Utility of 18F-FDG PET for Predicting Histopathologic Response in Esophageal Carcinoma following Chemoradiation

Novel Advances in Qualitative Diagnostic Imaging for Decision Making in Multidisciplinary Treatment for Advanced Esophageal Cancer

Background: Recently, neoadjuvant therapy and the succeeding surgery for advanced esophageal cancer have been evaluated. In particular, the response to the therapy has been found to affect surgical outcomes, and thus a precise evaluation of treatment effect is important for this strategy. In this study, articles on qualitative diagnostic modalities to evaluate tumor activities were reviewed, and the diagnostic indices were examined. Methods: For prediction of the effect, perfusion CT and diffusion MRI were estimated. For the histological response evaluation, perfusion CT, diffusion-MRI, and FDG-PET were estimated. For downstaging evaluation of T4, tissue-selective image reconstruction using enhanced CT was estimated and diagnostic indices were reviewed. Results: The prediction of the effect using perfusion CT with 'pre CRT blood flow' and diffusion MRI with 'pre CRT ADC value'; the estimation of the histological response using perfusion CT with 'post CRT blood flow reduction, using diffusion MRI with 'post CRT ADC increasing', and using FDG-PET with 'post CRT SUV reduction'; and the downstaging evaluation of T4 using CT image reconstruction with 'fibrous changed layer' were performed well, respectively. Conclusions: Qualitative imaging modalities for prediction or response evaluation of neoadjuvant therapy for progressive esophageal cancer were useful for the decision making of the treatment strategy of the multidisciplinary treatment.

Potential Predictive Immune and Metabolic Biomarkers of Tumor Microenvironment Regarding Pathological and Clinical Response in Esophageal Cancer After Neoadjuvant Chemoradiotherapy: A Systematic Review

INTRODUCTION

The tumor microenvironment (TME) plays a crucial role in therapy response and modulation of immunologic surveillance. Adjuvant immunotherapy has recently been introduced in post-surgery treatment of locally advanced esophageal cancer (EC) with residual pathological disease after neoadjuvant chemoradiotherapy (nCRT). F-18 fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) remains a valuable imaging tool to assess therapy response and to visualize metabolic TME; however, there is still a paucity in understanding the interaction between the TME and nCRT response. This systematic review investigated the potential of TME biomarkers and 18F-FDG-PET/CT features to predict pathological and clinical response (CR) after nCRT in EC.

METHODS

A literature search of the Medline and Embase electronic databases identified 4190 studies. Studies regarding immune and metabolic TME biomarkers and 18F-FDG-PET/CT features were included for predicting pathological response (PR) and/or CR after nCRT. Separate analyses were performed for 18F-FDG-PET/CT markers and these TME biomarkers.

RESULTS

The final analysis included 21 studies-10 about immune and metabolic markers alone and 11 with additional 18F-FDG-PET/CT features. High CD8 infiltration before and after nCRT, and CD3 and CD4 infiltration after nCRT, generally correlated with better PR. A high expression of tumoral or stromal programmed death-ligand 1 (PD-L1) after nCRT was generally associated with poor PR. Moreover, total lesion glycolysis (TLG) and metabolic tumor volume (MTV) of the primary tumor were potentially predictive for clinical and PR.

CONCLUSION

CD8, CD4, CD3, and PD-L1 are promising immune markers in predicting PR, whereas TLG and MTV are potential 18F-FDG-PET/CT features to predict clinical and PR after nCRT in EC.

18F-Fluorodeoxyglucose Positron Emission Tomography Parameters can Predict Long-Term Outcome Following Trimodality Treatment for Oesophageal Cancer

AIMS

¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸FDG-PET/CT) is routinely used for the pre-treatment staging of oesophageal or gastro-oesophageal junction cancers (EGEJC). The aim of this study was to identify objective ¹⁸FDG-PET/CT-derived parameters that can aid in predicting the patterns of recurrence and prognostication in patients with EGEJC.

