Pretreatment F-18 FDG PET/CT Parameters to Evaluate Progression-Free Survival in Gastric Cancer. Nucl Med Mol Imaging. 2014;48:33-40. [PMID: 24900136 DOI: 10.1007/s13139-013-0243-3]

Predictive significance of 18F-FDG PET/CT metabolic parameters for the expression level of HER2 in gastric cancer

Objective

To investigate the predictive value of pertinent metabolic parameters of 18F-FDG PET/CT in relation to the expression level of human epidermal growth factor receptor 2 (HER2) in patients with gastric cancer.

Materials and methods

The data was retrospectively acquired from 105 patients who had been pathologically diagnosed gastric cancer prior to treatment at our institution, including clinical data, laboratory test results, histological information, 18F-FDG PET/CT metabolic parameters (including maximum standardized uptake value (SUVmax), mean standardized uptake value (SUVmean), peak standardized uptake value (SUVpeak), SUVmax normalized by lean body mass (SULmax), SUVmean normalized by lean body mass (SULmean), SUVpeak normalized by lean body mass (SULpeak), metabolic tumor volume (MTV), and total lesion glycolysis (TLG)), and HER2 expression level, from January 2018 to December 2022. The correlation between 18F-FDG PET/CT metabolic parameters and HER2 expression level was examined, and the predictive value of these measures for HER2 expression level was investigated.

Results

Among the 105 patients, 27 exhibited positive HER2 expression, while 78 demonstrated negative HER2 expression. Significant differences in MTV and TLG between patients exhibiting positive and negative HER2 expression (P < 0.05). The best cut-off values for MTV and TLG were 20.3 cm³ and 72.3 g, yielding accuracy rates of 90.2% and 89.0% for predicting positive HER2 expression, respectively. Our further grouped study shows that in the gastric adenocarcinoma and Lauren classification groups, MTV was significantly negatively correlated with HER2 positivity. Notably, in mixed tumors, the AUC value reached as high as 0.85.

Conclusions

The negative correlations between MTV/TLG and HER2 status demonstrated that HER2-positive tumors are associated with reduced metabolic burden, providing imaging biomarkers for clinical prognostic assessment. Notably, subgroup analysis in gastric adenocarcinoma and Lauren classification subgroups revealed significant negative associations between MTV and HER2 positivity, highlighting MTV's potential utility in predicting HER2 expression across histological subtypes of gastric cancer and supporting its role in precision oncology.

The value of a nomogram based on 18F-FDG PET/CT metabolic parameters and metabolic heterogeneity in predicting distant metastasis in gastric cancer

OBJECTIVE

To investigate the value of metabolic parameters and metabolic heterogeneity from pretreatment deoxy-2-[fluorine-18]-fluoro-D-glucose positron emission tomography/computed tomography (18F-FDG PET/CT) in predicting distant metastasis in gastric cancer.

METHODS

Eighty-six patients with pathologically confirmed gastric adenocarcinoma were included in this study. All patients underwent a whole-body 18F-FDG PET/CT scan before treatment. Clinicopathologic and imaging data were collected, including metabolic parameters such as maximum standardized uptake value (SUVmax), mean standardized uptake value (SUVmean), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) of the primary gastric cancer lesions. Heterogeneity index (HI)-1 was expressed as the absolute value of the linear regression slopes between the MTVs at different SUVmax thresholds (40% × SUVmax, 80% × SUVmax), while HI-2 was expressed as the difference between SUVmax and SUVmean. Patients were randomly divided into training and validation cohorts at a 7:3 ratio. The correlation between the above parameters and distant metastasis in gastric cancer was analyzed using the training cohort. A nomogram prediction model was then established and later verified with the validation cohort. Finally, decision curve analysis was used to evaluate the clinical utility of the model.

RESULTS

This study included 86 patients with gastric cancer, with 60 (69.8%) in the training cohort and 26 (30.2%) in the validation cohort. There was no significant difference in the balanced comparison between both cohorts (all P > .05). Among all patients, 31 (36.0%) developed distant metastasis, while 55 (64.0%) did not. In patients who developed distant tumor metastasis, carcinoembryonic antigen, carbohydrate antigen (CA)12-5, CA19-9, CA72-4, MTV, TLG, and HI-1 were significantly higher than in patients without distant metastasis (all P < .05). Multivariate logistic regression analysis identified CA72-4 (OR: 1.151, 95% CI: 1.020-1.300, P = .023) and HI-1 (OR: 1.647, 95% CI: 1.063-2.553, P = .026) as independent risk factors for predicting distant metastasis in gastric cancer. The nomogram constructed from this analysis exhibited high predictive efficacy in the training (AUC: 0.874, 95% CI: 0.766-0.983) and validation (AUC: 0.915, 95% CI: 0.790-1.000) cohorts, providing a net clinical benefit for patients.

