Positron emission tomography and pathological evidence of response to neoadjuvant therapy in adenocarcinoma of the esophagus

False Liver Metastasis by Positron Emission Tomography/Computed Tomography Scan after Chemoradiotherapy for Esophageal Cancer-Potential Overstaged Pitfalls of Treatment

In patients with esophageal cancer undergoing neoadjuvant chemoradiotherapy (nCRT), subsequent restaging with F-18-fluorodeoxyglucose (18F-FDG) positron emission tomography-computed tomography (PET-CT) can reveal the presence of interval metastases, such as liver metastases, in approximately 10% of cases. Nevertheless, it is not uncommon in clinical practice to observe focal FDG uptake in the liver that is not associated with liver metastases but rather with radiation-induced liver injury (RILI), which can result in the overstaging of the disease. Liver radiation damage is also a concern during distal esophageal cancer radiotherapy due to its proximity to the left liver lobe, typically included in the radiation field. Post-CRT, if FDG activity appears in the left or caudate liver lobes, a thorough investigation is needed to confirm or rule out distant metastases. The increased FDG uptake in liver lobes post-CRT often presents a diagnostic dilemma. Distinguishing between radiation-induced liver disease and metastasis is vital for appropriate patient management, necessitating a combination of imaging techniques and an understanding of the factors influencing the radiation response. Diagnosis involves identifying new foci of hepatic FDG avidity on PET/CT scans. Geographic regions of hypoattenuation on CT and well-demarcated regions with specific enhancement patterns on contrast-enhanced CT scans and MRI are characteristic of radiation-induced liver disease (RILD). Lack of mass effect on all three modalities (CT, MRI, PET) indicates RILD. Resolution of abnormalities on subsequent examinations also helps in diagnosing RILD. Moreover, it can also help to rule out occult metastases, thereby excluding those patients from further surgery who will not benefit from esophagectomy with curative intent.

Treatment Response to Neoadjuvant Therapy in Squamous Esophageal Cancer-Correlation Between Metabolic Response and Histopathology

PURPOSE

Esophageal cancer is among the leading causes of cancer-related mortality worldwide. Patients presenting with localized and loco-regionally advanced cancer without distant metastases have reasonable survival with multimodality management. Adequate and comprehensive staging is the backbone for proper selection of patients fit for curative treatment. Positron emission tomography (PET) in combination with contrast-enhanced computed tomography (CECT) is utilized as the standard staging modality. Multimodality treatment has been able to achieve evaluable tumor responses including pathological complete response (pCR). It is, therefore, necessary to understand whether the impact of neoadjuvant therapy can be evaluated on imaging, i.e., standardized uptake value (SUV) on PET scan done for response assessment and if this can be correlated with histopathological response and later, with survival. Squamous cell carcinoma (SCC) is more common globally and in the Indian subcontinent; hence, we chose this subgroup to evaluate our hypothesis.

METHODS

This is a single institution, retrospective study. Out of the 1967 patients who were treated between 2009 and 2019, 1369 (78.54%) patients had SCC. Out of these, 44 received NACTRT, whereas 1325 received NACT followed by curative surgery. The standardized uptake value (SUV) of 18-fluorodeoxyglucose was recorded during pre- and post-neoadjuvant treatment (NAT) using positron emission tomography (PET). The histopathology of the final resection specimen was evaluated using the Mandard tumor regression grade (TRG) criteria with response being graded from 0 to 5 as no residual tumor (NRT), scanty residual tumor (SRT), and residual tumor We attempted to find a cut-off value of the post neoadjuvant SUV of the primary tumor site which correlated with achievement of better histopathological response.

RESULTS

Out of 1325 patients of SCC esophagus who underwent surgery, 943 patients had available data of TRG, and it was categorized into the 0-2 category which had 325 patients (34.5%) and 3-5 category, 618 patients (65.5%). The SUV was taken only from the PET scans done at our institution, so as to achieve a more homogenous cohort, and this was available for 186 patients, 151 from the NACT group and 35 from the NACTRT group. The ROC method was used to find the cut-off for SUV (5.05) in the NACT cohort, which depicted significant difference in the outcome. Out of these, 93 patients who underwent NACT had SUV > 5.05 and 58 had SUV < 5.05. It was found that the subjective and objective histopathological scores correlated at a p value of < 0.0001. Specifically, the majority of cases with SRT tended to be in the 3-5 category of TRG, whereas cases with NRT are predominantly in the 0-2 category. In the ≥ 5.05 category of SUV, there were 76 cases with SRT. In the NACT cohort, the < 5.05 category of SUV, there are 26 cases with SRT and 32 cases with NRT. Among cases with SRT, 74.5% had SUV ≥ 5.05, while 25.5% had SUV < 5.05. Among cases with NRT, 34.7% had SUV ≥ 5.05, while 65.3% had SUV < 5.05 (p value 0.007). No significant association was found in the radio-pathological correlation in the NACTRT group.

CONCLUSION

Our study confirms the correlation of post neoadjuvant chemotherapy PET SUV with histopathological response, the cut-off of SUV being 5.05 in our cohort. This confirms the predictive value of FDG PET as demonstrated in other studies. Furthermore, its prognostic value with respect to survival has been verified in multiple other studies. With larger scale randomized studies, we may be able to identify the group of patients who have borderline operability anatomically as well as physiologically, where alternative treatment regimens may be indicated to improve outcomes.

Role of (F-18) Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in the Prediction of Response to Neoadjuvant Therapy in Esophageal Cancer: Correlation with Pathological Response and Survival

Purpose

The purpose of this study is to assess the correlation between metabolic response with fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) and pathological response in patients with locally advanced esophageal cancer treated with neoadjuvant chemoradiotherapy and to study FDG-PET parameters for the prediction of pathological response and outcome.

Methods

Twenty-five patients with locally advanced esophageal cancer underwent two FDG-PET/CT scans for initial staging and after neoadjuvant chemoradiotherapy. FDG uptake in the primary tumor was calculated in both scans (SUVmax, SULpeak, and TLG). Metabolic response was assessed according to the reduction of PET parameters: complete response (mCR = 100%), partial response (mPR ≥50%), and no response (mNR ≤50%). Pathological response was also classified as complete (pCR), partial (pPR), or no response (pNR). Patients were followed up (range, 8-99 months) determining free-disease interval (FDI) and overall survival (OS).