PATIENTS AND METHODS

EGEJC patients referred for consideration of preoperative chemoradiation therapy were identified and clinicopathological data were collected. ¹⁸FDG-PET/CT imaging data were reviewed and correlated with treatment outcomes. Maximum standardised uptake value (SUV_max), metabolic tumour volume (MTV) and total lesion glycolysis were assessed and association with recurrence-free survival (RFS), locoregional recurrence-free survival (LR-RFS), oesophageal cancer-specific survival (ECSS) and overall survival were evaluated using receiver operating characteristic curves, as well as Cox regression and Kaplan-Meier models.

RESULTS

In total, 191 EGEJC patients completed trimodality treatment and 164 with ¹⁸FDG-PET/CT data were included in this analysis. At the time of analysis, 15 (9.1%), 70 (42.7%) and two (1.2%) patients were noted to have locoregional, distant and both locoregional and distant metastases, respectively. The median RFS was 30 months (9.6-50.4) and the 5-year RFS was 31.1%. The 5-year overall survival and ECSS were both noted to be 34.8%. Pre-treatment MTV₂₅ > 28.5 cm³ (P = 0.029), MTV₄₀ > 12.4 cm³ (P = 0.018) and MTV₅₀ > 10.2 cm³ (P = 0.005) predicted for worse LR-RFS, ECSS and overall survival for MTV definition of voxels ≥25%, 40% and 50% of SUV_max.

CONCLUSION

¹⁸FDG-PET/CT parameters MTV and total lesion glycolysis are useful prognostic tools to predict for LR-RFS, ECSS and overall survival in EGEJC. MTV had the highest accuracy in predicting clinical outcomes. The volume cut-off points we identified for different MTV thresholds predicted outcomes with significant accuracy and may potentially be used for decision making in clinical practice.

Advances in image-guided drug delivery for antibacterial therapy

The emergence of antibiotic-resistant bacterial strains is seriously endangering the global healthcare system. There is an urgent need for combining imaging with therapies to realize the real-time monitoring of pathological condition and treatment progress. It also provides guidance on exploring new medicines and enhance treatment strategies to overcome the antibiotic resistance of existing conventional antibiotics. In this review, we provide a thorough overview of the most advanced image-guided approaches for bacterial diagnosis (e.g., computed tomography imaging, magnetic resonance imaging, photoacoustic imaging, ultrasound imaging, fluorescence imaging, positron emission tomography, single photon emission computed tomography imaging, and multiple imaging), and therapies (e.g., photothermal therapy, photodynamic therapy, chemodynamic therapy, sonodynamic therapy, immunotherapy, and multiple therapies). This review focuses on how to design and fabricate photo-responsive materials for improved image-guided bacterial theranostics applications. We present a potential application of different image-guided modalities for both bacterial diagnosis and therapies with representative examples. Finally, we highlighted the current challenges and future perspectives image-guided approaches for future clinical translation of nano-theranostics in bacterial infections therapies. We envision that this review will provide for future development in image-guided systems for bacterial theranostics applications.

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

Background

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

Methods

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

Results

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

Conclusion

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

The Role of the TP53 Pathway in Predicting Response to Neoadjuvant Therapy in Esophageal Adenocarcinoma

PURPOSE

In patients with locally advanced esophageal adenocarcinoma, response to neoadjuvant therapy strongly predicts survival, but robust molecular predictors of response have been lacking. We therefore sought to discover meaningful predictors of response in these patients.

EXPERIMENTAL DESIGN

We retrospectively identified all patients with adenocarcinoma of the lower esophagus or gastroesophageal junction who (i) were treated with multimodality therapy with curative intent at our institution from 2014 through 2020 and (ii) underwent prospective sequencing by Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets. Clinicopathologic and genomic data were analyzed to identify potential genomic features, somatic alterations, and oncogenic pathways associated with treatment response.

RESULTS

In total, 237 patients were included. MDM2 amplification was independently associated with poor response to neoadjuvant therapy [OR, 0.10 (95% confidence interval, 0.01-0.55); P = 0.032], when accounting for significant clinicopathologic variables, including clinical stage, tumor grade, and chemotherapy regimen. Moreover, TP53 pathway alterations, grouped according to inferred severity of TP53 dysfunction, were significantly associated with response to neoadjuvant therapy (P = 0.004, q = 0.07). Patients with MDM2 amplifications or truncating biallelic TP53 mutations had similar outcomes in terms of poor responses to neoadjuvant therapy and, consequently, shorter progression-free survival, compared with patients with TP53 pathway wild-type tumors. Thus, worsening TP53 dysfunction was directly correlated with worse outcomes.