CONCLUSION

HI-1 is an independent risk factor for predicting distant metastasis in gastric cancer. A comprehensive prediction model combining HI-1 with the tumor marker CA72-4 can increase the net clinical benefit for patients.

Tata Memorial Centre Evidence Based Use of Nuclear medicine diagnostic and treatment modalities in cancer

ABSTRACT

PET/CT and radioisotope therapy are diagnostic and therapeutic arms of Nuclear Medicine, respectively. With the emergence of better technology, PET/CT has become an accessible modality. Diagnostic tracers exploring disease-specific targets has led the clinicians to look beyond FDG PET. Moreover, with the emergence of theranostic pairs of radiopharmaceuticals, radioisotope therapy is gradually making it's way into treatment algorithm of common cancers in India. We therefore would like to discuss in detail the updates in PET/CT imaging and radionuclide therapy and generate a consensus-driven evidence based document which would guide the practitioners of Oncology.

Predictive value of 18F-FDG PET/CT multi-metabolic parameters and tumor metabolic heterogeneity in the prognosis of gastric cancer

OBJECTIVE

We aimed to investigate the predictive value of pre-treatment 18F-FDG PET/CT multi-metabolic parameters and tumor metabolic heterogeneity for gastric cancer prognosis.

METHODS

Seventy-one patients with gastric cancer were included. All patients underwent 18F-FDG PET/CT whole-body scans prior to treatment and had pathologically confirmed gastric adenocarcinomas. Each metabolic parameter, including SUVmax, SUVmean, MTV, and TLG, was collected from the primary lesions of gastric cancer in all patients, and the slope of the linear regression between the MTV corresponding to different SUVmax thresholds (40% × SUVmax, 80% × SUVmax) of the primary lesions was calculated. The absolute value of the slope was regarded as the metabolic heterogeneity of the primary lesions, expressed as the heterogeneity index HI-1, and the coefficient of variance of the SUVmean of the primary lesions was regarded as HI-2. Patient prognosis was assessed by PFS and OS, and a nomogram of the prognostic prediction model was constructed, after which the clinical utility of the model was assessed using DCA.

RESULTS

A total of 71 patients with gastric cancer, including 57 (80.3%) males and 14 (19.7%) females, had a mean age of 61 ± 10 years; disease progression occurred in 27 (38.0%) patients and death occurred in 24 (33.8%) patients. Multivariate Cox regression analysis showed that HI-1 alone was a common independent risk factor for PFS (HR: 1.183; 95% CI: 1.010-1.387, P < 0.05) and OS (HR: 1.214; 95% CI: 1.016-1.450, P < 0.05) in patients with gastric cancer. A nomogram created based on the results of Cox regression analysis increased the net clinical benefit for patients. Considering disease progression as a positive event, patients were divided into low-, intermediate-, and high-risk groups, and Kaplan-Meier survival analysis showed that there were significant differences in PFS among the three groups. When death was considered a positive event and patients were included in the low- and high-risk groups, there were significant differences in OS between the two groups.

CONCLUSION

The heterogeneity index HI-1 of primary gastric cancer lesions is an independent risk factor for patient prognosis. A nomogram of prognostic prediction models constructed for each independent factor can increase the net clinical benefit and stratify the risk level of patients, providing a reference for guiding individualized patient treatment.

Prognostic value of [18F]FDG PET/CT on treatment response and progression-free survival of gastroesophageal cancer patients undergoing perioperative FLOT chemotherapy

PURPOSE

To evaluate the prognostic role of [¹⁸F]FDG PET/CT metabolic parameters in gastric cancer (GC) and gastroesophageal adenocarcinoma (GEJAC) patients receiving neoadjuvant chemotherapy.

METHOD

In this retrospective study, 31 patients with biopsy-proven GC or GEJAC were included between August 2016 and March 2020. [¹⁸F]FDG PET/CT was performed before the neoadjuvant chemotherapy. Primary tumours' semi-quantitative metabolic parameters were extracted. All patients received a perioperative FLOT regimen thereafter. Post-chemotherapy [¹⁸F]FDG PET/CT was performed in most patients (17/31). All patients underwent surgical resection. Histopathology response to treatment and progression-free survival (PFS) were evaluated. Two-sided p-values < 0.05 were considered statistically significant.

