A prospective evaluation of the impact of 18-F-fluoro-deoxy-D-glucose positron emission tomography staging on survival for patients with locally advanced esophageal cancer

High expression of HNRNPR in ESCA combined with 18F-FDG PET/CT metabolic parameters are novel biomarkers for preoperative diagnosis of ESCA

Background

The aim of this study was to determine the expression and function of heterogeneous nuclear ribonucleoprotein R (HNRNPR) in esophageal carcinoma (ESCA), the correlation between its expression and ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computerized tomography scan (PET/CT)-related parameters. We also investigated whether ¹⁸F-FDG PET/CT can be used to predict the expression of HNRNPR in ESCA.

Methods

We analyzed patients with ESCA who underwent ¹⁸F-FDG PET/CT before surgery, and their tissues were stained with HNRNPR IHC. The associated parameters were derived using the ¹⁸F-FDG PET imaging data, and the correlation with the IHC score was evaluated. The Oncomine, TCGA, and GEO datasets were used to investigate HNRNPR expression in the pan- and esophageal cancers, as well as its relationship with N6-methyladenosine (m6A) modification and glycolysis. The R software, LinkedOmics, GeneMANIA, and StringOnline tools were used to perform GO/KEGG, GGI, and PPI analyses on the HNRNPR.

Results

HNRNPR is highly expressed in the majority of pan-cancers, including ESCA, and is associated with BMI, weight, and history of reflux in patients with ESCA. HNRNPR is somewhat accurate in predicting the clinical prognosis of ESCA. HNRNPR expression was positively correlated with SUV_max, SUV_mean, and TLG in ESCA (p < 0.05). The combination of these three variables provides a strong predictive value for HNRNPR expression in ESCA. GO/KEGG analysis showed that HNRNPR played a role in the regulation of cell cycle, DNA replication, and the Fannie anemia pathway. The analysis of the TCGA and GEO data sets revealed a significant correlation between HNRNPR expression and m6A and glycolysis-related genes. GSEA analysis revealed that HNRNPR was involved in various m6A and glycolysis related-pathways.

Conclusion

HNRNPR overexpression correlates with ¹⁸F-FDG uptake in ESCA and may be involved in the regulation of the cell cycle, m6A modification, and cell glycolysis. ¹⁸F-FDG PET/CT-related parameters can predict the diagnostic accuracy of HNRNPR expression in ESCA.

Prognostic significance of PET assessment of metabolic response to therapy in oesophageal squamous cell carcinoma

Objectives:

The role of maximum standard uptake value (SUVmax) at baseline and after induction chemotherapy (CT) on positron emission tomography (PET) as an imaging biomarker has not been well established in oesophageal squamous cell carcinoma (SCC). In this retrospective analysis, we investigated the prognostic significance of various PET metrics in oesophageal SCC patients treated with induction chemotherapy followed by concurrent chemoradiotherapy (CRT).

Methods:

A total of 57 patients were treated with CRT; 52 patients received induction chemotherapy and 10 patients underwent surgery following CRT. Scans were independently analysed by a nuclear medicine physician blinded to patient outcome. Using region of interest analysis, SUVmax and metabolic tumour volume (MTV) were calculated for the index lesion and lymph node metastases in each patient. Kaplan–Meier analysis was used to evaluate overall survival (OS), disease-free survival (DFS), local recurrence-free survival (LRFS) and distant metastasis-free survival (DMFS). Cox proportional hazards regression was used to assess correlation between outcomes and PET metrics.

Results:

Median follow-up for those who are alive was 4.4 years, with a median survival for all patients of 2.9 years. The 3-year OS, DFS, DMFS and LRFS rates were 47, 40, 44 and 36%, respectively. Using a pre-established cutoff of a 35% decrease in SUVmax from baseline to post-induction PET, 3-year OS for responders (⩾35% decrease from baseline) was 64%, whereas non-responders (<35% decrease from baseline) had a 3-year OS of 15% (P=0.004).

Conclusions:

The pre-specified 35% decrease in SUVmax after induction chemotherapy was prognostic for OS. Baseline and post-induction PET metrics provide prognostic information for oesophageal SCC.

