An analysis of multiple staging management strategies for carcinoma of the esophagus: computed tomography, endoscopic ultrasound, positron emission tomography, and thoracoscopy/laparoscopy

Current staging of esophageal carcinoma

The rational treatment of esophageal cancer requires the complete evaluation and preoperative staging of this disease. As the incidence of esophageal cancer increases, more clinicians will face the difficult task of allocating the appropriate treatment course for these patients. Accurate esophageal cancer staging is critical if stage-dependent algorithms are used to direct appropriate therapies. Although all of the staging techniques discussed may potentially provide useful information, it is not possible to use all techniques in all patients, especially given the limited availability of resources. The optimal staging strategy has not yet been determined; the authors provide the general algorithm used in our institution. Ultimately,minimally invasive surgical approaches will allow surgeons to evaluate locoregional disease with little or no procedure-associated morbidity, much as mediastinoscopy is used in lung cancer staging. Although currently the use of molecular biologic techniques may only be investigational, it holds great promise in the future.

Role of endoscopic ultrasonography in the staging and follow-up of esophageal cancer

PURPOSE

To evaluate the role of endoscopic ultrasonography (EUS) in the initial staging and follow-up of esophageal cancer on the basis of a review of the published literature.

METHODS

Articles published from 1985 to 2005 were searched and reviewed using the following keywords: "esophageal cancer staging," "endoscopic ultrasound," and "endoscopic ultrasonography."

RESULTS

For initial anatomic staging, EUS results have consistently shown more than 80% accuracy compared with surgical pathology for depth of tumor invasion (T). Accuracy increased with higher stage, and was >90% for T3 cancer. EUS results have shown accuracy in the range of 75% for initial staging of regional lymph nodes (N). EUS has been invariably more accurate than computed tomography for T and N staging. EUS is limited for staging distant metastases (M), and therefore EUS is usually performed after a body imaging modality such as computed tomography or positron emission tomography. Pathologic staging can be achieved at EUS using fine-needle aspiration (FNA) to obtain cytology from suspect Ns. FNA has had greatest efficacy in confirming celiac axis lymph node metastases with more than 90% accuracy. EUS is inaccurate for staging after radiation and chemotherapy because of inability to distinguish inflammation and fibrosis from residual cancer, but a more than 50% decrease in tumor cross-sectional area or diameter has been found to correlate with treatment response.

CONCLUSION

EUS has a central role in the initial anatomic staging of esophageal cancer because of its high accuracy in determining the extent of locoregional disease. EUS is inaccurate for staging after radiation therapy and chemotherapy, but can be useful in assessing treatment response.

Endoscopic ultrasound for luminal malignancies

Luminal gastrointestinal (GI) tract cancers are responsible for substantial morbidity and mortality. Since the first pairing of ultrasonography with endoscopy in 1980, technologic advances and the increased availability of trained endosonographers have propelled endoscopic ultrasonography (EUS) to the forefront of luminal GI cancer staging. In this article we discuss the role of EUS for evaluating luminal GI cancers.

The additional value of PET/CT over PET in FDG imaging of oesophageal cancer

PURPOSE

The aim of this study was to assess the value of combined PET/CT compared with PET reviewed side-by-side with CT, in patients with oesophageal cancer, before and after surgery.

METHODS

Forty-one FDG PET/CT studies were performed in 32 patients with oesophageal cancer, before surgery (n = 18) or during follow-up after resection of the primary tumour (n = 23). One hundred and fifteen sites suspicious for malignancy were evaluated. PET/CT was prospectively compared with PET reviewed side-by-side with CT, for detection, accurate localisation and characterisation of malignant sites. PET/CT performance in different anatomical regions was compared before and after surgery. The impact of fused data on patient management was retrospectively assessed.