RESULTS

Thirty-one patients (mean age = 62 ± 8), including 21 GC and 10 GEJAC patients, were evaluated. 20/31(65%) patients were histopathology responders to neoadjuvant chemotherapy, including twelve complete and eight partial responders. During the median follow-up of 42.0 months, nine patients experienced recurrence. The median PFS was 60(95% CI:32.9-87.1) months. Pre-neoadjuvant chemotherapy SULpeak was significantly correlated with pathological response to treatment (p-value = 0.03;odds ratio = 16.75). In survival analysis, SUVmax (p-value = 0.01;hazard ratio[HR] = 1.55), SUVmean (p-value = 0.04;HR = 2.73), SULpeak (p-value < 0.001;HR = 1.91) and SULmean (p-value = 0.04;HR = 4.22) in the post-neoadjuvant chemotherapy pre-operative [¹⁸F]FDG PET/CT showed significant correlation with PFS. Additionally, aspects of staging were significantly correlated with PFS (p-value = 0.01;HR = 2.21).

CONCLUSIONS

Pre-neoadjuvant chemotherapy [¹⁸F]FDG PET/CT parameters, especially SULpeak, could predict the pathological response to treatment in GC and GEJAC patients. Additionally, in survival analysis, post-chemotherapy metabolic parameters significantly correlated with PFS. Thus, performing [¹⁸F]FDG PET/CT before chemotherapy may help to identify patients at risk for inadequate response to perioperative FLOT and, after chemotherapy, may predict clinical outcomes.

PET/CT for Predicting Occult Lymph Node Metastasis in Gastric Cancer

A portion of gastric cancer patients with negative lymph node metastasis at an early stage eventually die from tumor recurrence or advanced metastasis. Occult lymph node metastasis (OLNM] is a potential risk factor for the recurrence and metastasis in these patients, and it is highly important for clinical prognosis. Positron emission tomography (PET)/computed tomography (CT) is used to assess lymph node metastasis in gastric cancer due to its advantages in anatomical and functional imaging and non-invasive nature. Among the major metabolic parameters of PET, the maximum standardized uptake value (SUVmax) is commonly used for examining lymph node status. However, SUVmax is susceptible to interference by a variety of factors. In recent years, the exploration of new PET metabolic parameters, new PET imaging agents and radiomics, has become an active research topic. This paper aims to explore the feasibility and predict the effectiveness of using PET/CT to detect OLNM. The current landscape and future trends of primary metabolic parameters and new imaging agents of PET are reviewed. For gastric cancer patients, the possibility to detect OLNM non-invasively will help guide surgeons to choose the appropriate lymph node dissection area, thereby reducing unnecessary dissections and providing more reasonable, personalized and comprehensive treatments.

18F-FDG PET/CT-based radiomics nomogram for the preoperative prediction of lymph node metastasis in gastric cancer

Objective

Lymph node metastasis (LNM) is not only one of the important factors affecting the prognosis of gastric cancer but also an important basis for treatment decisions. The purpose of this study was to investigate the value of the radiomics nomogram based on preoperative ¹⁸F-deoxyglucose (FDG) PET/CT primary lesions and clinical risk factors for predicting LNM in gastric cancer (GC).

Methods

We retrospectively analyzed radiomics features of preoperative ¹⁸F-FDG PET/CT images in 224 gastric cancer patients from two centers. The prediction model was developed in the training cohort (n = 134) and validated in the internal (n = 59) and external validation cohorts (n = 31). The least absolute shrinkage and selection operator (LASSO) regression was used to select features and build radiomics signatures. The radiomics feature score (Rad-score) was calculated and established a radiomics signature. Multivariate logistic regression analysis was used to screen independent risk factors for LNM. The minimum Akaike’s information criterion (AIC) was used to select the optimal model parameters to construct a radiomics nomogram. The performance of the nomogram was assessed with calibration, discrimination, and clinical usefulness.

Results

There was no significant difference between the internal verification and external verification of the clinical data of patients (all p > 0.05). The areas under the curve (AUCs) (95% CI) for predicting LNM based on the ¹⁸F-FDG PET/CT radiomics signature in the training cohort, internal validation cohort, and external validation cohort were 0.792 (95% CI: 0.712–0.870), 0.803 (95% CI: 0.681–0.924), and 0.762 (95% CI: 0.579–0.945), respectively. Multivariate logistic regression showed that carbohydrate antigen (CA) 19-9 [OR (95% CI): 10.180 (1.267–81.831)], PET/CT diagnosis of LNM [OR (95% CI): 6.370 (2.256–17.984)], PET/CT Rad-score [OR (95% CI): 16.536 (5.506–49.660)] were independent influencing factors of LNM (all p < 0.05), and a radiomics nomogram was established based on those factors. The AUCs (95% CI) for predicting LNM were 0.861 (95% CI: 0.799–0.924), 0.889 (95% CI: 0.800–0.976), and 0.897 (95% CI: 0.683–0.948) in the training cohort, the internal validation cohort, and the external validation cohort, respectively. Decision curve analysis (DCA) indicated that the ¹⁸F-FDG PET/CT-based radiomics nomogram has good clinical utility.