Results

Two patients were excluded due to exitus for nonesophageal-related causes. The metabolic response was observed in 18/23 remaining patients (3mCR, 15 mPR), of which 12/18 patients showed a pathological response (3 pCR, 9 pPR). A major discrepancy was observed in 2 mNR patients who achieved pPR. FDI and OS were longer in patients with metabolic response than nonresponders, but no statistical difference was found. No significant correlation was found between PET parameters and pathological response, FDI, and OS.

Conclusions

FDG-PET/CT is a useful technique to assess response to neoadjuvant chemoradiotherapy in esophageal cancer. Although in this preliminary study, no correlation between metabolic and pathologic response was found and no statistical differences between responders and nonresponders were observed, a tendency of longer FDI and OS was apparently found in responders patients.

Maximum standardized uptake value change rate before and after neoadjuvant chemotherapy can predict early recurrence in patients with locally advanced esophageal cancer: a multi-institutional cohort study of 220 patients in Japan

BACKGROUND

Neoadjuvant chemotherapy (NAC) followed by esophagectomy can improve the prognosis of locally advanced esophageal cancer (LAEC). However, LAEC reportedly recurred in 17-21% of patients within 6 months post surgery. Thus, current treatment strategies may be inadequate for LAECs with poor prognosis. Preoperative identification of patients with poor prognosis might aid in modification of treatment strategies. This study aimed to evaluate the usefulness of the maximum standardized uptake value change rate (ΔSUV_max) in predicting treatment effects on the primary lesion, prognosis, and LAEC recurrence.

METHODS

This study involved 220 esophageal cancer patients who underwent esophagectomy after NAC at three facilities in Japan. The optimal cut-off point for ΔSUV_max in predicting tumor regression grade (TRG) was calculated and used to assess the correlation between ΔSUV_max and postoperative survival.

RESULTS

The optimal cut-off point for ΔSUV_max was 0.5. The 5-year overall survival rate in patients with ΔSUV_max ≥ 0.5 was significantly higher than that in patients with ΔSUV_max < 0.5 (71.5% vs. 50.5%, P = 0.001). Multivariate analysis identified ΔSUV_max (hazards ratio, 0.496; P = 0.004) as an independent prognostic factor. Among 199 patients evaluated for recurrence, 24 (12.1%) showed recurrence within 6 months post surgery. Univariate analysis revealed ΔSUV_max as the only predictor for early recurrence (odds ratio, 0.222; P = 0.004).

CONCLUSION

ΔSUV_max before and after NAC is clinically useful as it could help predict TRG, survival outcome, and early recurrence within 6 months post esophagectomy and is easily obtainable in general clinical practice. We believe that it may also help determine suitable treatment strategies for LAEC.

18F-FDG-PET/CT Imaging for Gastrointestinal Malignancies

Gastrointestinal malignancies encompass a variety of primary tumor sites, each with different staging criteria and treatment approaches. In this review we discuss technical aspects of 18F-FDG-PET/CT scanning to optimize information from both the PET and computed tomography components. Specific applications for 18F-FDG-PET/CT are summarized for initial staging and follow-up of the major disease sites, including esophagus, stomach, hepatobiliary system, pancreas, colon, rectum, and anus.

Accuracy of Detecting Residual Disease After Neoadjuvant Chemoradiotherapy for Esophageal Cancer: A Systematic Review and Meta-analysis

OBJECTIVE

The aim of this study was to perform a meta-analysis on the accuracy of endoscopic biopsies, EUS, and 18F-FDG PET(-CT) for detecting residual disease after neoadjuvant chemoradiotherapy (nCRT) for esophageal cancer.

SUMMARY OF BACKGROUND DATA

After nCRT, one-third of patients have a pathologically complete response in the resection specimen. Before an active surveillance strategy could be offered to these patients, clinically complete responders should be accurately identified.

METHODS

Embase, Medline, Cochrane, and Web-of-Science were searched until February 2018 for studies on accuracy of endoscopic biopsies, EUS, or PET(-CT) for detecting locoregional residual disease after nCRT for squamous cell- or adenocarcinoma. Pooled sensitivities and specificities were calculated using random-effect meta-analyses.

RESULTS

Forty-four studies were included for meta-analyses. For detecting residual disease at the primary tumor site, 12 studies evaluated endoscopic biopsies, 11 qualitative EUS, 14 qualitative PET, 8 quantitative PET using maximum standardized uptake value (SUVmax), and 7 quantitative PET using percentage reduction of SUVmax (%ΔSUVmax). Pooled sensitivities and specificities were 33% and 95% for endoscopic biopsies, 96% and 8% for qualitative EUS, 74% and 52% for qualitative PET, 69% and 72% for PET-SUVmax, and 73% and 63% for PET-%ΔSUVmax. For detecting residual nodal disease, 11 studies evaluated qualitative EUS with a pooled sensitivity and specificity of 68% and 57%, respectively. In subgroup analyses, sensitivity of PET-%ΔSUVmax and EUS for nodal disease was higher in squamous cell carcinoma than adenocarcinoma.

CONCLUSIONS

Current literature suggests insufficient accuracy of endoscopic biopsies, EUS, and 18F-FDG PET(-CT) as single modalities for detecting residual disease after nCRT for esophageal cancer.

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.

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.

Prediction and diagnosis of interval metastasis after neoadjuvant chemoradiotherapy for oesophageal cancer using 18F-FDG PET/CT

OBJECTIVE

During neoadjuvant chemoradiotherapy for oesophageal cancer, or in the interval prior to surgery, some patients develop systemic metastasis. This study aimed to evaluate the diagnostic performance of ¹⁸F-FDG PET/CT for the detection of interval metastasis and to identify predictors of interval metastases in a large cohort of oesophageal cancer patients.

METHODS

In total, 783 consecutive patients with potentially resectable oesophageal cancer who underwent chemoradiotherapy and pre- and post-treatment ¹⁸F-FDG PET/CT between 2006 and 2015 were analyzed from a prospectively maintained database. Diagnostic accuracy measures were calculated on a per-patient basis using histological verification or clinical follow-up as a reference standard. Multivariable logistic regression analysis was performed to determine pre-treatment predictors of interval metastasis. A prediction score was developed to predict the probability of interval metastasis.

RESULTS

Of 783 patients that underwent ¹⁸F-FDG PET/CT restaging, 65 (8.3%) were found to have interval metastasis and 44 (5.6%) were deemed to have false positive lesions. The resulting sensitivity and specificity was 74.7% (95% CI: 64.3-83.4%) and 93.7% (95% CI: 91.6-95.4%), respectively. Multivariable analysis revealed that tumor length, cN status, squamous cell tumor histology, and baseline SUV_max were associated with interval metastasis. Based on these criteria, a prediction score was developed with an optimism adjusted C-index of 0.67 that demonstrated accurate calibration.

