth rate, suggesting the XbaI G>T SNP as a proliferation-related prognostic factor.

Does the value of PET-CT extend beyond pretreatment staging? An analysis of survival in surgical patients with esophageal cancer

BACKGROUND

Studies of positron emission tomography (PET) have focused mainly on tumor staging. The role of PET in predicting survival has received less attention. We sought to assess the relationship of pretreatment maximum standard uptake value (SUV(max)) to survival in surgical patients with esophageal cancer.

METHODS

The study consisted of 72 esophagectomy patients (60 with adenocarcinoma) undergoing resection between July 2005 and April 2009. PET combined with computed tomography (PET-CT) was performed at a single center, and SUV(max) was recorded prior to any therapy. Survival was assessed at a median follow-up of 19 months.

RESULTS

The median SUV(max) was 6.25. A receiver operating characteristic curve identified SUV(max) 4.5 to optimally discriminate survival. Patients with low SUV(max) (<4.5) had significantly (p = 0.0003) better survival than those with high SUV(max) (>or=4.5). Stage 3 patients with low SUV(max) had significantly better survival (p = 0.0069) than those with high SUV(max). Likewise, N1 disease patients with low SUV(max) had significantly better survival (p = 0.008) than those with high SUV(max). Multivariate analysis identified SUV(max) to be an independent predictor of survival (p = 0.0021).

CONCLUSION

Pretreatment PET-CT SUV(max) independently predicts survival in patients with esophageal carcinoma undergoing resection. SUV(max) may be a valuable marker of tumor biology that could potentially be exploited for prognostic and therapeutic purposes.

Predictive value of initial PET-SUVmax in patients with locally advanced esophageal and gastroesophageal junction adenocarcinoma

INTRODUCTION

We have previously shown that in early clinical stage esophageal adenocarcinoma, a positron emission tomography standardized uptake values (PET SUVmax) of <4.5 is associated with earlier pathologic stage and predicts better survival. In this study, we analyze the impact of the pretreatment PET SUVmax in patients with locally advanced esophageal adenocarcinoma who undergo preoperative chemoradiotherapy.

METHODS

We performed a retrospective analysis, selecting patients with adenocarcinoma of the esophagus who had a pretreatment PET scan and who received chemoradiotherapy before esophagectomy. Data recorded included demographics, PET SUVmax, treatment details, pathologic details, and survival data. Comparison of categorical variables was done by chi analysis, continuous variables by t test, survival analysis by the Kaplan-Meier method, and comparisons of survival using the log-rank test.

RESULTS

Between January 1996 and September 2007, 189 patients were appropriate for this analysis. The initial PET SUVmax was <4.5 in 28 patients and >or=4.5 in 161 patients. The two groups were similar with regards to demographics and treatment details. Patients in the low SUV group were less likely to show evidence of treatment response after chemoradiotherapy, including a higher likelihood of residual nodal disease and a lower likelihood of a pathologic complete response and estimated treatment response. However, both groups had similar survival.

CONCLUSIONS

Although the initial PET SUVmax does not predict survival in patients with locally advanced esophageal adenocarcinoma who receive preoperative chemoradiotherapy, patients with a high initial SUVmax respond better to preoperative therapy. These results can be used to better select esophageal cancer patients for combined modality treatment.

Prognostic significance of SUV on PET/CT in patients with esophageal cancer: a systematic review and meta-analysis

BACKGROUND AND PURPOSE

Esophageal cancer is the third most common gastrointestinal malignancy with a poor long-term survival and high mortality. Surgical resection provides the only chance of cure. The tumor-node metastasis stage classification system is a strong prognostic parameter predicting the prognosis. We performed the present meta-analysis to comprehensively review the evidence for use of standardized uptake value (SUV) measured on tumor to predict prognosis of esophageal cancer.

METHODS

We searched for articles published in English or Chinese; limited to esophageal cancer; F-fluoro-2-deoxy-glucose (F-FDG) uptake on positron emission tomography (PET) performed on a dedicated device; dealt with the impact of SUV on survival. We extracted an estimate of the log hazard ratios (HR) and their variances and performed meta-analysis.

RESULTS

Without the study dealt by the pretreatment SUV measured on metastasis sites, there were seven studies dealt by the prognostic value of SUV measured on FDG-PET for overall survival. The combined HR was 1.86, meaning that high SUV indicated worse survival prognosis; and there were three studies dealt with the prognostic value of SUV measured on FDG-PET for disease-free survival. The combined HR was 2.52, indicating that high SUV was associated with more significantly higher risk for recurrence than low SUV.

CONCLUSION

SUV measured in patients with esophageal cancer, reflecting the metabolic activity of tumor and malignancy, could serve as a prognostic factor. Considering that the FDG-PET can add important information of metabolism in detection and staging to conventional imaging modality, we anticipate that SUV could be used in patients with esophageal carcinoma.