RESULTS

PET/CT had an incremental value over PET for interpretation of 25 of 115 sites (22%), changing the initial characterisation of ten sites to either malignant (n = 1) or benign (n = 9), and defining the precise anatomical location of 15 sites. PET/CT provided better specificity and accuracy than PET for detecting sites of oesophageal cancer (81% and 90% vs 59% and 83% respectively, p < 0.01). Fusion was of special value for interpretation of cervical and abdomino-pelvic sites, for disease assessment in loco-regional lymph nodes before surgery and in regions of postoperative anatomical distortion. PET/CT had an impact on the further management of four patients (10%), by detecting nodal metastases that warranted disease upstaging (n = 2) and by excluding disease in sites of benign uptake after surgery (n = 2).

CONCLUSION

PET/CT improves the accuracy of FDG imaging in oesophageal cancer and provides data of diagnostic and therapeutic significance for further patient management.

Detection of lymph node micrometastases by gene promoter hypermethylation in samples obtained by endosonography- guided fine-needle aspiration biopsy

Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) has become a fundamental procedure for gastrointestinal and lung cancer staging. However, there is growing evidence that micrometastases are present in lymph nodes, which cannot be detected with standard pathological methods. The aim of this study was to evaluate whether hypermethylation gene promoter analysis was feasible on samples obtained by EUS-FNA from lymph nodes, as well as to establish the usefulness of this strategy for the detection of micrometastases in patients with gastrointestinal and non-small cell lung cancer. Suspicious lymph nodes based on EUS findings from consecutive patients with esophageal, gastric, rectal, and non-small cell lung cancer were sampled by EUS-FNA. Hypermethylation analysis of the MGMT, p16(INK4a), and p14(ARF) gene promoter CpG islands were performed by methylation-specific PCR. Effectiveness of conventional cytology, methylation analysis, and their combination were established with respect to the definitive diagnosis. Twenty-seven patients were included, thus representing a total of 42 lymph nodes (esophageal cancer, n = 11; rectal cancer, n = 7; gastric cancer, n = 3; and lung cancer, n = 21). According to definitive diagnosis, 21 (50%) corresponded to metastatic lymph nodes. Sensitivity, specificity, and overall accuracy of conventional cytology were 76%, 100%, and 88%, respectively, whereas the corresponding values for the methylation analysis were 81%, 67%, and 74%, respectively. Combination of both techniques increased sensitivity (90%) but decreased specificity (67%) with respect to conventional cytology. In conclusion, it is feasible to detect occult neoplastic cells in EUS-FNA samples by hypermethylation gene promoter analysis. Moreover, addition of methylation analysis to conventional cytology may increase its sensitivity at the expenses of a decrease in its specificity.

Diagnostic radiology and nuclear medicine

The diagnosis and accurate staging of esophageal adenocarcinoma remains one of the greatest challenges for non-invasive imaging techniques. All modalities have limitations and require a rational application of combined tools in order to assess the extent of loco-regional tumor and distant metastatic disease. The fundamental role remains defining organ-confined disease and mapping non-organ confined disease. Endoscopic ultrasound combined with multislice computed tomography (CT) is the mainstay of morphologic loco-regional staging. In recent years, functional metabolic 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG)-positron emission tomography (PET) has emerged as a particularly useful adjunct to detect occult metastatic disease, to predict response to neoadjuvant therapy and to document recurrent disease. The current imaging algorithm and new developments in imaging assessment will be reviewed.

Noninvasive competition for endoscopic ultrasound

Endoscopic ultrasonography (EUS) is one of the most significant developments in gastrointestinal (GI) imaging in recent years. EUS now plays a key role in the pretreatment staging of GI tract tumors and in the investigation of benign pancreaticobiliary pathology. It has not replaced conventional cross-sectional imaging (eg, ultrasound, CT, and MRI), but it has distinct properties and capabilities. EUS is most beneficial when used in a complementary fashion with cross-sectional and radionuclide imaging in the management of patients with GI tract disease. This article reviews the role of noninvasive imaging modalities in several clinical situations where EUS plays a prominent role.