CONCLUSIONS

¹⁸F-FDG PET/CT restaging detects distant interval metastases in 8.3% of patients after chemoradiotherapy for oesophageal cancer. The provided prediction score may stratify risk of developing interval metastasis, and could be used to prioritize additional restaging modalities for patients most likely to benefit.

The predictive value of 18F-FDG PET for pathological response of primary tumor in patients with esophageal cancer during or after neoadjuvant chemoradiotherapy: a meta-analysis

OBJECTIVE

We want to review the value of 18-fluoro-deoxy-glucose positron emission tomography for response prediction of primary tumor in patients with esophageal cancer during or after neoadjuvant chemoradiotherapy.

METHODS

Studies were searched in Pubmed, Embase and Cochrane Library with specific search strategy. The published articles were included according to the criteria established in advance. The included studies were divided into two groups according to the time of the repeat positron emission tomography: during (Group A) or after neoadjuvant chemoradiotherapy (Group B). The studies that performed the repeat positron emission tomography after neoadjuvant chemoradiotherapy were graded Quality Assessment of Diagnostic Accuracy Studies. The pooled sensitivity, specificity and diagnostic odds ratio were obtained for both groups on the basis of no-existing of threshold effect.

RESULTS

Fifteen studies were included in the present study. The threshold effect did not exist in both groups. The pooled sensitivity, specificity and diagnostic odds ratio were 85%, 59%, 6.82 with 95% confidence interval 76-91%, 48-69%, 2.25-20.72 in Group A. The equivalent values were 67%, 69%, 6.34 with 95% confidence interval 60-73%, 63-74%, 2.08-19.34 in Group B. The pooled sensitivity was 90% in four studies that enrolled patients with esophageal squamous cell carcinoma merely in Group B.

CONCLUSIONS

According to the present data, positron emission tomography should not be used routinely to guide treatment strategy in esophageal cancer patients. We speculated that positron emission tomography could be used as a tool to predict treatment response after neoadjuvant chemoradiotherapy in patients with esophageal squamous cell carcinoma.

Potentially Curable Cancers of the Esophagus and Stomach

Gastric and gastroesophageal adenocarcinomas continue to be a major health burden globally and collectively represent the third leading cause of cancer death. Among patients with metastatic disease, most die of their cancer because of the limited number of modestly effective treatment regimens available today. The progress against these cancers has been slow compared with many other solid tumors despite many attempts. In-depth molecular profiling has also not been completed. Even when these cancers are localized, they impose considerable challenges for the patient, relatives, and treatment team alike. Localized gastric or gastroesophageal cancer is best managed with a multidisciplinary approach. This review focuses on the management of localized cancers by reviewing the current literature and explaining certain principles that help guide therapy for these patients. The future, however, will afford numerous opportunities, including exploitation of initial data from The Cancer Genome Atlas, to identify novel targets and drugs, harness the prowess of the immune system, and customize therapy for each patient.

Relationship between the Temporal Changes in Positron-Emission-Tomography-Imaging-Based Textural Features and Pathologic Response and Survival in Esophageal Cancer Patients

PURPOSE

Although change in standardized uptake value (SUV) measures and PET-based textural features during treatment have shown promise in tumor response prediction, it is unclear which quantitative measure is the most predictive. We compared the relationship between PET-based features and pathologic response and overall survival with the SUV measures in esophageal cancer.

METHODS

Fifty-four esophageal cancer patients received PET/CT scans before and after chemoradiotherapy. Of these, 45 patients underwent surgery and were classified into complete, partial, and non-responders to the preoperative chemoradiation. SUVmax and SUVmean, two cooccurrence matrix (Entropy and Homogeneity), two run-length matrix (RLM) (high-gray-run emphasis and Short-run high-gray-run emphasis), and two size-zone matrix (high-gray-zone emphasis and short-zone high-gray emphasis) textures were computed. The relationship between the relative difference of each measure at different treatment time points and the pathologic response and overall survival was assessed using the area under the receiver-operating-characteristic curve (AUC) and Kaplan-Meier statistics, respectively.

RESULTS

All Textures, except Homogeneity, were better related to pathologic response than SUVmax and SUVmean. Entropy was found to significantly distinguish non-responders from the complete (AUC = 0.79, p = 1.7 × 10(-4)) and partial (AUC = 0.71, p = 0.01) responders. Non-responders can also be significantly differentiated from partial and complete responders by the change in the run-length and size-zone matrix textures (AUC = 0.71-0.76, p ≤ 0.02). Homogeneity, SUVmax, and SUVmean failed to differentiate between any of the responders (AUC = 0.50-0.57, p ≥ 0.46). However, none of the measures were found to significantly distinguish between complete and partial responders with AUC <0.60 (p = 0.37). Median Entropy and RLM textures significantly discriminated patients with good and poor survival (log-rank p < 0.02), while all other textures and survival were poorly related (log-rank p > 0.25).

CONCLUSION

For the patients studied, temporal changes in Entropy and all RLM were better correlated with pathological response and survival than the SUV measures. The hypothesis that these metrics can be used as clinical predictors of better patient outcomes will be tested in a larger patient dataset in the future.

Predictive value of repeated F-18 FDG PET/CT parameters changes during preoperative chemoradiotherapy to predict pathologic response and overall survival in locally advanced esophageal adenocarcinoma patients

INTRODUCTION

The goal of the current study was to investigate the predictive and prognostic values of repeated F-18 FDG PET/CT parameter changes for prediction of complete pathologic response (pCR) in patients with adenocarcinoma of locally advanced esophageal cancer (LAEC) who received preoperative concurrent chemoradiotherapy (PCRT).

METHODS

A total 53 patients with LAEC patients were included in the current study. All patients were evaluated by F-18 FDG PET/CT before and during chemoradiotherapy. The percent changes (∆, %) in F-18 FDG PET/CT parameters were used to predict pCR and to calculate overall survival (OS). The predictive value for pCR of F-18 FDG PET/CT cutoff values was determined by ROC analysis. The prognostic significance was assessed using Kaplan-Meier analysis.

