Preoperative Chemo-Radiation-Induced Ulceration in Patients with Esophageal Cancer: A Confounding Factor in Tumor Response Assessment in Integrated Computed Tomographic-Positron Emission Tomographic Imaging:

The MRI radiomics signature can predict the pathologic response to neoadjuvant chemotherapy in locally advanced esophageal squamous cell carcinoma

OBJECTIVES

To investigate the MRI radiomics signatures in predicting pathologic response among patients with locally advanced esophageal squamous cell carcinoma (ESCC), who received neoadjuvant chemotherapy (NACT).

METHODS

Patients who underwent NACT from March 2015 to October 2019 were prospectively included. Each patient underwent esophageal MR scanning within one week before NACT and within 2-3 weeks after completion of NACT, prior to surgery. Radiomics features extracted from T2-TSE-BLADE were randomly split into the training and validation sets at a ratio of 7:3. According to the progressive tumor regression grade (TRG), patients were stratified into two groups: good responders (GR, TRG 0 + 1) and poor responders (non-GR, TRG 2 + 3). We constructed the Pre/Post-NACT model (Pre/Post-model) and the Delta-NACT model (Delta-model). Kruskal-Wallis was used to select features, logistic regression was used to develop the final model.

RESULTS

A total of 108 ESCC patients were included, and 3/2/4 out of 107 radiomics features were selected for constructing the Pre/Post/Delta-model, respectively. The selected radiomics features were statistically different between GR and non-GR groups. The highest area under the curve (AUC) was for the Delta-model, which reached 0.851 in the training set and 0.831 in the validation set. Among the three models, Pre-model showed the poorest performance in the training and validation sets (AUC, 0.466 and 0.596), and the Post-model showed better performance than the Pre-model in the training and validation sets (AUC, 0.753 and 0.781).

CONCLUSIONS

MRI-based radiomics models can predict the pathological response after NACT in ESCC patients, with the Delta-model exhibiting optimal predictive efficacy.

CLINICAL RELEVANCE STATEMENT

MRI radiomics features could be used as a useful tool for predicting the efficacy of neoadjuvant chemotherapy in esophageal carcinoma patients, especially in selecting responders among those patients who may be candidates to benefit from neoadjuvant chemotherapy.

KEY POINTS

• The MRI radiomics features based on T2WI-TSE-BLADE could potentially predict the pathologic response to NACT among ESCC patients. • The Delta-model exhibited the best predictive ability for pathologic response, followed by the Post-model, which similarly had better predictive ability, while the Pre-model performed less well in predicting TRG.

Low metabolic activity in primary gastric adenocarcinoma is associated with resistance to chemoradiation and the presence of signet ring cells

PURPOSES

Preoperative chemoradiation is a potential treatment option for localized gastric adenocarcinoma (GAC). Currently, the response to chemoradiation cannot be predicted. We analyzed the pretreatment maximum standardized uptake value (SUV_max) and total lesion glycolysis (TLG) on positron emission tomography/computed tomography as potential predictors of the response to chemoradiation.

METHODS

We analyzed the SUV_max and TLG data from 59 GAC patients who received preoperative chemoradiation. We used logistic regression models to predict a pathologic complete response (pCR) and Kaplan-Meier curves to determine overall survival among patients with high and low SUV_max or TLG.

RESULTS

Twenty-nine patients (49%) had Siewert type III adenocarcinoma and 30 (51%) had tumors located in the lower stomach. Forty-one patients had poorly differentiated GAC, and 26 had signet ring cells. The median SUV_max was 7.3 (0-28.2) and the median TLG was 56.6 (0-1881.5). Patients with signet ring cells had a low pCR rate, as well as a low SUV_max and TLG. In the multivariable logistic regression model, high SUV_max was a predictor of pCR (odds ratio = 11.1, 95% confidence interval = 2.12-50.0, p = 0.004). Overall survival was not associated with the SUV_max (log-rank p = 0.69) or TLG (log-rank p = 0.85) CONCLUSION: A high SUV_max was associated with sensitivity to chemoradiation and pCR in GAC, and signet ring cells seemed to confer resistance.