Technology Insight: current status of endoscopic ultrasonography

Endoscopic ultrasound (EUS) has become the most accurate imaging modality for locoregional cancer staging of the gastrointestinal tract. Fine-needle aspiration (FNA) has added a new level of accuracy for EUS in nodal staging, with reported numbers in the 90% range for luminal and pancreaticobiliary disease. In addition, new non-gastrointestinal applications are being evaluated, such as the role of EUS-FNA for the staging of non-small-cell lung cancer and exploration of the posterior mediastinum. Furthermore, the same techniques that make safe tissue sampling possible are being explored for their use as interventional applications, such as EUS-guided celiac plexus neurolysis, fine-needle injection, EUS-guided pseudocyst drainage, and EUS-guided cholangiography and pancreatography. This review describes the current clinical status of EUS in gastrointestinal oncology, as well as future and novel indications and therapeutic strategies for this technology.

PET imaging in assessing gastrointestinal tumors

The clinical usefulness of FDG-PET imaging is now firmly established in various situations, such as the preoperative staging of esophageal cancer and recurrent colorectal carcinoma and the detection and staging of recurrent colorectal cancer when there is a clinical or biologic suspicion with inconclusive conventional findings. Encouraging results were obtained in the evaluation of the therapeutic response of various gastrointestinal malignancies, either during the treatment or after its completion. There is no firm consensus regarding its role in pancreatic cancer, either proved or suspected, but it may be valuable in selected clinical situations. Its role seems fairly limited in patients with hepatocellular carcinoma, although PET findings may have prognostic implications. Evaluation of cholangiocarcinoma is an emerging indication, albeit with limited data to date. Finally, PET/CT is very likely to enhance the role of FDG imaging further in the work-up of patients with gastrointestinal tumors.

Systematic review of the staging performance of 18F-fluorodeoxyglucose positron emission tomography in esophageal cancer

PURPOSE

Despite the increasing number of publications concerning (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) for staging of esophageal cancer and the increasing availability of this novel diagnostic modality, its exact role in preoperative staging of these tumors is still unknown. The aim of this study was to systematically review the literature regarding the diagnostic performance of FDG-PET in preoperative staging of patients with esophageal cancer, and to calculate summary estimates of its sensitivity and specificity.

METHODS

The databases of PubMed, Embase, and Cochrane were searched for relevant studies. Two reviewers independently assessed the methodological quality of each study. A meta-analysis of the reported sensitivity and specificity of each study was performed.

RESULTS

Twelve studies met the inclusion criteria. The studies had several design deficiencies. Pooled sensitivity and specificity for the detection of locoregional metastases were 0.51 (95% CI, 0.34 to 0.69) and 0.84 (95% CI, 0.76 to 0.91), respectively. For distant metastases, pooled sensitivity and specificity were 0.67 (95% CI, 0.58 to 0.76) and 0.97 (95% CI, 0.90 to 1.0), respectively.

CONCLUSION

FDG-PET showed moderate sensitivity and specificity for the detection of locoregional metastases, and reasonable sensitivity and specificity in detection of distant lymphatic and hematogenous metastases.

Detection and staging of esophageal cancers

PURPOSE OF REVIEW

Technology for detection and staging of esophageal cancer has made significant strides advances in the past 2 years. These advances have led to the enhanced selection of appropriate treatments for esophageal cancer. Cancers that are discovered at an early stage can be treated with endoscopic therapy, whereas advanced cancers are primarily treated with chemotherapy and radiation.

RECENT FINDINGS

Detection of esophageal cancer can be enhanced by two major mechanisms: one is by enhancing the lesion, which has typically been done using vital dyes and the other is by changing the method of imaging of the lesion, which has been accomplished by the use of several technologies including fluorescence and optical coherence tomography. Neither of these techniques has been proven, but some investigators have been able to use them to enhance cancer detection. Similar technologies have been applied to staging esophageal cancer. The optical imaging devices also have the potential to stage mucosa-based malignancy. The use of positron emission tomography has been the most recent development that may have application for advanced cancer. Endoscopic ultrasonography has also been improved in resolution and ability to perform fine needle aspiration. The most significant development for staging early cancers is mucosal resection. Finally, by using mucosal resection techniques, the depth of tumor invasion can be established by histology, which allows gastroenterologists to treat early cancers with greater confidence regarding rates of metastatic disease.