Esophageal cancer management: preoperative CA19.9 and CEA serum levels may identify occult advanced adenocarcinoma

BACKGROUND

Esophagectomy is contraindicated in case of advanced cancer (i.e., carcinomatosis, distant metastasis, and invasion of other organs). In some cases, preoperative imaging may fail to identify advanced neoplasm and esophagectomy is inappropriately planned. The aim of the study was to identify preoperative biomarkers of occult advanced disease that force surgeons to abort the planned esophagectomy.

METHODS

From 2008 to 2014, 244 consecutive patients were taken to the operative room to have esophagectomy for cancer in our department. All of them had blood test at admission and their preoperative biomarker data were retrieved. Their medical history was collected and the intraoperative findings and outcome were recorded. Non parametric tests, multiple regression analysis, and ROC curves analysis were performed.

RESULTS

In our study group, 14 (5.7 %) patients, scheduled for esophagectomy, were discovered to have occult advanced disease at laparotomy/laparoscopy or at thoracotomy. Six of them had peritoneal carcinomatosis, three had advanced tumor invading other organs, three had small liver metastasis, and two pleural carcinomatosis. In all these cases, esophagectomy was aborted and a feeding jejunostomy was placed. In patients with unresectable esophageal cancer, CA19.9 and CEA serum levels were significantly higher than patients who could have esophagectomy (p < 0.001 and p = 0.003, respectively). CA19.9 and CEA resulted to be accurate biomarkers of occult advanced disease (AUC = 85 %, p < 0.001 and AUC = 73 %, p = 0.002, respectively).

CONCLUSIONS

Preoperative CEA and CA19.9 serum levels should be taken in consideration when evaluating patients candidate to esophagectomy for esophageal cancer to prevent inappropriate laparotomy or thoracotomy. If any doubt arises minimally invasive exploration is warranted.

Introduction to the analysis of PET data in oncology

Several reviews on specific topics related to positron emission tomography (PET) ranging in complexity from introductory to highly technical have already been published. This introduction to the analysis of PET data was written as a simple guide of the different phases of analysis of a given PET dataset, from acquisition to preprocessing, to the final data analysis. Although sometimes issues specific to PET in neuroimaging will be mentioned for comparison, most of the examples and applications provided will refer to oncology. Due to the limitations of space we couldn't address each issue comprehensively but, rather, we provided a general overview of each topic together with the references that the interested reader should consult. We will assume a familiarity with the basic principles of PET imaging.

Symptomatic cardiac toxicity is predicted by dosimetric and patient factors rather than changes in 18F-FDG PET determination of myocardial activity after chemoradiotherapy for esophageal cancer

PURPOSE

To determine factors associated with symptomatic cardiac toxicity in patients with esophageal cancer treated with chemoradiotherapy.

MATERIAL AND METHODS

We retrospectively evaluated 102 patients treated with chemoradiotherapy for locally advanced esophageal cancer. Our primary endpoint was symptomatic cardiac toxicity. Radiation dosimetry, patient demographic factors, and myocardial changes seen on (18)F-FDG PET were correlated with subsequent cardiac toxicity. Cardiac toxicity measured by RTOG and CTCAE v3.0 criteria was identified by chart review.

RESULTS

During the follow up period, 12 patients were identified with treatment related cardiac toxicity, 6 of which were symptomatic. The mean heart V20 (79.7% vs. 67.2%, p=0.05), V30 (75.8% vs. 61.9%, p=0.04), and V40 (69.2% vs. 53.8%, p=0.03) were significantly higher in patients with symptomatic cardiac toxicity than those without. We found the threshold for symptomatic cardiac toxicity to be a V20, V30 and V40 above 70%, 65% and 60%, respectively. There was no correlation between change myocardial SUV on PET and cardiac toxicity, however, a greater proportion of women suffered symptomatic cardiac toxicity compared to men (p=0.005).

CONCLUSIONS

A correlation did not exist between percent change in myocardial SUV and cardiac toxicity. Patients with symptomatic cardiac toxicity received significantly greater mean V20, 30 and 40 values to the heart compared to asymptomatic patients. These data need validation in a larger independent data set.