Detecting Pathological Complete Response in Esophageal Cancer after Neoadjuvant Therapy Based on Imaging Techniques: A Diagnostic Systematic Review and Meta-Analysis

INTRODUCTION

Up to 32% of patients with esophageal cancer show a pathological complete response (ypCR) after neoadjuvant therapy. To prevent overtreatment, the indication to perform esophagectomy in these patients should be reconsidered. Implementing an organ-preserving strategy for patients with ypCR requires an accurate assessment of residual disease after neoadjuvant treatment. The aim of this study was to systematically review the effectiveness of imaging techniques used for detection of ypCR after neoadjuvant therapy but before resection in patients with esophageal cancer.

METHODS

A systematic literature search of the Medline, Embase, and Cochrane Library databases was performed from January 1, 2000, to December 13, 2017. Eligible studies were diagnostic studies that compared results of imaging modalities after neoadjuvant therapy to histopathological findings in the resection specimen after esophagectomy. Methodological quality was assessed by the Cochrane Quality Assessment of Diagnostic Accuracy Studies, version 2, model. Primary outcome measures were true positive, false-positive, false-negative, and true negative values of imaging techniques predicting ypCR. A meta-analysis was performed by pooling sensitivities and specificities by using a bivariate model.

RESULTS

A total of 4420 articles were identified. After exclusion of irrelevant titles and abstracts, 360 articles were reviewed in full text. In total, four imaging modalities (computed tomography [CT], positron emission tomography [PET-CT], endoscopic ultrasound [EUS], and magnetic resonance imaging [MRI]) were used for restaging. The meta-analysis was conducted with data from 56 studies involving 3625 patients. The pooled sensitivities of CT, PET-CT, EUS, and MRI for detecting ypCR were 0.35, 0.62, 0.01 and 0.80, respectively, whereas the pooled specificities were 0.83, 0.73, 0.99, and 0.83, respectively. The positive predictive value in detecting ypCR was 0.47 for CT, 0.41 for PET-CT, not applicable for EUS, and 0.61 for MRI.

CONCLUSION

Current imaging modalities such as CT, PET-CT, and EUS seem to be insufficiently accurate to identify complete responders. More accurate diagnostic tests are needed to improve restaging accuracy for patients with esophageal cancer.

Metabolic parameters of sequential 18F-FDG PET/CT predict overall survival of esophageal cancer patients treated with (chemo-) radiation

BACKGROUND

To evaluate the prognostic value of metabolic parameters of pre-treatment and interim 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) for overall survival (OS) of esophageal cancer(EC) patients undergoing (chemo-) radiotherapy.

METHODS

A retrospective analysis of 134 patients with pathology confirmed squamous cell EC treated between July 2009 and October 2013 in our hospital was performed. Inclusion criteria for this study were curative intended radiotherapy and availability of pre-treatment and interim 18F-FDG PET. 18F-FDG PET/CT scans were acquired before treatment and after 40 Gray (Gy) of radiotherapy. Maximum standard uptake value (SUV_max), metabolic tumor volume(MTV), total lesion glycolysis (TLG), and the percentual changes during both PET scans were recorded. The parameters were named as SUVmax1,MTV1,TLG1,SUVmax2,MTV2,TLG2,△SUV_max,△MTV and △TLG. The receiver operating characteristic curve (ROC) was used to analyze the relationship between metabolic parameters and OS, survival analysis was carried out by Kaplan-Meier and Cox regression analysis.

RESULTS

Univariate survival analysis showed that SUVmax2、MTV1、△MTV、TLG1、TLG2 and △TLG were associated with OS. Based on the largest Youden index of ROC curves, patients with SUVmax2 < 7.8, MTV1 < 10.5, △MTV < 0.075, TLG1 < 59.8, TLG2 < 44.3 and △TLG < 0.27 tended to live longer. Stratified for these parameters, the estimated median survival time were 27.9 months (m) vs 9.8 m, 36.9 m vs 11.3 m, 41.6 m vs 12 m, 48.9 m vs 14.3 m, 32.6 m vs 13.2 m, and 41.6 m vs 14.5 m. Cox multi-factor regression analyses revealed SUV_max2 as an independent prognostic factor for OS complementary to TNM staging and the length of primary tumor.