SUMMARY

Early detection of esophageal cancer can be enhanced by the use of vital dyes for mucosal staining, but the advancement of novel optical diagnostic strategies may be more suitable for clinical use. The primary advantage of these new staging methods is to clearly identify early stage cancer that potentially can be treated without traditional surgical resection techniques. More advanced cancers can be staged with positron emission tomography, but definitive studies demonstrating its role are still lacking.

Neoplasms of the esophagus and stomach

Esophageal cancer is one of the most lethal of all neoplasms. During the last two decades, there have been significant changes in the epidemiology and treatment of esophageal cancer. The incidence of adenocarcinoma is increasing whereas that of squamous cancer is decreasing. Surgery, the mainstay of treatment of esophageal cancer, has been used with neoadjuvant chemoradiotherapy to improve prognosis in patients with localized disease. Accurate staging is essential for selection of the best mode of therapy and to predict prognosis. In addition, with widespread use of neoadjuvant therapy, accurate assessment of response to therapy has become very important because responders have better a prognosis than nonresponders. Anatomical imaging methods, such as computed tomography and endoscopic ultrasonography, that are commonly used to evaluate esophageal cancer have shortcomings in demonstrating the true extent of disease and in assessing or predicting response to therapy. Positron emission tomography (PET) with 2-[(18)F]fluoro-2-deoxy-d-glucose (FDG) has been shown to be a useful adjunct to anatomical imaging methods. For initial staging of esophageal cancer, the combination of PET and endoscopic ultrasonography with fine-needle aspiration biopsy has been suggested to be the most effective strategy. For restaging and monitoring response to therapy, FDG-PET has been shown to be superior to conventional imaging. The incidence of gastric cancer is decreasing worldwide, but it is also a highly lethal cancer. Similar to esophageal cancer, noninvasive staging of this cancer is unsatisfactory. Approximately one-third of the patients thought to have limited disease and to be candidates for surgery by conventional staging methods, are found to have advanced disease at surgery. Only a few published studies have evaluated gastric cancer with FDG-PET. These studies suggest that FDG-PET may be useful in evaluating gastric cancers of intestinal type and nonmucinous tumors.

Positron emission tomography in gastric and esophageal cancer

PURPOSE OF REVIEW

Positron emission tomography using the positron emitting glucose analogue 18F-fluorodeoxyglucose has recently emerged as a promising metabolism-based whole-body imaging tool for cancer diagnosis and follow-up. Several reports have recently appeared indicating the potential and limitations of this technique. The review limits its scope to the recent advances of 18F-fluorodeoxyglucose positron emission tomography in the clinical management of gastric and esophageal cancer.

RECENT FINDINGS

New studies have been reported on the use of 18F-fluorodeoxyglucose positron emission tomography to assess the early and late metabolic response of a gastroesophageal tumor to chemo(radiation) therapy. The metabolic response as measured by serial 18F-fluorodeoxyglucose positron emission tomography, performed before and during treatment or some weeks thereafter, can be used to predict the clinical and histopathologic response. Moreover, the metabolic positron emission tomography response seems to be related to overall and disease-free survival.

SUMMARY

Gastroesophageal 18F-fluorodeoxyglucose positron emission tomography could add significant diagnostic information to the different phases of patient management. At initial diagnosis of esophageal cancer, positron emission tomography detects more distant lymph node and organ metastases compared with conventional diagnostics, allowing a more accurate selection of the most appropriate treatment. Serial 18F-fluorodeoxyglucose positron emission tomography performed before and during chemotherapy allows early identification of nonresponding tumors. 18F-fluorodeoxyglucose positron emission tomography performed after a treatment allows accurate assessment of the residual tumor load. 18F-fluorodeoxyglucose positron emission tomography allows accurate detection and restaging of recurrent disease.