RESULTS

pCR occurred in 15 patients (28.3 %). When ΔSUVmax > 23.5 % was used as cutoff, the sensitivity and specificity of F-18 FDG PET/CT for prediction of pCR were 100 % and 52.6, respectively. The AUC was 0.750 (95 % CI; 0.612-0.859), and standard error (SE) was 0.0633 (p = 0.0002). ΔMTV resulted in 80 % sensitivity, 76.3 % specificity, and 0.731 AUC (95 % CI; 0.591-0.843, SE = 0.077, p = 0.0027) for cutoff values >25.5 %. When ΔTLG > 44.8 % was used as cutoff, the sensitivity and specificity of F-18 FDG PET/CT for prediction of pCR were 100 and 65.8 %, respectively. The AUC was 0.893 (95 % CI; 0.777-0.961), and SE was 0.0431 (p < 0.0001). Kaplan-Meier analysis showed that high ΔSUVmax, ΔMTV, and ΔTLG were associated with improved OS.

CONCLUSION

In conclusion, the current study shows the capability of the changes (Δ) in repeated F-18 FDG PET/CT parameters to predict the achievement of pCR during PCRT in LAEC patients. Among the parameters, the ΔSUVmax, ΔMTV, and ΔTLG were predictors for pCR and well associated with OS.

18-fluorodeoxy-glucose positron emission computed tomography as predictive of response after chemoradiation in oesophageal cancer patients

INTRODUCTION

The purpose of this study was to evaluate if a baseline, an interim or a post-chemoradiation (CTRT) 18-fluorodeoxy-glucose positron emission computed tomography (18F-FDG PET/CT) studies could provide information on pathologic response to CTRT and overall survival (OS).

MATERIALS AND METHODS

Thirty-one patients with histologically proven adenocarcinoma or squamous cell carcinoma of the oesophagus, fit for trimodality therapy were prospectively enrolled. Most were men (93.5%), and had a stage III cancer (74.2%). Chemotherapy consisted of oxaliplatin/5-fluorouracil (45.2%) and taxane/5-fluorouracil (54.8%). All patients underwent a baseline, an interim (performed 12 ± 2 days after the onset of CTRT) and a post-CTRT 18F-FDG PET/CT study. The 18F-FDG PET/CT variables evaluated were at baseline, interim and post-CTRT studies maximum standardised uptake value (SUV max) and total lesion glycolysis (TLG). Clinical and 18F-FDG PET/CT parameters were correlated with pathologic complete response (pathCR) and OS.

RESULTS

Among the 31 patients studied, 61.3% achieved a clinical complete response (cCR) and 87.1% had surgery. The median OS was 35.1 months (95% confidence interval (CI): 19.9-NA). PathCR rate was 22.2%. There was only a marginal association between cCR and pathCR (p = 0.06). None of the other variables was predictive of pathCR. There was association between OS and baseline TLG (p = 0.03) at the optimal cutoff TLG value of 75.15. Additionally, TLG and ΔTLG post-CTRT were also associated with OS (p = 0.01 and 0.03, respectively).

CONCLUSION

None of the PET parameters is predictive of pathCR but TLG at baseline and post-CTRT are prognostic of OS.

Value of CT–PET after neoadjuvant chemoradiation in the prediction of histological tumour regression, nodal status and survival in oesophageal adenocarcinoma

Background

The role of CT–PET after neoadjuvant chemoradiation (nCRT) for prediction of pathological response and oncological outcome in oesophageal and junctional adenocarcinoma (OAC) is unclear. The relationship between complete metabolic response (cMR), pathological complete response (pCR) and nodal status has not been clarified.

Methods

Patients with locally advanced OAC selected to receive nCRT and surgery with curative intent, on the basis of staging that included CT–PET positivity, were included. Repeat scanning (PET2) with an identical protocol was performed 2–4 weeks after completion of nCRT (cisplatin and 5-fluorouracil plus 44 Gy radiation). Changes in [18F]fluorodeoxyglucose uptake, considered as either a maximum standardized uptake value (SUVmax) or a relative reduction (%ΔSUVmax), and PET-predicted nodal status following nCRT were compared with histopathological response, histological node positivity and survival.

Results

One hundred consecutive patients with PET-positive OAC were studied. Following nCRT, PET2 identified M1 disease in 2·0 per cent of patients. There were no significant associations between PET2 SUVmax or %ΔSUVmax with respect to primary tumour stage (ypT) (P = 0.216 and P = 0·975 respectively), tumour regression grade (P = 0·109 and P = 0·232), pCR (P = 0·633 and P = 0·870) or complete resection (R0) (P = 0·440 and P = 0·235). The sensitivity of PET2 for ypN was 10 per cent. %ΔSUVmax was not associated with disease-free or overall survival (P = 0·162 and P = 0·154 respectively). Of 46 patients with a cMR on PET2, 37 (80 per cent) had histological evidence of residual tumour in the resected specimen, and cMR was not associated with overall survival benefit (P = 0·478).

Conclusion

CT–PET following nCRT for OAC has poor prognostic and discriminatory value for clinical application.

The application of functional imaging techniques to personalise chemoradiotherapy in upper gastrointestinal malignancies

Functional imaging gives information about physiological heterogeneity in tumours. The utility of functional imaging tests in providing predictive and prognostic information after chemoradiotherapy for both oesophageal cancer and pancreatic cancer will be reviewed. The benefit of incorporating functional imaging into radiotherapy planning is also evaluated. In cancers of the upper gastrointestinal tract, the vast majority of functional imaging studies have used (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET). Few studies in locally advanced pancreatic cancer have investigated the utility of functional imaging in risk-stratifying patients or aiding target volume definition. Certain themes from the oesophageal data emerge, including the need for a multiparametric assessment of functional images and the added value of response assessment rather than relying on single time point measures. The sensitivity and specificity of FDG-PET to predict treatment response and survival are not currently high enough to inform treatment decisions. This suggests that a multimodal, multiparametric approach may be required. FDG-PET improves target volume definition in oesophageal cancer by improving the accuracy of tumour length definition and by improving the nodal staging of patients. The ideal functional imaging test would accurately identify patients who are unlikely to achieve a pathological complete response after chemoradiotherapy and would aid the delineation of a biological target volume that could be used for treatment intensification. The current limitations of published studies prevent integrating imaging-derived parameters into decision making on an individual patient basis. These limitations should inform future trial design in oesophageal and pancreatic cancers.

Clinical value of hematologic test in predicting tumor response to neoadjuvant chemotherapy with esophageal squamous cell carcinoma

Background

To investigate the relationship between hematologic test results and the predictive effect of regression of esophageal cancer after neoadjuvant chemotherapy (NACT), we analyzed pre-NACT hematologic data and their relationship to tumor regression.