CONCLUSIONS

Sequential 18F-FDG PET/CT metabolic parameters bear important prognostic value for OS of EC patients. 18F-FDG PET/CT scan before treatment and during chemoradiotherapy seems helpful to evaluate the effect of chemoradiotherapy, guide clinical decisions and provide patients with personalized treatment.

Detection of distant interval metastases after neoadjuvant therapy for esophageal cancer with 18F-FDG PET(/CT): a systematic review and meta-analysis

Restaging after neoadjuvant therapy aims to reduce the number of patients undergoing esophagectomy in case of distant (interval) metastases. The aim of this study is to systematically review and meta-analyze the diagnostic performance of 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) and 18F-FDG PET/CT for the detection of distant interval metastases after neoadjuvant therapy in patients with esophageal cancer. PubMed/MEDLINE, Embase, and the Cochrane library were systematically searched. The analysis included diagnostic studies reporting on the detection of distant interval metastases with 18F-FDG PET(/CT) in patients with esophageal cancer who received neoadjuvant therapy and both baseline staging and restaging after neoadjuvant therapy with 18F-FDG PET(/CT) imaging. The primary outcome measure was the proportion of patients in whom distant interval metastases were detected by 18F-FDG PET(/CT) as confirmed by pathology or clinical follow-up (i.e. true positives). The secondary outcome measure was the proportion of patients in whom 18F-FDG PET(/CT) restaging was false positive for distant interval metastases (i.e. false positives). Risk of bias and applicability concerns were assessed using the QUADAS-2 tool. Random-effect models were used to estimate pooled outcomes and examine potential sources of heterogeneity. Fourteen studies were included comprising a total of 1,110 patients who received baseline staging with 18F-FDG PET(/CT) imaging of whom 1,001 (90%) underwent restaging with 18F-FDG PET(/CT) imaging. Studies were generally of moderate quality. The pooled proportion of patients in whom true distant interval metastases were detected by 18F-FDG PET(/CT) restaging was 8% (95% confidence interval [CI]: 5-13%). The pooled proportion of patients in whom false positive distant findings were detected by 18F-FDG PET(/CT) restaging was 5% (95% CI: 3-9%). In conclusion,18F-FDG PET(/CT) restaging after neoadjuvant therapy for esophageal cancer detects true distant interval metastases in 8% of patients. Therefore, 18F-FDG PET(/CT) restaging can considerably impact on treatment decision-making. However, false positive distant findings occur in 5% of patients at restaging with 18F-FDG PET(/CT), underlining the need for pathological confirmation of suspected lesions.

[Importance of PET in surgery of esophageal cancer]

Perioperative or preoperative radiochemotherapy (RCTx) is nowadays standard for locally advanced esophageal cancer in Europe, as randomized studies have shown a significant survival benefit for patients with multimodal treatment. As responders and nonresponders have a significantly different prognosis, a response-based tailored preoperative treatment would be of utmost interest. An established method is a metabolic response evaluation by 18F-fluorodeoxyglucose positron emission tomography (FDG-PET). The level of metabolic response is known to be dependent on the localization, tumor entity and type of preoperative treatment. Association of FDG-PET with later response and prognosis was shown for absolute standardized uptake values (SUV) or a decrease of SUV levels before and after therapy but there are also contradictory findings in the literature and no prospective validation. However, neither time points nor cut-off for metabolic response evaluation have been defined so far. The most interesting approach seems to be early response monitoring during preoperative chemotherapy, which has shown promising results in prospective single center trials (MUNICON I/II) during chemotherapy of adenocarcinoma of the esophagogastric junction (AEG), but needs to be validated in prospective multicenter trails.