CONCLUSIONS

MDM2 amplification and TP53 status are associated with response to therapy in patients with esophageal adenocarcinoma. Given the dearth of actionable targets in esophageal adenocarcinoma, MDM2 inhibition, in combination with cytotoxic chemotherapy, may represent an important therapeutic strategy to overcome treatment resistance and improve outcomes in these patients.

18F-FDG-PET/CT-measured parameters as potential predictors of residual disease after neoadjuvant chemoradiotherapy in patients with esophageal carcinoma

Objective

To evaluate the maximum and mean standardized uptake values, together with the metabolic tumor value and the total lesion glycolysis, at the primary tumor site, as determined by ¹⁸F-fluorodeoxyglucose positron-emission tomography/computed tomography (¹⁸F-FDG-PET/CT), performed before and after neoadjuvant chemoradiotherapy (nCRT), as predictors of residual disease (RD) in patients with esophageal cancer.

Materials and Methods

The standardized uptake values and the volumetric parameters (metabolic tumor value and total lesion glycolysis) were determined by ¹⁸F-FDG-PET/CT to identify RD in 39 patients before and after nCRT for esophageal carcinoma. We used receiver operating characteristic curves to analyze the diagnostic performance of ¹⁸F-FDG-PET/CT parameters in the definition of RD. The standard of reference was histopathological analysis of the surgical specimen.

Results

Eighteen patients (46%) presented RD after nCRT. Statistically significant areas under the curve (approximately 0.72) for predicting RD were obtained for all four of the variables evaluated after nCRT. Considering the presence of visually detectable uptake (higher than the background level) at the primary tumor site after nCRT as a positive result, we achieved a sensitivity of 94% and a specificity of 48% for the detection of RD.

Conclusion

The use of ¹⁸F-FDG-PET/CT can facilitate the detection of RD after nCRT in patients with esophageal cancer.

Trimodality therapy for locally advanced esophageal squamous cell carcinoma: the role of volume-based PET/CT in patient management and prognostication

PURPOSE

To evaluate the role of positron emission tomography/computed tomography (PET/CT) in predicting pathologic complete response (pCR) and identify relevant prognostic factors from clinico-imaging-pathologic features of locally advanced esophageal squamous cell carcinoma (eSCC) patients undergoing trimodality therapy.

METHODS

We evaluated 275 patients with eSCCs of T3-T4aN0M0 and T1-T4aN1-N3M0 who received trimodality therapy. We correlated volume-based PET/CT parameters before and after concurrent chemoradiation therapy with pCR after surgery, clinico-imaging-pathologic features, and patient survival.

RESULTS

pCR occurred in 75 (27.3%) of 275 patients, of whom 61 (80.9%) showed 5-year survival. Pre-total lesion glycolysis (pre-TLG, OR = 0.318, 95% CI 0.169 to 0.600), post-metabolic tumor volume (post-MTV, OR = 0.572, 95% CI 0.327 to 0.999), and % decrease of average standardized uptake value (% SUVavg decrease, OR = 2.976, 95% CI = 1.608 to 5.507) were significant predictors for pCR. Among them, best predictor for pCR was pre-TLG with best cutoff value of 205.67 and with AUC value of 0.591. Performance status (HR = 5.171, 95% CI 1.737 to 15.397), pathologic tumor size (HR = 1.645, 95% CI 1.351 to 2.002), pathologic N status (N1, HR = 1.572, 95% CI 1.010 to 2.446; N2, HR = 3.088, 95% CI 1.845 to 5.166), and post-metabolic tumor volume (HR = 1.506, 95% CI 1.033 to 2.195) were significant predictors of overall survival.

CONCLUSION

Pre-TLG, post-MTV, and % SUVavg decrease are predictive of pCR. Additionally, several clinico-imaging-pathologic factors are significant survival predictors in locally advanced eSCC patients undergoing trimodality therapy.