Methods

Thirty-eight consecutive patients with locally advanced squamous cell esophageal carcinoma who had undergone two cycles of paclitaxel/carboplatin NACT were enrolled. On the day prior to the first cycle of chemotherapy, hematologic tests, including routine blood test and biochemical examinations, were recorded. All patients were confirmed to have no history of hepatitis. Surgical resection was performed when clinical restaging showed effective regression. Histopathological examination was routinely performed to evaluate the postoperative effects of chemotherapy.

Results

After two cycles of NACT, tumor imaging evaluation showed that 27 of the 38 patients had CR and PR, including 25 patients who underwent radical esophagectomies. Six patients had stable disease and five patients had progressive disease. According to the hematologic test results before NACT, patients with higher white blood cell counts, lymphocyte percentages, mononuclear cell counts, neutrophilic granulocyte counts, and eosinophilic granulocyte counts and lower alanine aminotransferase (ALT) level had a significantly greater opportunity for an effective response.

Conclusion

Basal host immunologic function and hepatic function are associated with tumor response to NACT in patients with esophageal cancer. These parameters may have a certain predictive efficacy on NACT for esophageal squamous cell carcinoma.

Complete metabolic response is not uniformly predictive of complete pathologic response after induction therapy for esophageal cancer

BACKGROUND

Positron emission tomography scanning is used to assess response to induction therapy after treatment of esophageal cancer. A decrease in standardized uptake value has been correlated with response to therapy, with a standardized uptake value of zero often assumed to indicate complete absence of disease. We hypothesize that a significant number of patients may have residual esophageal cancer despite complete metabolic response (CMR).

METHODS

A prospective database was reviewed for esophageal cancer patients receiving induction therapy followed by esophagectomy on whom both preinduction and postinduction positron emission tomography scans were obtained. Patients with a postinduction SUV of 0 (or "no uptake") were categorized as complete metabolic responders. Survival was calculated by the Kaplan-Meier statistic.

RESULTS

Among 120 patients, 32 (27%) had postinduction CMR after chemotherapy (21 of 81, 26%) or chemoradiation (11 of 39, 28%). At surgery, 19 patients (59%) with CMR had residual disease, including 12 (38%) with nodal metastases. Even among patients with a negative postinduction biopsy, 4 of 10 (40%) had residual disease. Final pathologic stages of patients with CMR were yp0 (complete pathologic response) in 13 (41%), ypI in 4 (12%), ypII in 9 (28%), and ypIII in 6 (19%). Three-year survival was 83% in the CMR group versus 41% in the remainder of the cohort (p = 0.02).

CONCLUSIONS

A CMR on postinduction positron emission tomography scan predicts but should not be assumed to be synonymous with complete pathologic response in esophageal cancer patients. The presence of residual disease should be strongly considered despite CMR and negative biopsy in patients receiving induction therapy.

Apparent diffusion coefficient modifications in assessing gastro-oesophageal cancer response to neoadjuvant treatment: comparison with tumour regression grade at histology

OBJECTIVES

To assess changes in apparent diffusion coefficient (ΔADC) and volume (ΔV) after neoadjuvant treatment (NT), and tumour regression grade (TRG) in gastro-oesophageal cancers (GEC), and to discriminate responders from non-responders.

METHODS

Thirty-two patients with biopsy-proven locally-advanced GEC underwent diffusion weighted magnetic resonance imaging (DWI) pre- and post-NT. Lesion ADC, volume, ΔADC and ΔV were calculated. TRG 1-2-3 patients were classified as R; TRG 4-5 as non-responders. ΔADC-TRG and ΔV-TRG correlations, pre-NT and post-NT ADC, ΔADC and ΔV cut-off values for responders and non-responders were calculated. Two readers measured mean tumour ADCs and interobserver variability was calculated. (Spearman's and intraclass correlation coefficient [ICC]).

RESULTS

The interobserver reproducibility was very good both for pre-NT (Spearman's rho = 0.8160; ICC = 0.8993) and post-NT (Spearman's rho = 0.8357; ICC = 0.8663). Responders showed lower pre-NT ADC (1.32 versus 1.63 × 10(-3) mm(2)/s; P = 0.002) and higher post-NT ADC (2.22 versus 1.51 × 10(-3) mm(2)/s; P = 0.001) than non-responders and ADC increased in responders (ΔADC, 85.45 versus -8.21 %; P = 0.00005). ΔADC inversely correlated with TRG (r = -0.71, P = 0.000004); no difference in ΔV between responders and non-responders (-50.92 % versus -14.12 %; P = 0.068) and no correlation ΔV-TRG (r = 0.02 P = 0.883) were observed.

CONCLUSIONS

The ADC can be used to assess gastro-oesophageal tumour response to neoadjuvant treatment as a reliable expression of tumour regression.

KEY POINTS

• DWI is now being used to assess many cancers. • Change in ADC measurements offer new information about oesophageal tumours. • ADC changes are more reliable than dimensional criteria in assessing neoadjuvant treatment. • Such ADC assessment could optimise management of locally advanced gastro-oesophageal cancers.

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.

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.

Postchemoradiotherapy positron emission tomography predicts pathologic response and survival in patients with esophageal cancer

PURPOSE

To correlate the prechemoradiotherapy (CRT) and post-CRT metabolic tumor volume (MTV) on positron emission tomography (PET) scanning with the pathologic response and survival in patients receiving preoperative CRT for esophageal cancer.

MATERIALS AND METHODS

The medical records of 37 patients with histologically confirmed Stage I-IVA esophageal cancer treated with CRT with or without surgical resection were reviewed. Of the 37 patients, 21 received preoperative CRT (57%) and 16 received definitive CRT (43%). All patients had a pre-CRT and 32 had a post-CRT PET scan. The MTV was measured on the pre-CRT PET and post-CRT PET scan, respectively, using a minimum standardized uptake value (SUV) threshold x, where x = 2, 2.5, 3, or the SUV maximum × 50%. The total glycolytic activity (TGA(x)) was defined as the mean SUV × MTV(x). The MTV ratio was defined as the pre-CRT PET MTV/post-CRT MTV. The SUV ratio was defined similarly. A single pathologist scored the pathologic response using a tumor regression grade (TRG) scale.