(18)F-FDG-PET/CT in assessing response to neoadjuvant chemoradiotherapy for potentially resectable locally advanced esophageal cancer

PURPOSE

To correlate metabolic response to neoadjuvant chemoradiotherapy (NACR) on FDG-PET/CT using PERCIST-based criteria to pathologic and clinical response, and survival in patients with locally advanced esophageal cancer (LAEC).

MATERIALS AND METHODS

Forty-five patients with LAEC underwent PET/CT at baseline and after NACR. Tumors were evaluated using PERCIST (PET response criteria in solid tumors)-based criteria including SUL, SUL tumor/liver ratio, % change in SUL. These parameters were compared to pathology regression grade (PRG), clinical response (including residual or new disease beyond the surgical specimen), and overall survival.

RESULTS

On surgical pathology, there was complete or near-complete regression of tumor in 51.1 %, partial response in 42.2 %, and lack regression in 4.4 %. One patient (2.2 %) had progression of disease on imaging and did not undergo surgical resection. None of the baseline PET parameters had significant correlation to pathology regression grade or clinical response. On follow-up, a positive correlation was found between post-therapy SUL ratio, %∆ SUL and %∆ SUL ratio and clinical response (p = 0.025, 0.035, 0.030, respectively). A weak correlation was found between post-therapy SUL ratio to PRG (p = 0.049). A strong correlation was found between the metabolic response score and PRG (p = 0.002) as well as between metabolic response and clinical response (p < 0.001).

CONCLUSION

PERCIST-based metabolic response assessment to NACR in LAEC may correlate with clinical outcome and survival.

Esophagectomy after chemoradiation: who and when to operate

Neoadjuvant chemoradiation is the standard of care for locally advanced esophageal cancer. After completion of chemoradiotherapy, deciding which patients benefit from surgery remains a challenge. For patients who decide on surgery, the optimal timing is unknown. The complexity of these questions requires an individualized approach, taking into account the expertise of the surgeon, the condition of the patient, and the biology of the tumor.

Metabolic response at repeat PET/CT predicts pathological response to neoadjuvant chemotherapy in oesophageal cancer

OBJECTIVES

Reports have suggested that a reduction in tumour 18F-fluorodeoxyglucose (FDG) uptake on positron emission tomography (PET) examination during or after neoadjuvant chemotherapy may predict pathological response in oesophageal cancer. Our aim was to determine whether metabolic response predicts pathological response to a standardised neoadjuvant chemotherapy regimen within a prospective clinical trial.

METHODS

Consecutive patients staged with potentially curable oesophageal cancer who underwent treatment within a non-randomised clinical trial were included. A standardised chemotherapy regimen (two cycles of oxaliplatin and 5-fluorouracil) was used. PET/CT was performed before chemotherapy and repeated 24-28 days after the start of cycle 2.

RESULTS

Forty-eight subjects were included: mean age 65 years; 37 male. Using the median percentage reduction in SUV(max) (42%) to define metabolic response, pathological response was seen in 71% of metabolic responders (17/24) compared with 33% of non-responders (8/24; P = 0.009, sensitivity 68%, specificity 70%). Pathological response was seen in 81% of subjects with a complete metabolic response (13/16) compared with 38% of those with a less than complete response (12/32; P = 0.0042, sensitivity 52%, specificity 87%). There was no significant histology-based effect.

CONCLUSIONS

There was a significant association between metabolic response and pathological response; however, accuracy in predicting pathological response was relatively low.

Barrett's esophagus: treatments of adenocarcinomas II

The following topics are explored in this collection of commentaries on treatments of adenocarcinomas related to Barrett's esophagus: the importance of intraoperative frozen sections of the margins for the detection of high dysplasia; the preferable way for sentinel node dissection; the current role of robotic surgery and of video-endoscopic approach; the value of the Siewert's classification of adenocarcinomas; the indications of two-step esophagectomy; the evaluation of pathological complete response; the role of PET scan in staging and response assessment; the role of p53 in the selection of adenocarcinomas patients; chemotherapy regimens for adenocarcinomas; the use of monoclonal antibodies in the control of cell proliferation; he attempt to define a stage-specific strategy, and the possible indications of selective therapy; and changes in mortality rates from esophageal cancer.