Comparison of treatment response assessed by 18F-FDG PET/CT with the histopathological response using tumor regression grading on surgically resected specimen following neoadjuvant chemotherapy in squamous cell carcinoma of esophagus

BACKGROUND

For the response assessment after chemotherapy, gold standard is always the histopathological response. However, metabolic response can also guide further treatment. Herein, this study aimed to evaluate metabolic response assessment to neoadjuvant chemotherapy in squamous cell carcinoma esophagus using PET response criteria in solid tumors (PERCIST) criteria with taking histopathological response by tumor regression grading as the standard method.

METHODS

Total fifty-seven patients with squamous cell carcinoma esophagus were enrolled between April 2017 to December 2018 for this prospective study. All patients were undergone for baseline PET scan before going for neoadjuvant chemotherapy. Repeat PET scan was done after neoadjuvant chemotherapy. Operable patients were taken for surgery. Final histological response was assessed by Mandard grading. Three metabolic tools [maximum standardized uptake value (SUVmax), tumor regression grading, PERCIST] were compared.

RESULTS

The mean SULpeak of the primary lesion was 11.7 ± 5.5 (median, 10.2, range 5.5-31.8). The average percentage change (%Δ) in SUVmax was 42.9 ± 26.3. On histopathology, 5 (13.1%) patients showed complete pathological response, whereas grade II, III, IV and V in 8 (21.1%), 12 (31.6%), 10 (26.3%) and 3 (7.8%) respectively. On comparison of PERCIST with Mandard grading, agreement analysis showed that there was moderate agreement (k, 0.48). %ΔSUV peak change showed a strong correlation with %ΔSUVmax (P = 0.01) and percentage tumor to liver ratio change (P = 0.01). On comparison, these metabolic response tools showed a weak agreement (k, 0.28 with tumor to liver ratio, k, 0.38 with SUVmax).

CONCLUSION

After neoadjuvant chemotherapy, 18F-fluorodeoxyglucose PET/CT can help to assess the response and guide the treatment. However, a larger study is warranted to evaluate their correlation with pathological response.

Utility of positron emission-computed tomography for predicting pathological response in resectable oesophageal squamous cell carcinoma after neoadjuvant chemoradiation

OBJECTIVES

For patients with locally advanced oesophageal cancer, improved complete pathological response after neoadjuvant chemoradiation (nCRT) and the detrimental effects on the quality of life related to oesophagectomy have led to the need for a reliable method to select patients who have achieved complete pathological response and do not need surgery. The reliability of 18F-fluorodeoxyglucose positron emission-computed tomography (PET-CT) for predicting the pathological response after nCRT was evaluated.

METHODS

Patients with locally advanced oesophageal cancer who were treated with nCRT and oesophagectomy from July 2010 to February 2017 were analysed. On the post-nCRT PET-CT, a complete metabolic response was defined as all tumourous lesions demonstrating maximum standardized uptake value (SUVmax) ≤2.5. To minimize the effect of radiation-induced oesophagitis, complete metabolic response was also defined as no viable lesion distinguishable from the background with diffuse uptake. The sensitivity, specificity, positive predictive value and negative predictive value were analysed for SUVmax, [X]ΔSUVmax and %ΔSUVmax.

RESULTS

A total of 158 patients with oesophageal squamous cell carcinoma were analysed. The rate of complete pathological response was 27.8%, and that of complete metabolic response was 7.6%. The sensitivity, specificity, positive predictive value and negative predictive value based on SUVmax ≤2.5 and visual normalization were 95%, 14%, 74% and 50%, respectively. Analysis for [X]ΔSUVmax and %ΔSUVmax using the optimal cut-off values determined by the receiver operating characteristic curves did not show an improved predictive efficacy.

CONCLUSIONS

PET-CT is not a reliable tool for predicting pathological response. Patients diagnosed with resectable oesophageal cancer who underwent neoadjuvant therapy should not be exempt from surgery based on PET-CT results.

Prognostic value of lymph node to primary tumor standardized uptake value ratio in unresectable esophageal cancer

Background

Unresectable esophageal cancer harbors high mortality despite chemoradiotherapy. Better patient selection for more personalized management may result in better treatment outcomes. We presume the ratio of maximum standardized uptake value (SUV) of metastatic lymph nodes to primary tumor (NTR) in 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography/computed tomography (FDG PET/CT) may provide prognostic information and further stratification of these patients.