Conclusions

Radiomics nomogram based on the primary tumor of ¹⁸F-FDG PET/CT could facilitate the preoperative individualized prediction of LNM, which is helpful for risk stratification in GC patients.

Predicting pathological response and overall survival in locally advanced gastric cancer patients undergoing neoadjuvant chemotherapy: the role of PET/computed tomography

BACKGROUND

Gastric cancer is the second leading cause of cancer-related deaths, with a 5-year survival rate of about 20-25%. The ability to predict pathological response (PR) to neoadjuvant chemotherapy (NACT); hence, overall survival (OS) probability of patients can allow the clinician to individualize treatment strategies. We investigated the role of F-18 fluorodeoxyglucose PET-computed tomography (F-18 FDG PET/CT) in predicting histopathologic response and prognosis in locally advanced gastric cancer (LAGC) patients undergoing NACT.

METHODS

F-18FDG PET/CT images taken before and after NACT, adenocarcinoma histopathology and operation pyesis reports of 43 LAGC patients were analyzed. Maximum (SUVmax) and mean (SUVmean) standardized uptake values, metabolic tumor volume (MTV), and total lesion glycolysis (TLG) of lesions were measured before and after NACT. Changes in percentage were calculated for ΔSUVmax%, ΔSUVmean%, ΔMTV%, ΔTLG%, and cutoff values were determined by receiver operating characteristic curve analysis. NACT response in pathology pyesis was determined according to the College of American Pathologists classification. PR and OS were analyzed with Kaplan-Meier and Cox proportional hazards regression models based on cutoffs found with PET measurements.

RESULTS

Cutoffs were ΔSUVmax = 33.31%, ΔSUVmean = 42.96%, ΔMTV = 30.38%, and ΔTLG = 28.14%, and all patients showed significance in PR and OS based on these cutoffs (all P < 0.01). PET/CT findings before and after NACT (ΔMTV > 30.38%, ΔTLG > 28.14%) predicted PR with 100% sensitivity and specificity. Multivariate analysis showed ΔSUVmean as an independent risk factor predicting OS (hazard ratio 0.348, 95% confidence interval 2.91-22.3, P = 0.03).

CONCLUSIONS

Metabolic parameters obtained with F-18 FDG PET/CT scanning before and after NACT in LAGC patients can accurately predict PR and OS.

Dynamic Changes in Pre- and Postoperative Levels of Inflammatory Markers and Their Effects on the Prognosis of Patients with Gastric Cancer

BACKGROUND

Whether the change of the pre- and postoperative systemic inflammatory response (SIR) levels will affect the prognosis of gastric cancer (GC) is unclear. We aimed to investigate the dynamic changes in the pre- and postoperative SIR and their prognostic value for GC.

METHODS

The clinicopathological data from 2257 patients who underwent radical gastrectomy between January 2009 and December 2014 at Fujian Medical University Union Hospital (FMUUH) were analyzed. Perioperative SIR changes were reported as changes in the lymphocyte-monocyte ratio (LMR), neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), and systemic immune-inflammation index (SII).

RESULTS

The SIR levels showed different trends from postoperative months 1 to 12. Multivariate analysis showed that preoperative (pre)-LMR was an independent predictor for the prognosis (P = 0.024). The postoperative 12-month (post-12-month) LMR predicted the 5-year overall survival (OS) rate with the highest accuracy (areas under the curve [AUC] 0.717). Patients were divided into four groups according to the optimal cutoff of the preoperative and post-12-month LMR: high pre-LMR to high postoperative (post)-LMR group, high pre-LMR to low post-LMR group, low pre-LMR to high post-LMR group, and low pre-LMR to low post-LMR group. The survival analysis showed 5-year OS rate was significantly higher in patients with high post-12-month LMR than in patients with low post-12-month LMR, regardless of pre-LMR levels (81.6% vs. 44.2%, P < 0.001). The prognostic accuracy was significantly improved by incorporating the post-12-month LMR in the tumor-node-metastasis (TNM) staging system (P = 0.003).

CONCLUSIONS

The remeasurement of LMR at post-12-month is helpful in predicting the long-term survival of GC.