A Phase II study of a paclitaxel-based chemoradiation regimen with selective surgical salvage for resectable locoregionally advanced esophageal cancer: initial reporting of RTOG 0246

PURPOSE

The strategy of definitive chemoradiation with selective surgical salvage in locoregionally advanced esophageal cancer was evaluated in a Phase II trial in Radiation Therapy Oncology Group (RTOG)-affiliated sites.

METHODS AND MATERIALS

The study was designed to detect an improvement in 1-year survival from 60% to 77.5% (α = 0.05; power = 80%). Definitive chemoradiation involved induction chemotherapy with 5-fluorouracil (5-FU) (650 mg/mg(2)/day), cisplatin (15 mg/mg(2)/day), and paclitaxel (200 mg/mg(2)/day) for two cycles, followed by concurrent chemoradiation with 50.4 Gy (1.8 Gy/fraction) and daily 5-FU (300 mg/mg(2)/day) with cisplatin (15 mg/mg(2)/day) over the first 5 days. Salvage surgical resection was considered for patients with residual or recurrent esophageal cancer who did not have systemic disease.

RESULTS

Forty-three patients with nonmetastatic resectable esophageal cancer were entered from Sept 2003 to March 2006. Forty-one patients were eligible for analysis. Clinical stage was ≥T3 in 31 patients (76%) and N1 in 29 patients (71%), with adenocarcinoma histology in 30 patients (73%). Thirty-seven patients (90%) completed induction chemotherapy followed by concurrent chemoradiation. Twenty-eight patients (68%) experienced Grade 3+ nonhematologic toxicity. Four treatment-related deaths were noted. Twenty-one patients underwent surgery following definitive chemoradiation because of residual (17 patients) or recurrent (3 patients) esophageal cancer,and 1 patient because of choice. Median follow-up of live patients was 22 months, with an estimated 1-year survival of 71%.

CONCLUSIONS

In this Phase II trial (RTOG 0246) evaluating selective surgical salvage after definitive chemoradiation in locoregionally advanced esophageal cancer, the hypothesized 1-year RTOG survival rate (77.5%) was not achieved (1 year, 71%; 95% confidence interval< 54%-82%).

Intratumor heterogeneity characterized by textural features on baseline 18F-FDG PET images predicts response to concomitant radiochemotherapy in esophageal cancer

(18)F-FDG PET is often used in clinical routine for diagnosis, staging, and response to therapy assessment or prediction. The standardized uptake value (SUV) in the primary or regional area is the most common quantitative measurement derived from PET images used for those purposes. The aim of this study was to propose and evaluate new parameters obtained by textural analysis of baseline PET scans for the prediction of therapy response in esophageal cancer.

METHODS

Forty-one patients with newly diagnosed esophageal cancer treated with combined radiochemotherapy were included in this study. All patients underwent pretreatment whole-body (18)F-FDG PET. Patients were treated with radiotherapy and alkylatinlike agents (5-fluorouracil-cisplatin or 5-fluorouracil-carboplatin). Patients were classified as nonresponders (progressive or stable disease), partial responders, or complete responders according to the Response Evaluation Criteria in Solid Tumors. Different image-derived indices obtained from the pretreatment PET tumor images were considered. These included usual indices such as maximum SUV, peak SUV, and mean SUV and a total of 38 features (such as entropy, size, and magnitude of local and global heterogeneous and homogeneous tumor regions) extracted from the 5 different textures considered. The capacity of each parameter to classify patients with respect to response to therapy was assessed using the Kruskal-Wallis test (P < 0.05). Specificity and sensitivity (including 95% confidence intervals) for each of the studied parameters were derived using receiver-operating-characteristic curves.