The clinical application of (18)F-fluorodeoxyglucose positron emission tomography to predict survival in patients with operable esophageal cancer

BACKGROUND

Metabolic tumor activity using (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) was believed to have a predictive value for patient outcome in malignancies. The objective of the current study was to assess the prognostic effectiveness of the highest standardized uptake value (SUV) in the primary or regional area (peak SUV) and the number of PET-positive lymph nodes in esophageal cancer.

METHODS

The authors retrospectively reviewed their experience with 184 consecutive esophageal cancer patients imaged preoperatively using FDG-PET scanning.

RESULTS

The median peak SUV was 4.5 (range, 1.4-21.9). The survival curve was analyzed using the median peak SUV as the cutoff value. Comparison of each group and clinicopathologic characteristics revealed significant associations between peak SUV and each of the following factors: tumor status (P < .001), lymph node status (P < .001), metastatic status (P < .05), stage of disease (P < .001), number of PET-positive lymph nodes (P < .001), and the number of histologically positive lymph nodes (P < .001). The 5-year overall survival (OS) rate for patients having FDG uptake with a peak SUV > or =4.5 was 47% and that for patients with a peak SUV <4.5 was 76% (P < .0001). On multivariate survival analysis using the Cox proportional hazards model, peak SUV and the number of PET-positive lymph nodes were found to be independent predictive factors for OS. The number of PET-positive lymph nodes was a single prognostic factor predicting both disease-free survival and OS.

CONCLUSIONS

Pretreatment PET cannot only potentially diagnose the extent of disease, but also may be predictive of patient survival after esophageal cancer resection.

Monitoring response to therapeutic interventions in patients with cancer

Positron emission tomography (PET) and PET/computed tomography (CT) with the glucose analog (18)F-fluorodeoxyglucose (FDG) are increasingly used to assess response to therapy in patients, and there is converging evidence that changes in glucose utilization during therapy can be used to predict clinical outcome. Today, integrated PET/CT systems have mainly replaced stand-alone PET devices, providing the opportunity to integrate morphologic information and functional information. However, the use of PET/CT systems also gives rise to methodological challenges for the quantitative analysis of PET scans for treatment monitoring. Recently published single-center studies demonstrate that FDG-PET and FDG-PET/CT have been successfully used for monitoring of tumor response to cytotoxic therapy in a variety of tumor entities. The potential early identification of nonresponding tumors provides an opportunity to alter treatment regimens according to the individual chemosensitivity of the tumor tissue. In this article, we review the methodological background to monitoring of cancer treatment with PET/CT, the diagnostic and prognostic performance of PET/CT for predicting tumor response with the glucose analog FDG in various tumor entities, and the clinical potential of new imaging probes. In addition, the future direction of research and clinical applications is discussed.

Impact of fluorodeoxyglucose PET on the management of esophageal cancer

Esophageal cancer is the third most common malignancy of the alimentary tract. The incidence of esophageal cancer has steadily increased over the past three decades. Almost all therapeutic modalities for esophageal cancer are associated with a considerable mortality and morbidity. Consequently, there has been growing concern regarding effective management of esophageal cancer. 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) is playing an increasing role in the management of esophageal cancer, offering potential advantages in the accuracy of disease assessment at a number of decision points in the management pathway. This review evaluates the critical role of FDG-PET in (i) diagnosis, (ii) preoperative staging, (iii) monitoring of response to neoadjuvant therapy, (iv) assessment of recurrence and (v) prediction of prognosis of esophageal cancer. We have also compared diagnostic performance of FDG-PET and other current technologies such as computed tomography scan and endoscopic ultrasonography based on available evidence.

Proteomic and metabolic prediction of response to therapy in gastrointestinal cancers

Despite substantial improvements in the diagnosis and treatment of many gastrointestinal cancers, particularly colorectal cancer, numerous patients are only diagnosed in advanced stages of disease, which can preclude curative treatment. Screening and early diagnosis of high-risk individuals might be the most promising approach to improve prognosis; however, molecular biomarkers for early diagnosis of most gastrointestinal cancers are not yet available. The prognosis of patients with advanced gastrointestinal cancers has improved through the development of multimodal treatments and the introduction of targeted therapies. Nonetheless, not all patients benefit equally from these treatment approaches, and toxicity can be substantial. The ability to predict whether a patient will respond to therapy early in their treatment for gastrointestinal cancer may be of particular value to stratify and individualize patient treatment strategies. Despite improvement in the understanding of cancer pathogenesis and progression at the molecular level, the molecular changes that underlie treatment response and/or drug resistance are still largely unknown. PET is the first technique to show promise in prediction of response to therapy, and has resulted in promising advancements, particularly in esophageal and gastric cancers. Tissue-based and blood-based molecular biomarkers are still subject to validation. Prediction of response to treatment could ultimately lead to an overall improvement in prognosis.