Prognostic Value of Restaging F-18 Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography to Predict 3-Year Post-Recurrence Survival in Patients with Recurrent Gastric Cancer after Curative Resection

OBJECTIVE

The aim of this study was to investigate the prognostic value of the maximum standardized uptake value (SUV_max) measured while restaging with F-18 fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) to predict the 3-year post-recurrence survival (PRS) in patients with recurrent gastric cancer after curative surgical resection.

MATERIALS AND METHODS

In total, 47 patients with recurrent gastric cancer after curative resection who underwent restaging with ¹⁸F-FDG PET/CT were included. For the semiquantitative analysis, SUV_max was measured over the visually discernable ¹⁸F-FDG-avid recurrent lesions. Cox proportional-hazards regression models were used to predict the 3-year PRS. Differences in 3-year PRS were assessed with the Kaplan-Meier analysis.

RESULTS

Thirty-nine of the 47 patients (83%) expired within 3 years after recurrence in the median follow-up period of 30.3 months. In the multivariate analysis, SUV_max (p = 0.012), weight loss (p = 0.025), and neutrophil count (p = 0.006) were significant prognostic factors for 3-year PRS. The Kaplan-Meier curves demonstrated significantly poor 3-year PRS in patients with SUV_max > 5.1 than in those with SUV_max ≤ 5.1 (3-year PRS rate, 3.5% vs. 38.9%, p < 0.001).

CONCLUSION

High SUV_max on restaging with ¹⁸F-FDG PET/CT is a poor prognostic factor for 3-year PRS. It may strengthen the role of ¹⁸F-FDG PET/CT in further stratifying the prognosis of recurrent gastric cancer.

Intra-tumor metabolic heterogeneity of gastric cancer on 18F-FDG PETCT indicates patient survival outcomes

The present study aimed to investigate the prognostic value of intra-tumor metabolic heterogeneity on 2-[18F] Fluoro-2-deoxy-D-glucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) for patients with gastric cancer. Fifty-five patients with advanced gastric cancer that had received neoadjuvant chemotherapy and radical surgery were included. Clinicopathological information, ¹⁸F-FDG PET/CT before chemotherapy, pathological response, recurrence or metastasis, progression-free survival (PFS), and overall survival (OS) of the patients were collected. The maximum, peak, and mean standardized uptake values (SUV_max, SUV_peak, and SUV_mean), tumor-to-liver ratio (TLR), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) on PET/CT were measured. Heterogeneity index-1 (HI-1) was calculated as SUV_mean divided by the standard deviation, and heterogeneity index-2 (HI-2) was evaluated through linear regressions of MTVs according to different SUV thresholds. Associations between these parameters and patient survival outcomes were analyzed. None of the parameters on PET were associated with tumor recurrence. Pathological responders had significantly smaller TLR, MTV and HI-2 values than non-responders (P = 0.017, 0.017 and 0.013, respectively). In multivariate analysis of PFS, only HI-2 was an independent factor (hazard ratio [HR] = 2.693, P = 0.005) after adjusting for clinical tumor-node-metastasis (TNM) stage. In multivariate analysis of OS, HI-2 was also an independent predictive factor (HR = 2.281, P = 0.009) after adjusting for tumor recurrence. Thus, HI-2 generated from baseline ¹⁸F-FDG PET/CT is significantly associated with survival of patients with gastric cancer. Preoperative assessment of HI-2 by ¹⁸F-FDG PET/CT might be promising to identify patients with poor prognosis.

Prognostic Value of Metabolic Information in Advanced Gastric Cancer Using Preoperative 18F-FDG PET/CT

Purpose

This study evaluated the usefulness of semiquantitative and volumetric PET parameters for predicting prognosis in patients with advanced gastric cancer (AGC).

Methods

We enrolled 213 patients who underwent ¹⁸F-fluoro-2-deoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) prior to curative surgery for AGC. Maximum standardized uptake value (SUVmax) and tumor-to-liver uptake ratio (TLR) were measured in all patients. Metabolic tumor volume (MTV) and total lesion glycolysis were measured in volume-measurable patients. For further quantification of FDG uptake, we developed PET prognostic scores by combining SUVmax and MTV (1: low SUVmax/low MTV; 2: high SUVmax/low MTV; 3: high SUVmax/high MTV). Comparison of PET parameters between recurrence and non-recurrence groups was performed. Univariate and multivariate analyses for recurrence-free survival (RFS) and overall survival (OS) were subsequently performed.

Results

The recurrence rate was 32.4% (69/213 patients). Mean SUVmax and mean MTV of the recurrence group were significantly higher than those of the non-recurrence group (p = 0.026 and p = 0.025). TLR showed marginal significance (p = 0.051). In multivariate analysis for RFS including all patients, SUVmax (p = 0.022), TLR (p = 0.010), and PET score (p = 0.003) were independent prognostic factors. In post hoc analysis of PET score, significant differences in RFS were observed between PET scores 2 and 3 as well as scores 1 and 3. No significant difference in RFS was observed between scores 1 and 2. Only PET score was statistically significant for OS in univariate analysis. None of the PET parameters were statistically significant for OS in multivariate analysis.