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

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

METHODS

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

RESULTS

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

CONCLUSION

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

Esophageal carcinoma advances in treatment results for locally advanced disease: review

The treatment results of patients with locally advanced esophageal carcinomas have evolved since the publication of the first trial of concurrent mitomycin C and 5-fluorouracil with radiotherapy (RT) in 1983. Subsequent studies refined and improved on the concurrent chemotherapy (chemo) with administration of cisplatin and 5-fluorouracil infusion (PF). Chemo (PF) before surgery improved overall survival (OS) in those patients in most of the randomized trials and in meta-analyses. Two courses of PF concurrent with irradiation followed by additional two courses of PF were superior to RT alone without surgery for both groups. Concurrent chemoradiotherapy followed by surgery was found to have statistically improved OS as compared with surgery only in randomized trials and meta-analyses. In most of these studies, it was found that those patients with pathologic complete response to the initial treatment(s) did better than those who had no improvement at all. Current treatment outcome for these diseases is disappointing; newer strategies including induction chemo with the optimal combination, proper dosage of each drug, and proper number of courses before concurrent chemoradiotherapy; improvement in RT; and immunotherapy with or without subsequent surgery are exciting and definitely need to be investigated in prospective randomized trial(s).

The influence of Hispanic ethnicity on nonsmall cell lung cancer histology and patient survival: an analysis of the Survival, Epidemiology, and End Results database

BACKGROUND

Most studies exploring ethnic/racial disparities in nonsmall cell lung cancer (NSCLC) compare black patients with whites. Currently, the effect of Hispanic ethnicity on the overall survival of NSCLC is poorly understood. Therefore, the authors carried out a large-scale, population-based analysis using the Surveillance, Epidemiology, and End Results (SEER) data base to determine the impact of Hispanic ethnicity the survival of patients with NSCLC.

METHODS

The authors identified 172,398 adult patients with pathologically confirmed NSCLC from the SEER data base who were diagnosed between 1988 and 2007. A multivariate Cox proportional hazards regression analysis was used to determine the impact of race/ethnicity on overall survival. Pair-wise comparisons were used to determine whether Hispanic ethnicity influenced NSCLC histology or stage at diagnosis.

RESULTS

Compared with non-Hispanic white patients, Hispanic white patients had a statistically significant better overall survival (hazard ratio [HR], 0.85; 95% confidence interval [CI], 0.83-0.87), and black patients had worse survival (HR, 1.091; 95% CI, 1.072-1.109). Within the bronchioalveolar carcinoma (BAC) subtype, Hispanic-white patients tend to be over represented (8.1% Hispanic whites vs 5.5% non-Hispanic whites vs 3.7% blacks; P < .001).

CONCLUSIONS

The current study demonstrated that Hispanic-white patients with NSCLC had a decreased risk for overall mortality compared with non-Hispanic whites and blacks. Moreover, Hispanic patients were over represented within the BAC histologic subtype. Thus, the overall survival advantage of Hispanic NSCLC patients may be because of their predilection toward developing certain histologic subtypes of NSCLC. Further studies are warranted to determine the etiologies of such predilections and may reveal certain genetic, environmental, and/or epigenetic factors associated with Hispanic ethnicity.

Prognostic significance of baseline positron emission tomography and importance of clinical complete response in patients with esophageal or gastroesophageal junction cancer treated with definitive chemoradiotherapy

BACKGROUND

Metabolic imaging is of interest in esophageal cancer; however, the usefulness of initial standardized uptake value (SUV) in positron emission tomography (PET) is unknown in patients with esophageal or gastroesophageal carcinoma treated with definitive chemoradiotherapy. The authors hypothesized that initial SUV would correlate with patient outcome.

METHODS

The authors retrospectively analyzed esophageal or gastroesophageal carcinoma patients who had baseline PET and endoscopic ultrasonography in addition to other routine staging. All patients received definitive chemoradiotherapy. Multiple statistical methods were used.