Neoadjuvant therapy for oesophagogastric cancer

BACKGROUND

The prognosis after surgery for oesophagogastric cancer remains poor.

METHODS

This review clarifies current indications for neoadjuvant therapy for oesophageal and gastric cancer. A systematic literature research and evaluation of data from international cancer meetings were carried out.

RESULTS

Recently published results of large randomized phase III trials underscore the potential value of neoadjuvant treatment for oesophagogastric cancer. However, it remains uncertain which subgroups of patients should routinely undergo preoperative therapy. Metabolic response evaluation during neoadjuvant treatment is a promising tool for the selection of responding patients.

CONCLUSION

Neoadjuvant chemotherapy is a valid option for locally advanced oesophageal and gastric cancer. In the future, more effective and better tolerated treatment strategies, tailored to the specific tumour characteristics of each individual, should be possible.

Feasibility of optimizing the dose distribution in lung tumors using fluorine-18-fluorodeoxyglucose positron emission tomography and single photon emission computed tomography guided dose prescriptions

The information provided by functional images may be used to guide radiotherapy planning by identifying regions that require higher radiation dose. In this work we investigate the dosimetric feasibility of delivering dose to lung tumors in proportion to the fluorine-18-fluorodeoxyglucose activity distribution from positron emission tomography (FDG-PET). The rationale for delivering dose in proportion to the tumor FDG-PET activity distribution is based on studies showing that FDG uptake is correlated to tumor cell proliferation rate, which is shown to imply that this dose delivery strategy is theoretically capable of providing the same duration of local control at all voxels in tumor. Target dose delivery was constrained by single photon emission computed tomography (SPECT) maps of normal lung perfusion, which restricted irradiation of highly perfused lung and imposed dose-function constraints. Dose-volume constraints were imposed on all other critical structures. All dose-volume/function constraints were considered to be soft, i.e., critical structure doses corresponding to volume/function constraint levels were minimized while satisfying the target prescription, thus permitting critical structure doses to minimally exceed dose constraint levels. An intensity modulation optimization methodology was developed to deliver this radiation, and applied to two lung cancer patients. Dosimetric feasibility was assessed by comparing spatially normalized dose-volume histograms from the nonuniform dose prescription (FDG-PET proportional) to those from a uniform dose prescription with equivalent tumor integral dose. In both patients, the optimization was capable of delivering the nonuniform target prescription with the same ease as the uniform target prescription, despite SPECT restrictions that effectively diverted dose from high to low perfused normal lung. In one patient, both prescriptions incurred similar critical structure dosages, below dose-volume/function limits. However, in the other patient, critical structure dosage from the nonuniform dose prescription exceeded dose-volume/function limits, and greatly exceeded that from the uniform dose prescription. Strict compliance to dose-volume/ function limits would entail reducing dose proportionality to the FDG-PET activity distribution, thereby theoretically reducing the duration of local control. Thus, even though it appears feasible to tailor lung tumor dose to the FDG-PET activity distribution, despite SPECT restrictions, strict adherence to dose-volume/function limits could compromise the effectiveness of functional image guided radiotherapy.

Biomarkers of esophageal adenocarcinoma and Barrett's esophagus

The rising incidence and poor prognosis of esophageal adenocarcinoma in the Western world have intensified research efforts into earlier methods of detection of this disease and its relationship to Barrett's esophagus. The progression of Barrett's esophagus to adenocarcinoma has been the focus of particular scrutiny, and a number of potential tissue and serum-based disease biomarkers have emerged. The epidemiology and pathogenesis of esophageal adenocarcinoma are outlined. Tissue biomarkers allowing risk stratification of Barrett's are reviewed as well as strategies currently being used to discover novel biomarkers that will facilitate the early detection of esophageal adenocarcinoma. Finally, the uses of biomarkers as predictive tests for targeted treatments and as surrogate endpoints in chemoprevention trials are considered.