Methods

The patients with non-metastatic and unresectable esophageal squamous cell carcinoma (SCC) receiving FDG PET/CT staging and treated by chemoradiotherapy were retrospectively reviewed. Receiver operating characteristic (ROC) analysis was performed to determine the optimal cut-off value for NTR. Kaplan-Meier method and Cox regression model were used for survival analyses and multivariable analyses, respectively.

Results

From 2010 to 2016, 96 eligible patients were analyzed. The median follow-up time was 10.2 months (range 1.6 to 83.6 months). Using ROC analysis, the best NTR cut-off value was 0.46 for prediction of distant metastasis. The median distant metastasis-free survival (DMFS) was significantly lower in the high-NTR group (9.5 vs. 22.2 months, p = 0.002) and median overall survival (OS) (9.5 vs. 11.6 months, p = 0.013) was also significantly worse. Multivariable analysis revealed that NTR was an independent prognostic factor for DMFS (hazard ratio [HR] 1.81, p = 0.023) and OS (HR 1.77, p = 0.014).

Conclusions

High pretreatment NTR predicts worse treatment outcomes and could be an easy-to-use and helpful prognostic factor to provide more personalized treatment for patients with non-metastatic and unresectable esophageal SCC.

Phase II Feasibility and Biomarker Study of Neoadjuvant Trastuzumab and Pertuzumab With Chemoradiotherapy for Resectable Human Epidermal Growth Factor Receptor 2-Positive Esophageal Adenocarcinoma: TRAP Study

PURPOSE

Approximately 15% to 43% of esophageal adenocarcinomas (EACs) are human epidermal growth factor receptor 2 (HER2) positive. Because dual-agent HER2 blockade demonstrated a survival benefit in breast cancer, we conducted a phase II feasibility study of trastuzumab and pertuzumab added to neoadjuvant chemoradiotherapy (nCRT) in patients with EAC.

PATIENTS AND METHODS

Patients with resectable HER2-positive EAC received standard nCRT with carboplatin and paclitaxel and 41.4 Gy of radiotherapy, with 4 mg/kg of trastuzumab on day 1, 2 mg/kg per week during weeks 2 to 6, and 6 mg/kg per week during weeks 7, 10, and 13 and 840 mg of pertuzumab every 3 weeks. The primary end point was feasibility, defined as ≥ 80% completion of treatment with both trastuzumab and pertuzumab. An exploratory comparison of survival with a propensity score-matched cohort receiving standard nCRT was performed, as were exploratory pharmacokinetic and biomarker analyses.

RESULTS

Of the 40 enrolled patients (78% men; median age, 63 years), 33 (83%) completed treatment with trastuzumab and pertuzumab. No unexpected safety events were observed. R0 resection was achieved in all patients undergoing surgery, with pathologic complete response in 13 patients (34%). Three-year progression-free and overall survival (OS) were 57% and 71%, respectively (median follow-up, 32.1 months). Compared with the propensity score-matched cohort, a significantly longer OS was observed with HER2 blockade (hazard ratio, 0.58; 95% CI, 0.34 to 0.97). Results of pharmacokinetic analysis and activity on [18F]fluorodeoxyglucose positron emission tomography scans did not correlate with survival or pathologic response. Patients with HER2 3+ overexpression or growth factor receptor-bound protein 7 (Grb7) -positive tumors at baseline demonstrated significantly better survival (P = .007) or treatment response (P = .016), respectively.

CONCLUSION

Addition of trastuzumab and pertuzumab to nCRT in patients with HER2-positive EAC is feasible and demonstrates potentially promising activity compared with historical controls. HER2 3+ overexpression and Grb7 positivity are potentially predictive for survival and treatment response, respectively.

18F FDG-PET/CT evaluation of histological response after neoadjuvant treatment in patients with cancer of the esophagus or gastroesophageal junction

BACKGROUND

In most parts of the world, curatively intended treatment for esophageal cancer includes neoadjuvant therapy, either with chemoradiotherapy or chemotherapy alone, followed by esophagectomy. Currently 18F-FDG positron emission tomography/computed tomography (PET/CT) is used for preoperative disease staging, but is not well established in the evaluation of neoadjuvant treatment.