RESULTS

The authors analyzed 209 consecutive esophageal or gastroesophageal carcinoma patients treated with definitive chemoradiation for outcome; of these, 180 had baseline PET for additional analyses. The median overall survival (OS) for all patients was 20.7 months (95% confidence interval, 18.8-26.3). Patients with clinical complete response (CR) lived longer than those with less than clinical CR (P < .0001). The median initial SUV was 12.7 (range, 0-51). Higher initial SUV was associated with longer tumors (P = .0001), higher T-stage status (P < .0001), positive N-stage status (P = .0001), higher overall stage (P < .0001), lack of clinical CR (P = .0002), and squamous cell histology (P < .0001). In the univariate analysis, initial SUV was associated with OS (Cox model, P = .016; log-rank test, P = .002). In the multivariate analysis, initial SUV dichotomized by the median value (P = .024) and tumor grade (P = .016) proved to be independent OS prognosticators. Median initial SUV for clinical CR patients was 10.2, compared with 15.3 for less than clinical CR patients (P = .0058).

CONCLUSIONS

The data indicate that a higher initial SUV is associated with poorer OS in patients with esophageal or gastroesophageal carcinoma receiving definitive chemoradiation. Upon validation, baseline PET may become a useful stratification factor in randomized trials and for individualizing therapy.

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

PURPOSE

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSION

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

Can hybrid FDG-PET/CT detect subclinical lymph node metastasis of esophageal cancer appropriately and contribute to radiation treatment planning? A comparison of image-based and pathological findings

BACKGROUND

We aimed to determine the appropriateness of adding 18F-fluorodeoxyglucose (FDG)-positronemission tomography (PET) to computed tomography (CT) and other pre-existing diagnostic imaging modalities for detecting subclinical lymph node metastasis of esophageal cancer, by comparing images from these modalities with the results of histopathological analysis.

METHODS

Twenty patients who received radical surgery for squamous cell carcinoma of the esophagus were examined by PET-CT, and endoscopic ultrasound (EUS) examination before surgery. Based on these diagnostic modalities, the clinical target volume (CTV) was set as the gross tumor volume (GTV) plus a 1-cm margin. Histopathological diagnosis was performed in all patients immediately after resection.

RESULTS

Fifty-three (3.0%) of 1764 nodes in the 20 patients were histopathologically positive for cancer cells. The CTV was not adequate to cover these histopathologically detected positive lymph nodes in 8 of 20 patients on CT, 5 of 20 on CT+EUS, 7 of 20 on PET-CT, and 5 of 20 on PET-CT+EUS.

CONCLUSION

The detection rate of subclinical lymph node metastasis did not improve with the use of PET-CT, for either the cervical and supraclavicular, mediastinal, or abdominal regions. It is not recommended to use FDG-PET or PET-CT alone as a diagnostic tool to determine CTV if pathologically involved lymphatic regions are to be included in the CTV in the treatment protocol. The accuracy of PET-CT must be further improved in order to better detect positive nodes and improve the definition of the CTV.

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.

Positron emission tomography changes management and prognostic stratification in patients with oesophageal cancer: results of a multicentre prospective study

OBJECTIVES

The aims of this study were (1) to determine the incremental information provided by (18)F-FDG positron emission tomography (PET) in staging patients with oesophageal cancer, and (2) to determine the impact of PET staging on post-PET clinical management of oesophageal cancer, and on prognosis.

METHODS

In a multicentre, single-arm open study, patients with proved oesophageal cancer without definite distant metastases and regarded as suitable for potentially curative treatment were examined by PET. Clinicians were requested to supply a management plan before and another plan after being supplied with the PET scan results. Patients were followed for at least 1 year for outcome analysis.

RESULTS

A total of 129 patients (104 men, mean age 67 y) were recruited. PET detected additional sites of disease in 53 patients (41%). Significant changes in management (high or medium impact) were observed in 38% of patients, primarily as a result of identifying additional sites of disease and/or confirming previously equivocal regional and distant metastases. Progression-free survival was significantly shorter in patients found to have additional lesions on PET (p < 0.05), but was not related to SUV(max).

CONCLUSION

These findings demonstrate the significant impact of PET on the clinical management of patients with newly diagnosed oesophageal carcinoma, and on prognostic stratification of these patients.

Staging esophageal cancer

Accurate staging of disease is necessary in patients with newly diagnosed esophageal cancer in order to prompt appropriate curative or palliative therapy. Computed tomography (CT) may be used to evaluate for local spread into adjacent structures (T4 disease) and to diagnose distant metastases (M1). Endoscopic ultrasonography (EUS) is the modality of choice for distinguishing T1 tumors from higher stage lesions and for detecting and sampling regional lymph nodes (N1 disease). Positron emission tomography (PET) scanning is most helpful for detecting previously occult distant metastases. Optimal staging generally requires a multimodality approach.