RESULTS

The median follow-up was 1.5 years (range, 0.4-4.9). No significant correlation was found between any parameters on the pre-CRT PET scan and the TRG or overall survival (OS). Multiple post-CRT MTV values and post-TGA values correlated with the TRG and OS; however, the MTV(2.5(Post)) and TGA(2.5(Post)) had the greatest correlation. The MTV(2) ratio correlated with OS. The maximum SUV on either the pre-CRT and post-CRT PET scans or the maximum SUV ratio did not correlate with the TRG or OS. Patients treated preoperatively had survival similar compared with those treated definitively with a good PET response (p = 0.97) and significantly better than that of patients treated definitively with a poor PET response (p < 0.0001).

CONCLUSION

The maximum SUV was not a predictive or prognostic parameter. The MTV(2.5) and TGA(2.5) were useful markers for predicting the response and survival on the post-CRT PET scan. The MTV(2) ratio also correlated with survival. Post-CRT PET can potentially guide therapy after CRT.

Prognostic significance of SUV on PET/CT in patients with localised oesophagogastric junction cancer receiving neoadjuvant chemotherapy/chemoradiation:a systematic review and meta-analysis

OBJECTIVE

The objective of this study was to comprehensively review the evidence for use of pre-treatment, post-treatment and changes in tumour glucose uptake that were assessed by 18-fludeoxyglucose ((18)F-FDG) positron emission tomography (PET) early, during or immediately after neoadjuvant chemotherapy/chemoradiation to predict prognosis of localised oesophagogastric junction (AEG) cancer.

METHODS

We searched for articles published in English; limited to AEG; (18)F-FDG uptake on PET performed on a dedicated device; dealt with the impact of standard uptake value (SUV) on survival. We extracted an estimate of the log hazard ratios (HRs) and their variances and performed meta-analysis.

RESULTS

798 patients with AEG were included. And the scan time for (18)F-FDG-PET was as follows: prior to therapy (PET1, n=646), exactly 2 weeks after initiation of neoadjuvant therapy (PET2, n=245), and pre-operatively (PET3, n=278). In the two meta-analyses for overall survival, including the studies that dealt with reduction of tumour maximum SUV (SUV(max)) (from PET1 to PET2/PET3 and from PET1 to PET2), the results were similar, with the overall HR for non-responders being 1.83 [95% confidence interval (CI), 1.41-2.36] and 2.62 (95% CI, 1.61-4.26), respectively; as for disease-free survival, the combined HR was 2.92 (95% CI, 2.08-4.10) and 2.39 (95% CI, 1.57-3.64), respectively. The meta-analyses did not attribute significant prognostic values to SUV(max) before and during therapy in localised AEG.

CONCLUSION

Relative changes in FDG-uptake of AEG are better prognosticators. Early metabolic changes from PET1 to PET2 may provide the same accuracy for prediction of treatment outcome as late changes from PET1 to PET3.

PET and PET-CT in esophageal and gastric cancer

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

Metabolic response evaluation by PET during neoadjuvant treatment for adenocarcinoma of the esophagus and esophagogastric junction

Following several randomized trials, neoadjuvant therapy in adenocarcinoma of esophagus and the esophagogastric junction can be seen as an international standard. However, in a large proportion of patients the objective response achieved is unsatisfactory. These patients do not benefit from neoadjuvant therapy, but do suffer from toxic side effects; sometimes progressive and appropriate surgical therapy is delayed. For this reason, a diagnostic test that can accurately assess tumor response to neoadjuvant therapy might be of crucial importance. Response evaluation using CT scan, endoluminal ultrasound, or rebiopsy is not reliable. In recent times, response evaluation using 18FGD PET after and during neoadjuvant treatment is in the focus of clinical and scientific interest. Most studies have evaluated the diagnostic modalities for response to neoadjuvant treatment after completion of the treatment. Following the published data so far, FDG-PET seems to be less accurate after and during chemoradiation than after chemotherapy alone. The data of early response evaluation (14 days after the onset of chemotherapy) are very much encouraging; however, they have to be evaluated in an international randomized trial. Standardization of PET technology as well as defining the thresholds used for the estimation of early response is mandatory. So far, FDG-PET does not change treatment in esophageal and gastric cancer.

Detecting treatment response in a model of human breast adenocarcinoma using hyperpolarised [1-13C]pyruvate and [1,4-13C2]fumarate

BACKGROUND

The recent introduction of a dynamic nuclear polarisation technique has permitted noninvasive imaging of tumour cell metabolism in vivo following intravenous administration of (13)C-labelled cell substrates.

METHODS

Changes in hyperpolarised [1-(13)C]pyruvate and [1,4-(13)C(2)]fumarate metabolism were evaluated in both MDA-MB-231 cells and in implanted MDA-MB-231 tumours following doxorubicin treatment.

RESULTS

Treatment of MDA-MB-231 cells resulted in the induction of apoptosis, which was accompanied by a decrease in hyperpolarised (13)C label flux between [1-(13)C]pyruvate and lactate, which was correlated with a decrease in the cellular NAD(H) coenzyme pool. There was also an increase in the rate of fumarate conversion to malate, which accompanied the onset of cellular necrosis. In vivo, the decrease in (13)C label exchange between pyruvate and lactate and the increased flux between fumarate and malate, following drug treatment, were shown to occur in the absence of any detectable change in tumour size.

CONCLUSION

We show here that the early responses of a human breast adenocarcinoma tumour model to drug treatment can be followed by administration of both hyperpolarised [1-(13)C]pyruvate and [1,4-(13)C(2)]fumarate. These techniques could be used, therefore, in the clinic to detect the early responses of breast tumours to treatment.

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.

Added value of baseline 18F-FDG uptake in serial 18F-FDG PET for evaluation of response of solid extracerebral tumors to systemic cytotoxic neoadjuvant treatment: a meta-analysis

The purpose of this study was to test the hypothesis that the level of baseline (18)F-FDG uptake in the primary tumor adds value to its relative change in (18)F-FDG uptake in serial PET scans in predicting the histopathologic response to systemic cytotoxic neoadjuvant treatment of patients with solid extracerebral tumors.

METHODS

We performed a literature search from January 1995 through November 2008 using PubMed and Embase. Two reviewers independently selected eligible studies for possible inclusion in the meta-analysis by reviewing titles and abstracts. Inclusion criteria were at least 10 patients, (18)F-FDG PET before and after therapy, (18)F-FDG PET performed with the intention of monitoring the response of solid extracerebral tumors in humans to cytotoxic neoadjuvant systemic therapy, attenuation-corrected (18)F-FDG PET studies, and studies presenting individual patient data (PET results and histopathologic reference test after treatment). Multilevel logistic regression was used to assess the effect of relative change of (18)F-FDG uptake ([baseline - end]/baseline) and baseline (18)F-FDG uptake value with type of tumor and type of treatment as level 1 covariates.