Conclusion

High SUVmax and high MTV of the primary tumor suggest a high risk of recurrence for AGC patients. Even if SUVmax is similar, the prognosis may vary depending on MTV. Combining PET parameters results in a better prediction for prognosis.

A 18FDG PET/CT-based volume parameter is a predictor of overall survival in patients with local advanced gastric cancer

Objective

The present study investigated the prognosis value of preoperative fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in patients with local advanced gastric cancer (LAGC).

Methods

In total, 144 patients [median age 63 (range: 48−80) years old] with LAGC underwent¹⁸F-FDG PET/CT prior to any treatment. The maximum standardized uptake values (SUV_max), mean standardized uptake values (SUV_mean), metabolic tumor volume (MTV) and total lesion glycolysis (TLG) of the primary lesion were measured on PET/CT and correlated with clinicopathological features and survival.

Results

Significant differences in SUV_mean, SUV_max, MTV and TLG were found according to Lauren’s classification, histologic grade and T category (P<0.05). During the 26.5-month follow-up, 51 (35.4%) patients died and 70 (48.6%) exhibited disease progression. The optimal thresholds of MTV and TLG were 15.1 cm³ and 47.3 cm³, respectively. The 3-year progression-free survival (PFS) and overall survival (OS) for patients with high TLG values were 30% and 38% compared to 38% and 47% for low TLG values, respectively (P<0.05). Univariate and multifactor analyses demonstrated that lymph node metastasis and T stage were independent prognostic factors for PFS; T stage, histologic grade and TLG were independent prognostic factors for OS (P<0.05). Molecular markers had no relationship with patient’s outcomes.

Conclusions

Metabolic activity of primary gastric tumors from ¹⁸F-FDG PET/CT is a prognostic factor in patients with LAGC.

Volumetric parameters on 18F-FDG PET/CT predict the survival of patients with gastric cancer associated with their expression status of c-MET

Background

This study aimed to investigate the prognostic value of volumetric parameters on ¹⁸F- fluoro-2-deoxy-D-glucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) in gastric-cancer patients, according to the expression status of c-MET (MET proto-oncogene, receptor tyrosine kinase), which was previously unclear.

Methods

The study included 61 patients with advanced gastric cancer. Data on the baseline ¹⁸F-FDG PET/CT, clinical-pathological information, progression-free survival (PFS), and overall survival (OS) were collected. The maximum standardized uptake value (SUV_max), peak SUV (SUV_peak), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) of gastric tumors in situ were measured on PET/CT. The expression status of c-MET was recorded based on immunohistochemical staining. Associations between the parameters on PET/CT and patients’ survival outcomes were analyzed in relation to expression status of c-MET.

Results

Patients with positive c-MET expression had significantly shorter PFS (11.5 vs. 17.6 months, P = 0.039) and OS (17.0 vs. 24.3 months, P = 0.043), and had gastric tumors with a larger MTV (70.8 ± 53.11 vs. 41.1 ± 52.32, P = 0.034) and TLG (428.39 ± 442.95 vs. 205.7 ± 354.40, P = 0.039), compared with those with negative c-MET expression. However, SUV_max (9.6 ± 7.40 vs. 8.0 ± 4.91, P = 0.335) and SUV_peak (7.7 ± 5.99 vs. 6.62 ± 4.08, P = 0.438) were similar between these two patient groups. In patients with c-MET-positive tumors, MTV and TLG were independent factors in predicting patient OS after correction by distant metastasis (hazards ratio = 1.014 and 1.002, respectively; P = 0.024 and 0.027, respectively), while these associations were not significant in patients with c-MET-negative tumors.

Conclusions

Patients with c-MET-positive gastric cancer had higher MTV and TLG values compared to those with c-MET-negative gastric cancer. In patients with c-MET-positive gastric cancer, volumetric parameters on ¹⁸F-FDG PET/CT have prognostic value for patient overall survival.