RESULTS

Relationships between pairs of voxels, characterizing local tumor metabolic nonuniformities, were able to significantly differentiate all 3 patient groups (P < 0.0006). Regional measures of tumor characteristics, such as size of nonuniform metabolic regions and corresponding intensity nonuniformities within these regions, were also significant factors for prediction of response to therapy (P = 0.0002). Receiver-operating-characteristic curve analysis showed that tumor textural analysis can provide nonresponder, partial-responder, and complete-responder patient identification with higher sensitivity (76%-92%) than any SUV measurement.

CONCLUSION

Textural features of tumor metabolic distribution extracted from baseline (18)F-FDG PET images allow for the best stratification of esophageal carcinoma patients in the context of therapy-response prediction.

Critical role of surgery in patients with gastroesophageal carcinoma with a poor prognosis after chemoradiation as defined by positron emission tomography

BACKGROUND

The prognosis of patients with localized gastroesophageal carcinoma (LGC) can be defined after chemoradiation by the standardized uptake value (SUV) of positron emission tomography (PET). High SUV (HSUV) after chemoradiation portends a poor prognosis. The authors retrospectively examined the role of surgery in patients with HSUV after chemoradiation.

METHODS

The authors analyzed the postchemoradiation PET scans of 204 LGC patients. One hundred twenty-nine patients had HSUV. Two postchemoradiation variables were evaluated: SUV and surgery and their association with overall survival (OS) and event-free survival (EFS). The log-rank test, multivariate Cox proportional hazards model, and Kaplan-Meier survival plots were used to assess the association between OS or EFS and the dichotomized SUV (using the median SUV as the cutoff) and surgery.

RESULTS

The median SUV was 4.6. The OS of the 52 patients who had an SUV above the median and did not undergo surgery (HSUV-NS) (median OS, 1.22 years; 95% confidence interval [95% CI], 1.02-2.16 years) was much shorter than that of the 77 patients with an SUV above the median who underwent surgery (HSUV-S) (median OS, 2.7 years; 95% CI, 2.43 years to not reached [P<.0001]). Similarly, the EFS for patients with HSUV-NS was significantly shorter than that for patients with HSUV-S (P=.001). In the multivariate analyses, patients who underwent surgery (irrespective of SUV) had a lower risk of death (P=.0001) and disease progression (P=.002).

CONCLUSIONS

The data from the current study suggest that surgery may prolong OS and EFS in patients with a poor prognosis after chemoradiation as defined by PET. However, these data need confirmation.

Prediction of tumor response to neoadjuvant therapy in patients with esophageal cancer with use of 18F FDG PET: a systematic review

PURPOSE

To systematically review the accuracy of fluorine 18 ((18)F) fluorodeoxyglucose (FDG) positron emission tomography (PET) in the prediction of tumor response to neoadjuvant therapy in patients with esophageal cancer.

MATERIALS AND METHODS

The MEDLINE and EMBASE databases were systematically searched for relevant studies. Methodologic quality of the included studies was assessed. Sensitivities and specificities of (18)F FDG PET in individual studies were calculated and underwent meta-analysis with a random effects model. A summary receiver operating characteristic curve (sROC) was constructed with the Moses-Shapiro-Littenberg method. A chi(2) test was performed to test for heterogeneity (defined as P < .10). Potential sources for heterogeneity were explored by assessing whether certain covariates significantly (P < .05) influenced the relative diagnostic odds ratio.

RESULTS

Twenty reports, comprising a total of 849 patients with esophageal cancer, were included. Overall, the studies were of moderate methodologic quality. Sensitivity and specificity of (18)F FDG PET ranged from 33% to 100% and from 30% to 100%, respectively, with pooled estimates of 67% (95% confidence interval: 62%, 72%) and 68% (95% confidence interval: 64%, 73%), respectively. The area under the sROC curve was 0.7815. There was significant heterogeneity in both the sensitivity and specificity of the included studies (P < .0001). Spearman rho between the logit of sensitivity and the logit of 1-specificity was 0.086 (P = .719), which suggested that there was no threshold effect. Studies performed outside of the United States and studies of higher methodologic quality yielded significantly higher overall accuracy.