PURPOSE

To evaluate changes in PET parameters in relation to the histological primary tumor response in the surgical specimen in patients randomized to neoadjuvant chemoradiotherapy or chemotherapy.

MATERIAL AND METHODS

Patients were randomized between either neoadjuvant chemotherapy or chemoradiotherapy followed by esophagectomy.18F-FDG PET/CT exams were conducted at baseline and following neoadjuvant treatment. Standardized uptake ratio (SUR) values were measured in the primary tumor and compared as regards histological responders and non-responders as well as different treatment arms.

RESULTS

Seventy-nine patients were enrolled and 51 were available for analysis. A significant rate of SUR reduction was observed ( P = 0.02) in the primary tumor in histological responders compared to non-responders. Changes in SUR were significantly greater in responders following chemoradiotherapy ( P = 0.02), but not following chemotherapy alone ( P = 0.49). There was no statistically significant difference in SUR in patients with a complete histological response compared to those with a subtotal response.

CONCLUSION

Our results are similar to those of previous studies and show that changes in the rate of SUR can be used reliably to differentiate histological responders from non-responders after neoadjuvant treatment with either chemoradiotherapy or chemotherapy. Limitations of current PET technology are likely to restrict the possibility of accurately ruling out limited residual disease.

Prognostic value of SUR in patients with trimodality treatment of locally advanced esophageal carcinoma

The prognosis of patients with esophageal carcinoma remains dismal despite ongoing efforts to improve treatment options. For locally advanced tumors, several randomized trials have shown the benefit of neoadjuvant chemoradiation followed by surgery compared to surgery alone. The aim of this exploratory study was to evaluate the prognostic value of different baseline positron emission tomography (PET) parameters and their potentially additional prognostic impact at the end of neoadjuvant radiochemotherapy. Furthermore, the standard uptake ratio (SUR) as a new parameter for quantification of tumor metabolism was compared to the conventional PET parameters metabolic active volume (MTV), total lesion glycolysis (TLG), and standardized uptake value (SUV) taking into account known basic parameters. Methods:18F-FDG-PET/CT was performed in 76 consecutive patients ((60±10) years, 71 males) with newly diagnosed esophageal cancer before and during the last week of neoadjuvant radiochemotherapy. MTV of the primary tumor was delineated with an adaptive threshold method. The blood SUV was determined by manually delineating the aorta in the low dose CT. SUR values were computed as scan time corrected ratio of tumor SUVmax and mean blood SUV. Univariate Cox regression and Kaplan-Meier analysis with respect to locoregional control (LRC), freedom from distant metastases (FFDM), and overall survival (OS) was performed. Additionally, independence of PET parameters from standard clinical factors was analyzed with multivariate Cox regression. Results: In multivariate analysis two parameters showed a significant correlation with all endpoints: restaging MTV and restaging SUR. Furthermore, restaging TLG was prognostic for LCR and FFDM. For all endpoints the largest effect size was found for restaging SUR. The only basic factors remaining significant in multivariate analyses were histology for OS and FFDM and age for LRC. Conclusion: PET provides independent prognostic information for OS, LRC, and FFDM in addition to standard clinical parameters in this patient cohort. Our results suggest that the prognostic value of tracer uptake can be improved when characterized by SUR rather than by SUV. Overall, our investigation revealed a higher prognostic value of restaging parameters compared to baseline PET; therapy-adjustments would still be possible at this point of time. Further investigations are required to confirm these hypothesis-generating results.