Gastric cancer and image-derived quantitative parameters: Part 2-a critical review of DCE-MRI and 18F-FDG PET/CT findings

Abstract

There is yet no consensus on the application of functional imaging and qualitative image interpretation in the management of gastric cancer. In this second part, we will discuss the role of image-derived quantitative parameters from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) in gastric cancer, as both techniques have been shown to be promising and useful tools in the clinical decision making of this disease. We will focus on different aspects including aggressiveness assessment, staging and Lauren type discrimination, prognosis prediction and response evaluation. Although both the number of articles and the patients enrolled in the studies were rather small, there is evidence that quantitative parameters from DCE-MRI such as K^trans, V_e, K_ep and AUC could be promising image-derived surrogate parameters for the management of gastric cancer. Data from ¹⁸F-FDG PET/CT studies showed that standardised uptake value (SUV) is significantly associated with the aggressiveness, treatment response and prognosis of this disease. Along with the results from diffusion-weighted MRI and contrast-enhanced multidetector computed tomography presented in Part 1 of this critical review, there are additional image-derived quantitative parameters from DCE-MRI and ¹⁸F-FDG PET/CT that hold promise as effective tools in the diagnostic pathway of gastric cancer.

Key Points

• Quantitative analysis from DCE-MRI and¹⁸F-FDG PET/CT allows the extrapolation of multiple image-derived parameters.

• Data from DCE-MRI (K^trans, V_e, K_ep and AUC) and ¹⁸F-FDG PET/CT (SUV) are non-invasive, quantitative image-derived parameters that hold promise in the evaluation of the aggressiveness, treatment response and prognosis of gastric cancer.

Metabolic tumor burden on postsurgical PET/CT predicts survival of patients with gastric cancer

Background

The prognostic value of postoperative ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) to patients with gastric cancer remains unclear. This study aims to investigate the prognostic value of whole body (WB) metabolic tumor burden (MTB_WB) on postsurgical ¹⁸F-FDG PET/CT to patients with gastric cancer.

Methods

A total of 376 patients with surgeries-confirmed gastric cancer were enrolled. Clinicopathologic information, overall survival (OS) and MTB_WB parameters on postsurgical PET/CT, in terms of WB maximum standardized uptake value (SUV_WBmax), WB metabolic tumor volume (MTV_WB), and WB total lesion glycolysis (TLG_WB) were collected. In-between differences of patient clinicopathologic characteristics, OS and MTB_WB measurements were compared using chi-square test, Fisher’s exact test, Student’s t test or the Kaplan-Meier survival analysis. The optimal cutoffs of MTB_WB measurements were calculated through the receiver operating characteristic (ROC) curve analysis. Univariable and multivariable Cox proportional hazard regression were performed to test the predictive value of the clinicopathologic factors and MTB_WB measurements to patient survival.

Results

The PET-positive patients had significantly decreased OS based on either Kaplan-Meier survival analysis (P <  0.001) or univariable Cox regression (hazard ratio [HR] = 2.850, P <  0.001). In patients with PET-positive tumors, the associations between OS and SUV_WBmax, MTV_WB and TLG_WB were significant, both in univariable analysis (P <  0.001, P <  0.001 and P = 0.001, respectively) and in multivariable analysis (P = 0.002, P <  0.001 and P = 0.005, respectively). Patient OS among groups dichotomized by cutoffs of SUV_WBmax > 8.6, MTV_WB > 91.5 cm³, and TLG_WB > 477.6 cm³ were significantly different (P = 0.001, P <  0.001 and P = 0.001, respectively).

Conclusions

MTB_WB, in terms of SUV_WBmax, MTV_WB and TLG_WB, on postsurgical ¹⁸F-FDG PET/CT provides prognostic value to patients with gastric cancer after curative resection.

Preoperative Nodal 18F-FDG Avidity Rather than Primary Tumor Avidity Determines the Prognosis of Patients with Advanced Gastric Cancer

Purpose

This study investigated whether the metabolic avidity of primary tumors and/or metastatic lymph nodes (LNs) measured by ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) was related to survival after surgery in patients with advanced gastric cancer (AGC).

Materials and Methods

One hundred sixty-eight patients with AGC who underwent preoperative ¹⁸F-FDG PET/CT and curative resection were included. The ¹⁸F-FDG avidity of the primary gastric tumor and LNs was determined quantitatively and qualitatively. The diagnostic performance of ¹⁸F-FDG PET/CT was calculated, and the prognostic significance of ¹⁸F-FDG avidity for recurrence-free survival (RFS) and overall survival (OS) was assessed.

Results

In all, 51 (30.4%) patients experienced recurrence, and 32 (19.0%) died during follow-up (median follow-up duration, 35 months; range, 3-81 months); 119 (70.8%) and 33 (19.6%) patients showed ¹⁸F-FDG-avid primary tumors and LNs, respectively. ¹⁸F-FDG PET/CT showed high sensitivity (73.8%) for the detection of advanced pathologic T (pT ≥3) stage and high specificity (92.2%) for the detection of advanced pN (≥2) stage. ¹⁸F-FDG avidity of LNs was significantly associated with RFS (P=0.012), whereas that of primary tumors did not show significance (P=0.532). Univariate and multivariate analyses revealed that ¹⁸F-FDG avidity of LNs was an independent prognostic factor for RFS (hazard ratio=2.068; P=0.029).