CONCLUSION

On the basis of current evidence, (18)F FDG PET should not yet be used in routine clinical practice to guide neoadjuvant therapy decisions in patients with esophageal cancer.

SUPPLEMENTAL MATERIAL

http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.09091324/-/DC1.

Positron emission tomography’s changing significance in the treatment of esophageal cancer

Incidence of esophageal cancer has been rising, and Positron Emission Tomography (PET) is one tool that has shown utility and promise as a tool for staging, treatment response, and prognosis. PET delivery has evolved over time and is now frequently registered with a CT scan at the time of acquisition. However, resolution and confounders such as post-treatment radiation changes may limit clinical utility. PET has been shown to be helpful in staging, especially in evaluating for distant metastases. PET acquired after chemoradiation may give important prognostic information that can guide additional treatment decisions. Studies have had substantial variability in recommendations for the timing and manner of using PET for this purpose, and additional study is needed.

Multimodality assessment of esophageal cancer: preoperative staging and monitoring of response to therapy

Esophageal cancer is a leading cause of cancer mortality worldwide. Complete resection of esophageal cancer and adjacent malignant lymph nodes is the only potentially curative treatment. Accurate preoperative staging and assessment of therapeutic response after neoadjuvant therapy are crucial in determining the most suitable therapy and avoiding inappropriate attempts at curative surgery. Computed tomography (CT) is recommended for initial imaging following confirmation of malignancy at pathologic analysis, primarily to rule out unresectable or distant metastatic disease. With the advent of multidetector CT, use of thin sections and multiplanar reformation allows more accurate staging of esophageal cancer. Endoscopic ultrasonography (US) is the best modality for determining the depth of tumor invasion and presence of regional lymph node involvement. Combined use of fine-needle aspiration and endoscopic US can improve assessment of lymph node involvement. Positron emission tomography (PET) is useful for assessment of distant metastases but is not appropriate for detecting and staging primary tumors. PET may also be helpful in restaging after neoadjuvant therapy, since it allows identification of early response to treatment and detection of interval distant metastases. Each imaging modality has its advantages and disadvantages; therefore, CT, endoscopic US, and PET should be considered complementary modalities for preoperative staging and therapeutic monitoring of patients with esophageal cancer.

Evidence-based radiation oncology: oesophagus

Oesophageal cancer remains to be a therapeutic and diagnostic challenge in multidisciplinary oncology. Radiotherapy is a crucial component of most curative and palliative approaches for oesophageal cancer. Aim of this educational review is to summarize the available evidence and to define the role of radiation-based treatment options for oesophageal cancer.

Future developments in esophageal cancer research

The progress that has been made against esophageal carcinoma is limited. Many relevant issues remain. Herein the author discusses his outlook for the treatment of this disease, which has a steadily rising incidence.

The role of FDG-PET and staging laparoscopy in the management of patients with cancer of the esophagus or gastroesophageal junction

The effort to improve outcomes in esophageal cancer has included attempts at improving staging and patient selection. 2-Deoxy-2-[(18)F]fluoro-Dglucose positron emission tomography (FDG-PET) has been extensively studied in this context and has been widely accepted as a staging tool. Its role in restaging or assessing therapeutic response is investigational and promising. Laparoscopy has also been studied as a means for improving staging, but its role may be limited in the era of PET. This article discusses the literature assessing these modalities, particularly with regard to the practical management of the patient in the clinic.

Tumor biology-guided radiotherapy treatment planning: gross tumor volume versus functional tumor volume