Correlation of quantified metabolic activity in nonsmall cell lung cancer with tumor size and tumor pathological characteristics

The aim of this study was to evaluate the relationship between maximum standardized uptake value (SUVmax) with tumor size and tumor pathological characteristics as well as suggesting equations between SUVmax and tumor size in patients with nonsmall cell lung cancer (NSCLC) to help differentiate between pathology types.We retrospectively analyzed the fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) findings of 98 patients with NSCLC. Statistical differences were considered significant when P < .05. Correlation between SUVmax and other variables was determined by Pearson and Spearman correlation. Both linear and nonlinear regression analysis were used to determine equations between SUVmax and tumor size to help differentiate between pathology types.The mean SUVmax in patients with squamous cell carcinoma was significantly higher than that of adenocarcinoma (21.35 ± 1.73 vs 13.75 ± 0.89, P = .000). The results of regression analysis indicated that among all equations determined with relative accuracy, the "cubic equation" has the highest accuracy when considering the relationship between SUVmax and tumor size in patients with adenocarcinoma. In patients with squamous cell carcinoma, the most accurate equation was obtained using the "quadratic equation."There was a significant correlation between SUVmax and tumor differentiation and tumor size in patients with adenocarcinoma. SUVmax of patients with squamous cell carcinoma also had a significant correlation with tumor size. Overall SUVmax of patients with NSCLC could be predicted by tumor size value. In patients with squamous cell carcinoma compared with those with adenocarcinoma, SUVmax with less accuracy can be determined by tumor size. Linear regression analysis line slope can be used as an index for distinguishing adenocarcinoma from squamous cell carcinoma.

Surveillance or resection after chemoradiation in esophageal cancer

The treatment of locally advanced esophageal cancer continues to evolve. Previously, surgery was considered the foundation of treatment, but chemoradiation (CRT) has taken on a larger role both in the neoadjuvant setting and as definitive treatment. It has become clear that although some patients benefit from esophagectomy after CRT, a large subset of patients likely derive no benefit, and may be harmed by surgery. Some patients are cured from CRT alone and therefore do not need surgery. Another group of patients likely have metastatic disease at the time of local therapy that is just undetected on imaging and also do not benefit from surgery. A third group of patients will have persistent locoregional disease only after CRT. This last group is the subset who will actually benefit from surgery, but this likely comprises only a minority of patients with locally advanced disease. A strategy to maximize survival while minimizing unnecessary surgery is a reasonable goal, but present technology does not allow us to do this with certainty. Thus, the decision of whether to pursue resection or surveillance after CRT can be difficult as clinicians and patients try to balance the goal of maximizing the likelihood of cure against the risk of surgery and its impact on quality of life.

Significance of baseline FDG-PET/CT scan as a method of staging regional lymph nodes in patients with operable distal oesophageal or gastroesophageal junction adenocarcinoma

BACKGROUND

The new American Joint Committee on Cancer eighth edition (AJCC8) staging is the first to describe separate clinical and pathology staging systems, but still has low performance to predict prognosis in patients with oesophageal/gastroesophageal junction (O/GOJ) adenocarcinoma, who are candidates for surgery. Recent studies have demonstrated that O/GOJ cancer patients with 18F-fluorodeoxyglucose (FDG) avid regional lymph nodes (RLNs) may have poor prognosis. The aim of our study was to examine whether the baseline assessment of the FDG uptake of RLN improves the prognostic accuracy of the new AJCC8 staging.

PATIENTS AND METHODS

This single-centre retrospective study included patients with operable FDG avid O/GOJ adenocarcinoma treated with perioperative chemotherapy. All patients were reclassified according to the new AJCC8 clinical staging. Prognostic factors for time-to-progression (TTP) and overall survival (OS) were explored.

RESULTS

Of 430 patients included in the study, 180 (41.9%) had FDG avid RLN at baseline PET/CT scan before starting perioperative chemotherapy. The presence of FDG avid RLN was significantly and independently associated with shorter TTP and OS, especially in clinical stage III patients (p < .001 in both cases). Stage III patients with FDG avid RLN had similar TTP and OS to those with stage IVA. Classifying stage III patients with FDG avid RLN into stage IVA led to a significant improvement of the prognostic accuracy of the new AJCC8 clinical staging system (Harrell's concordance index improved from 0.555 to 0.588, p < .001). Of 430 patients starting perioperative chemotherapy, 332 underwent radical tumour resection. The presence of FDG avid RLN before starting perioperative chemotherapy could additionally predict a significantly shorter postoperative time-to-relapse and OS (p < .001 in both cases).

CONCLUSIONS

We propose that the incorporation of RLN status (by FDG PET/CT scan) into the AJCC8 staging system of O/GOJ adenocarcinoma improves its prognostic accuracy and may also improve treatment stratification.