RESULTS

Nineteen studies (all observational; a total of 438 patients [median, 23 patients per study; range, 10-40]) were included, aiming at the accuracy of PET versus histopathology. To quantify PET, maximum standardized uptake value (SUV) was used in 6 studies, mean SUV in 7, SUV (subtype unclear) in 1, tumor-to-background ratio in 3, and dose uptake ratio in 1. The average overall histopathologic response rate was 0.47 (median, 0.50), ranging from 0.17 to 0.88. The relative change in (18)F-FDG uptake was the strongest indicator (P < 0.0001) for tumor response. Baseline (18)F-FDG was not significantly associated as a main factor; however, a significant interaction of baseline uptake and relative change after therapy was observed (P < 0.001).

CONCLUSION

Relative change in (18)F-FDG uptake was the strongest indicator for tumor response, but the level of baseline (18)F-FDG uptake in the primary tumor provided additional information about prediction of response to therapy. These data corroborate and extend the need for standardization, quality assurance, and control of PET studies quantifying (18)F-FDG in oncologic treatment monitoring.

18-Fluorodeoxyglucose positron emission tomography as a tool for response prediction in solid tumours

Current response guidelines for the treatment of solid tumours are based on CT criteria. Over the last decades new techniques have emerged to evaluate cancer therapy. FDG-PET scanning is a more functional imaging technique, which can measure differences in metabolic activity. Although it has a low specificity, studies show that it can outperform classical CT scanning criteria. Especially in lung, breast and oesophageal cancer it can predict response earlier in the neo-adjuvant setting. This could reduce the use of ineffective cancer therapies, reducing costs and patient toxicity, and direct patients sooner towards effective therapy. The main problem with FDG-PET remains the difficulty in defining thresholds for response, as there is clearly a lack in large prospective randomized studies validating the use of FDG-PET in response guidelines.We give an overview of data on response prediction in solid tumours by the application of PET.

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.

F-18-FDG and C-11-Choline Positron Emission Tomography in Human Esophago-Gastric Cancer: Prediction of Response to Therapy

Background

To determine the utility of F-18-FDG and C-11-Choline uptake, in patients with esophageal and esophago-gastric junction tumors who are to undergo either neo-adjuvant or palliative chemotherapy, in predicting response (pathological and survival).

Methods

Eighteen patients with biopsy proven cancer were recruited prospectively. Patients underwent PET imaging before and during the first cycle of chemotherapy (seven and 14 days) with both F-18-FDG and C-11-Choline. Tracer uptake was quantified using Standardized Uptake Values. Pathological tumor response was determined using the Mandard criteria. Cellular proliferation was determined using ki-67 immunohistochemistry. Relationships between tracer uptake and response, one-year survival and cellular proliferation were determined.

Results

All 18 tumors were imaged by F-18-FDG PET compared to 16/18 with C-11-Choline. Change in uptake of either tracer did not correlate with pathological response. Pathological response did not influence survival (median-survival, responders = 16.1 months; non-responders = 19.0 months, p = 0.978). There was no significant correlation of change in tracer uptake with survival. C-11-Choline tumor uptake did not correlate with cellular proliferation.

Conclusion

F-18-FDG PET is superior for imaging of the primary tumor. Neither F-18-FDG nor C-11-Choline PET was able to predict response accurately.

[18F]-Fluorodeoxyglucose-positron emission tomography for the assessment of histopathologic response and prognosis after completion of neoadjuvant chemoradiation in esophageal cancer

OBJECTIVE

To evaluate the potential of [(18)F]-fluorodeoxyglucose-positron emission tomography (FDG-PET) after the completion of neoadjuvant chemoradiation for the assessment of histopathologic response and prognosis in the multimodality treatment of patients with esophageal cancer.

BACKGROUND

Combined chemoradiation with and without surgery are widely accepted treatment options for patients with locally advanced esophageal cancer. Evidence suggests that patients with response to chemoradiation have no additional benefit from surgery compared with definitive chemoradiation. However, there is still a great lack in noninvasive markers for response assessment in patients with esophageal cancer undergoing multimodality treatment. Interestingly, recent studies imply that FDG-PET significantly correlates with histopathologic response and survival in patients with esophageal cancer undergoing neoadjuvant chemotherapy followed by surgical resection.

METHODS

Study patients were recruited from a prospective clinical observation trial on neoadjuvant chemoradiation for esophageal cancer between 1997 and 2006. The study included 119 (98 men, 21 women; median age, 59.4 years; squamous cell cancer: 66; adenocarcinoma: 53) patients with locally advanced esophageal cancer (cT2- 4, N(x), M(0)). All patients received neoadjuvant chemoradiation (cisplatin, 5-FU, 36 Gy) and subsequently underwent transthoracic en bloc esophagectomy. Histomorphologic regression was defined as major histopathologic response when resected specimens contained less than 10% vital residual tumor cells (major response: 47 patients [39.5%]; minor response: 72 patients [60.5%]). FDG-PET was performed before and 2 to 3 weeks after the end of chemoradiation with assessment of the intratumoral FDG-uptake (pretreatment standardized uptake value; post-treatment standardized uptake value; percentage change). These variables were correlated with histopathologic response and survival.

RESULTS

Major histomorphologic response was confirmed as an important prognostic factor (P = 0.005; log-rank test). Neoadjuvant chemoradiation led to a significant reduction of intratumoral FDG-uptake (P = 0.0001). A nonsignificant association was seen between major responders and FDG-PET results (P = 0.056). However, the receiver operating characteristic analysis could not identify a standardized uptake value threshold with a relevant predictive value for histomorphologic response. No significant association between metabolic imaging and prognosis was found.

CONCLUSION

FDG-PET seems not to be an imaging system that effectively characterizes the groups of major and minor response as well as survival in patients with esophageal cancer after multimodality treatment.

Whole body 18F-FDG PET predicts progression free and overall survival in squamous cell carcinoma of the esophagus: results of a prospective trial

BACKGROUND AND OBJECTIVES

18F-FDG PET yields physiologic information that allows for identifying cancer based on altered tissue metabolism. The aim of this study was to prospectively validate the predictive value of positron emission tomography (PET) in squamous cell carcinoma (SCC) of the esophagus treated by pre-operative chemotherapy followed by esophagectomy.