This issue of Seminars in Nuclear Medicine deals with a watershed event in cancer treatment -- the combined use of functional and anatomical information to guide therapeutic interventions. The use of positron emission tomography/computed tomography (PET/CT) in radiation treatment planning and tumor response evaluation brings a paradigm change in the development of image-guided therapies into routine clinical practice. The implications, as seen in the following articles, are not only promising but also groundbreaking. And, as in every new scientific breakthrough, each step forward generates a myriad of additional important clinical and research questions. Functional imaging takes advantage of the subtle differences between normal and malignant tissues at the cellular level to reveal in vivo unique functional characteristics of neoplasms. The ultimate goal of the partnership between nuclear medicine physicians and radiation oncologists is to use this information with absolute clarity in target definition for radiation treatment planning and therapy, as well as response evaluation. Functional imaging can provide metabolic information and behavioral correlation along with the anatomical imaging for correlative target delineation. Additionally, as a purely diagnostic instrument, PET/CT provides a tool for oncologists to make critical decisions regarding radiation treatment planning modifications secondary to changes in tumor staging (up or down), treatment field modifications, localized control, sites of residual and/or metastatic disease and post therapy response evaluation. The articles in this issue of the seminars provide insights into the current state-of-the-art of functional imaging techniques, mostly centered on the use of (18)F-fluorodeoxyglucose PET/CT in image guided oncologic therapies. Because it is a novel science, the future of image-guided functional treatment planning is bright with technologic and biologic innovations, translational research and new clinical applications.

PET/CT of esophageal cancer: its role in clinical management

Positron emission tomography (PET)/computed tomography (CT) has important utility and limitations in the initial staging of esophageal cancer, evaluation of response to neoadjuvant therapy, and detection of recurrent malignancy. Esophageal cancer is often treated by using a combined modality approach (chemotherapy, radiation therapy, and esophagectomy); correct integration of PET/CT into the conventional work-up of esophageal cancer requires a multidisciplinary approach that combines the information from PET/CT with results of clinical assessment, diagnostic CT, endoscopic gastroduodenoscopy, and endoscopic ultrasonography. PET/CT has limited utility in T staging of esophageal cancer and relatively limited utility in detection of dissemination to locoregional lymph nodes. However, PET/CT allows detection of metastatic disease that may not be identifiable with other methods. PET/CT is not sufficiently reliable in the individual patient for determination of treatment response in the primary tumor. Interpretation of PET/CT results is optimized by understanding the diagnostic limitations and pitfalls that may be encountered, together with knowledge of the natural history of esophageal cancer and the staging and treatment options available.

FDG-PET Evaluation of Response to Treatment

This article discusses evaluating response after and during therapy in various settings and for the types of cancers for which ample evidence demonstrates that PET imaging with flourodeoxyglucose provides a valuable surrogate for response to therapy. It also briefly discusses pitfalls in obtaining an optimal assessment of response and issues that need further attention for this modality to become established as an independent predictor of response to anticancer therapy.

Detection of interval distant metastases

BACKGROUND

The objective of the study was to determine the utility of integrated computed tomography / positron emission tomography (CT-PET) imaging for detecting interval distant metastases and assessing therapeutic response in patients with locally advanced, potentially resectable esophageal carcinoma after neoadjuvant therapy.

METHODS

A retrospective study was performed of 88 patients with potentially resectable esophageal carcinoma who received neoadjuvant therapy before planned surgical resection. CT-PET before and after completion of neoadjuvant was used for evaluating therapeutic response; response criteria were based on qualitative and semiquantitative analyses.

RESULTS

Neoadjuvant therapy comprised chemoradiotherapy in 85 patients, with prior induction chemotherapy in 39 patients. Fifty-five patients proceeded to esophagectomy. Repeat CT-PET was performed after induction chemotherapy (n = 23) and after completing chemoradiotherapy (n = 85). CT-PET identified the interval appearance of metastatic disease in 7 (8%) patients. For assessment of locoregional therapeutic response, CT-PET was unable to predict pathological response to neoadjuvant therapy in the primary tumor or locoregional lymph nodes. CT-PET had sensitivity, specificity, and positive and negative predictive values of 57%, 46%, 39%, and 64%, respectively, for detection of residual macroscopic malignancy within the primary tumor; and sensitivity, specificity, and positive and negative predictive values of 0%, 90%, 0%, and 69% for detection of residual malignancy within resected lymph nodes.

CONCLUSIONS

CT-PET performed after neoadjuvant therapy in patients with potentially resectable esophageal carcinoma is important for detecting interval metastases that preclude surgical resection, but is of limited utility for assessing locoregional therapeutic response.