Prognostic value of initial fluorodeoxyglucose-PET in esophageal cancer: a prospective study

OBJECTIVES

Esophageal cancer outcome greatly depends on the pathological stage. Our objectives were to assess prognosis on the basis of the initial fluorodeoxyglucose (FDG)-PET scan, focusing on the correlation between overall survival and FDG uptake in the primary, as well as the presence of FDG-positive lymph nodes or distant metastases.

METHODS

Fifty-two esophageal cancer patients undergoing FDG-PET as part of initial routine staging procedure before treatment were included. The maximum standardized uptake value (SUV max) was determined in each primary lesion and the number of abnormalities including primary, lymph nodes, or distant metastases was recorded. Correlation with overall survival was performed using Kaplan-Meier method and Cox regression analysis was used to assess the prognostic value of PET parameters.

RESULTS

Half of the patients were planned for initial curative surgery (52%). Using univariate survival analysis, either surgery, SUV max >9, two or more PET abnormalities or the presence of FDG-positive nodes were significant overall survival prognostic predictors. After multivariate analysis, only SUV max >9 and FDG-positive lymph nodes were found as independent predictors of poor outcome.

CONCLUSION

In this prospective study, FDG-PET was found to provide prognostic information supporting a new indication for initial FDG-PET examination in esophageal cancer.

Role of PET/PET CT in the staging and restaging of thoracic oesophageal cancer and gastro-oesophageal cancer: a literature review

BACKGROUND

Current evidence for the use of FDG PET/PET-CT in staging thoracic oesophageal and GOJ cancer is reviewed.

METHODS

PubMed, Medline, Embase (1988-November 2006) and the Cochrane database identified studies in which FDG PET and PET CT were used for the assessment of thoracic and GOJ cancer.

RESULTS

Conventional assessment remains the mainstay for evaluating the primary site. EUS is used for assessing the primary site, but when EUS is incomplete or not tolerated FDG PET CT is invaluable. The major of advantage of FDG PET CT lies in the ability to detect metastatic disease beyond the celiac axis. There is growing evidence to show that FDG PET CT is useful for assessment of treatment response. FDG PET CT will also detect other occult primary cancers.

CONCLUSIONS

The contribution of FDG PET CT to the investigation of patients with primary thoracic oesophageal and GOJ cancer has resulted in improved staging, so providing the ability to optimise treatment.

The role of integrated computed tomography positron-emission tomography in esophageal cancer: staging and assessment of therapeutic response

Computed tomography (CT) and endoscopy/endoscopic ultrasonography are usually performed to initially stage patients with esophageal cancer, to determine primary tumor response, and to detect nodal and distant metastases after preoperative therapy. Positron-emission tomography (PET) with [18F]-fluoro-2-deoxy-D-glucose and integrated CT-PET are useful in the initial staging of patients with esophageal cancer as well as in the prediction of pathologic response, disease-free interval, and overall survival after preoperative therapy. Importantly, integrated CT-PET imaging decreases the number of futile attempts at surgical resection, mainly because of the detection of occult distant metastases. The following sections review the use of integrated CT-PET imaging in determining the T, N, and M descriptors of the American Joint Commission on Cancer's 2002 guidelines for pathologic and clinical staging at initial diagnosis and after chemoradiation therapy in those patients being considered for surgical resection.

PET: other thoracic malignancies

The vast majority of esophageal cancers are fluorodeoxyglucose (FDG) avid; the primary use for positron emission tomography (PET) in patients with esophageal cancer is in the detection of distant metastases, because known distant metastatic disease precludes surgical resection. High standardized uptake values (SUVs) may be predictive of poor prognosis. PET findings may be used to assess therapy response and evaluate for esophageal tumor recurrence after treatment. PET findings may be non-specific in different types of thymic lesions, although thymic carcinomas tend to be extremely FDG avid. PET can be helpful in detecting distant spread from invasive thymomas and thymic carcinomas. Similarly, PET may be used to assess the extent of disease in patients with malignant pleural mesothelioma, thereby facilitating optimal therapy approaches.

Radiological staging of gastrointestinal and breast tumours

Combining morphology and metabolism