DESIGN AND SETTING

Prospective efficacy and toxicity study of patients enrolled between January 1999 and September 2003.

PATIENTS AND METHODS

Twenty-one patients with SCC of the esophagus who were potentially resectable underwent 18F-FDG PET imaging before the first cycle of neoadjuvant chemotherapy and at least 14 days after the third cycle. A patient was classified as a metabolic responder when the metabolic activity of the primary tumor as measured by the maximum standardized uptake values had decreased by 50% or more at the time of the second 18F-FDG PET.

RESULTS

The median age of the study cohort was 60 years with a range of 39-70 years; 12 patients were males and 9 were females. 18F-FDG PET had increased activity in the primary tumor in all patients. Metabolic response occurred in 14/21 patients (66%), while 7/21 (33%) patients did not show a metabolic response. Metabolic responders had a high clinical response rate (92%), a median progression free survival (PFS) of 16.4 months and a median overall survival (OS) of 35.3 months. In contrast, prognosis was poor for metabolic non-responders with a clinical response rate of 42% (P=.025), a median PFS of 7.13 months (P=.032) and median OS of 12 months (P=.038).

CONCLUSION

Our results demonstrate that changes in tumor metabolic activity after neoadjuvant chemotherapy predicts PFS and OS in esophageal SCC patients.

Monitoring response to therapeutic interventions in patients with cancer

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

Proteomic and metabolic prediction of response to therapy in gastrointestinal cancers

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

Positron emission tomography for monitoring response to neoadjuvant therapy in patients with oesophageal and gastro-oesophageal junction carcinoma

AIMS

The aim of this review is to consolidate our knowledge on an important and rapidly expanding area of expertise. Numerous methods for predicting response (in terms of pathological response and survival) to neoadjuvant therapy (chemotherapy/chemo-radiotherapy) in oesophageal and junctional cancers have been proposed. This review concerns itself only with the use of positron emission tomography for such a purpose. At present there are no standardised criteria amongst PET trials as to what determines a response according to PET, what is the optimal time to perform PET in relation to the timing of neoadjuvant therapy, and what is the ideal method of quantifying PET tracer uptake.

METHODS

An electronic search was performed of PubMed, Ovid and Embase websites to identify studies, in the English language, using the search terms: PET; oesophageal; oesophago-gastric; survival; cancer; response; chemotherapy and chemo-radiotherapy. The reference lists were searched manually to identify further relevant studies.

RESULTS

Twenty-two studies were identified, all using (18)FDG as the tracer, using PET to predict response in terms of pathological response and survival following neoadjuvant therapy (chemotherapy/chemo-radiotherapy). PET had a varying degree of success in predicting both pathological response and survival outcomes, with only one study using PET to influence management decisions.

CONCLUSIONS

PET seems a promising technique, but large-scale conclusions are hindered by small study numbers, lack of criteria as to what constitutes a response and markedly differing PET imaging times. A large randomised trial concerning a homogeneous group of patients and tumours is required before PET might be used to influence management.

Prognostic value of maximum standardized uptake values from preoperative positron emission tomography in resectable adenocarcinoma of the esophagus treated by surgery alone

Preoperative staging for esophageal adenocarcinoma is suboptimal for predicting outcomes when compared with pathological data. The aim of this study was to assess if the quantitative values obtained by preoperative 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) are independent prognostic indicators for survival in patients with resectable adenocarcinoma of the esophagus undergoing surgical treatment without neoadjuvant therapy. Patients were identified from a prospective database, survival analyses were undertaken using log rank and Cox method. The median follow-up was 44 months (range 18-61 months). Between November 2002 and November 2005, 45 consecutive patients underwent FDG-PET followed by surgery. The median age was 72 years (range 38-82 years). On univariate analysis of overall survival and disease-free survival, preoperative FDG-PET maximum standardized uptake value (SUV(max); P= 0.008 and P= 0.015, respectively) and postoperative pathological stage (P= 0.001 and P= 0.001, respectively) as well as postoperative histological grade (P= 0.001 and P= 0.001, respectively) were significantly associated with outcome. Multivariate analysis demonstrated that only the postoperative pathological variables were independent predictors of outcome (Wald 11.81, P= 0.001). Preoperative FDG-PET SUV(max) is associated with outcome after esophageal adenocarcinoma resection but remains less accurate than postoperative variables. A high FDG-PET SUV(max) could be used to identify a high-risk population who would benefit most from neoadjuvant therapies.

Clinical role of 18F-fluorodeoxyglucose positron emission tomography/computed tomography in post-operative follow up of gastric cancer: Initial results

AIM: To evaluate the clinical role of ¹⁸F-fluorodeo-xyglucose positron emission and computed tomography (¹⁸F-FDG PET/CT) in detection of gastric cancer recurrence after initial surgical resection.

METHODS: In the period from January 2007 to May 2008, 23 patients who had previous surgical resection of histopathologically diagnosed gastric cancer underwent a total of 25 ¹⁸F-FDG PET/CT scans as follow-up visits in our center. The standard of reference for tumor recurrence consisted of histopathologic confirmation or clinical follow-up information for at least 5 mo after PET/CT examinations.

RESULTS: PET/CT was positive in 14 patients (61%) and negative in 9 (39%). When correlated with final diagnosis, which was confirmed by histopathologic evidence of tumor recurrence in 8 of the 23 patients (35%) and by clinical follow-up in 15 (65%), PET/CT was true positive in 12 patients, false positive in 2, true negative in 8 and false negative in 2. Overall, the accuracy of PET/CT was 82.6%, the negative predictive value (NPV) was 77.7%, and the positive predictive value (PPV) was 85.7%. The 2 false positive PET/CT findings were actually chronic inflammatory tissue lesions. For the two patients with false negative PET/CT, the final diagnosis was recurrence of mucinous adenocarcinoma in the anastomosis in one patient and abdominal wall metastasis in the other. Importantly, PET/CT revealed true-positive findings in 11 (47.8%) patients who had negative or no definite findings by CT. PET/CT revealed extra-abdominal metastases in 7 patients and additional esophageal carcinoma in one patient. Clinical treatment decisions were changed in 7 (30.4%) patients after introducing PET/CT into their conventional post-operative follow-up program.

CONCLUSION: Whole body ¹⁸F-FDG PET/CT was highly effective in discriminating true recurrence in post-operative patients with gastric cancer and had important impacts on clinical decisions in a considerable portion of patients.