Pitfalls of positive findings in staging esophageal cancer with F-18-fluorodeoxyglucose positron emission tomography

BACKGROUND

18-F-fluorodeoxyglucose positron emission tomography (FDG-PET) is valuable in staging of esophageal cancer. However, FDG-PET may falsely upstage patients leading to incorrect exclusion from surgical treatment. This study was performed to determine the false-positive rate and possible causes.

METHODS

The rate of false-positive lesions on FDG-PET was documented in 86 out of a group of 98 patients. Lesions were defined as false positive when pathological examination was negative or as absence of tumor activity within 6 months of follow-up. To evaluate the influence of a learning curve on the false-positive rate, the PET scans were revised recently.

RESULTS

False-positive lesions were found in 13 patients (13 of 86; 15%). FDG-PET incorrectly revealed only locoregional node metastases in 5 patients in whom surgery with curative intent was performed. Ten lesions in the other 8 patients were classified as distant organ or as nonregional node metastases (M1a/1b). Finally, 5 patients upstaged to M1a/1b underwent a curative resection. The number of false-positive lesions decreased from 16 to 5 (6%) after revision.

CONCLUSIONS

Proper interpretation of FDG-PET in staging esophageal cancer is impeded by false-positive results. Even after completion of the learning curve, positive FDG-PET findings still have to be confirmed by additional investigations.

Role of endoscopic ultrasonography in the staging of esophageal cancer: a review

PURPOSE OF REVIEW

This review summarizes the important studies, published since April 2002, on the role of endoscopic ultrasonography for staging of esophageal cancer.

RECENT FINDINGS

The loco-regional staging accuracy for esophageal cancer by endoscopic ultrasonography is superior to other currently available imaging modalities such as helical computed tomography. Endoscopic ultrasonographic staging accuracy is further enhanced by the ability to obtain guided fine needle aspiration specimens for cytology from any suspicious celiac lymph nodes. In addition to the initial staging of esophageal cancer, endoscopic ultrasonography-based measurement of reduction of tumor cross-sectional area appears to be a reliable predictor of pathologic response to initial neoadjuvant therapy. Recently published studies on the outcomes of endoscopic ultrasonography support its utility in the staging of esophageal cancer, particularly in guiding different treatment options for different stages of loco-regional involvement.

SUMMARY

Overall, endoscopic ultrasonography for staging of patients with esophageal cancer seems to be a cost-effective intervention.

The replication-competent oncolytic herpes simplex mutant virus NV1066 is effective in the treatment of esophageal cancer

BACKGROUND

The oncolytic herpes simplex-1 virus, NV1066, is a replication-competent virus that has been engineered to infect and lyse tumor cells selectively and to carry a transgene for enhanced green fluorescent protein (EGFP). The purpose of this study was to determine viral cytotoxicity in an esophageal cancer cell line and to determine whether EGFP expression could be used as a marker of viral infection.

METHODS

BE3 esophageal adenocarcinoma cells were infected with NV1066 in vitro to determine cell kill and viral replication. EGFP expression was assessed by flow cytometry. The in vivo anti-tumor activity of NV1066 was tested in subcutaneous and intraperitoneal xenograft models. EGFP expression was localized in vivo by fluorescent microscopy and fluorescent laparoscopy.

RESULTS

NV1066 effectively replicated within and killed BE3 cells in vitro and in vivo. EGFP expression identified infected tumor cells. After NV1066 treatment in vivo, EGFP expression localized to the tumor. In an intraperitoneal tumor model, EGFP could be visualized endoscopically using a laparoscope with a fluorescent filter.

CONCLUSIONS

NV1066 has oncolytic activity against the BE3 cell line and may be a useful therapy against esophageal cancer. EGFP expression localizes the virus and may help to identify tumor deposits in vivo. Oncolytic activity with NV1066 against gastrointestinal cancers may potentially be tracked by endoscopy.