Conclusions

¹⁸F-FDG avidity of LNs is an independent prognostic factor for predicting RFS. Preoperative ¹⁸F-FDG PET/CT can be used to determine the risk and prognosis of patients with AGC after curative resection.

Prognostic value of metabolic parameters on preoperative 18F-fluorodeoxyglucose positron emission tomography/ computed tomography in patients with stage III gastric cancer

This study investigated the prognostic value of metabolic parameters determined by 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in patients with stage III gastric cancer. Patients with pre-operative PET/CT and confirmed stage III after curative surgical resection were retrospectively enrolled. Parameters evaluated from pre-operative PET/CTwere maximum standardized uptake value (SUV_max) and peak SUV (SUV_peak) of primary tumor, SUV_max or SUV_peak of tumor to liver ratio (TLR_max and TLR_peak). Volumetric parameters, metabolic tumor volume (MTV) and total lesion glycolysis (TLG), were also evaluated. These PET/CT parameters were compared with the overall survival (OS) and recurrence-free survival (RFS). From total of 133 consecutive patients, tumor recurrence was found in 54 patients (40.6%) and 53 died during the follow-up period (median, 43 mo; range 5-62). In univariate analysis, SUV_max, SUV_peak, TLR_max and TLR_peak were significantly associated with the OS and RFS. In multivariate analysis, high TLR_max and TLR_peak were significantly unfavorable prognostic factors for RFS (both P<0.05) even after adjusting for age, depth of tumor invasion, lymph node metastasis, and chemotherapy. MTV and TLG showed no statistically significant correlation with outcome. In conclusion, glucose metabolism of primary tumor measured by pre-operative PET/CT provides prognostic information, especially for recurrence, in stage III gastric cancer.

Correlation Between Infection Status of Epstein-Barr Virus and 18F-Fluorodeoxyglucose Uptake in Patients with Advanced Gastric Cancer

BACKGROUND

Epstein-Barr virus-associated gastric cancer (EBVaGC) is one of the four molecular subtypes of gastric cancer, as defined by the classification recently proposed by The Cancer Genome Atlas. We evaluated the correlation between EBV positivity and ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) uptake by positron emission tomography/computed tomography (PET/CT) in patients with gastric cancer.

MATERIALS AND METHODS

We retrospectively enrolled patients with gastric cancer who underwent pretreatment ¹⁸F-FDG PET/CT and subsequent surgical resection, and then were diagnosed with advanced gastric cancer (pathologic stage ≥T2 with any N stage). Maximum standardized uptake values (SUV_max) of gastric cancer were measured by pretreatment ¹⁸F-FDG PET/CT. EBV sequences were detected by in situ hybridization (ISH) techniques. We analyzed the correlation between EBV positivity, clinicopathologic features and metabolic activity of the primary tumor.

RESULTS

A total of 205 patients were included and 15 (7.3%) patients were identified as having EBV-positive gastric cancer. Age, gender, tumor location, and histological type showed no significant differences between EBV-positive and negative groups. EBV-positive cancer is significantly more frequent in the higher-metabolic-tumor group than in the lower one (p=0.032). The mean SUV_max of gastric cancers showed significant differences between EBV-positive and negative groups (9.9±4.2 vs. 7.0±4.8, p=0.026).

CONCLUSION

The infection status of EBV was significantly related to the ¹⁸F-FDG uptake of primary tumors in patients with advanced gastric cancer.

Prognostic significance of interim 18 F-fluorodeoxyglucose positron emission tomography-computed tomography volumetric parameters in metastatic or recurrent gastric cancer

AIM

To evaluate the prognostic role of interim analysis of 18F-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET/CT) volumetric parameters in patients with recurrent or metastatic advanced gastric cancer (AGC) treated with fluoropyrimidine-based palliative chemotherapy.

METHODS

Forty-four patients who underwent baseline and interim PET/CT scanning during palliative chemotherapy were analyzed retrospectively. Initial and change of metabolic parameters (MP) - metabolic tumor volume (MTV), tumor lesion glycolysis (TLG) and maximum and mean standardized uptake values (SUV) were measured with PET/CT. Metabolic change was measured by ∆MP (%)  =  (MP_interim  - MP_initial )/MP _initial   ×  100. Independent t-test was employed to compare values of initial, interim and change of metabolic parameters between each response group. Log-rank test was employed for univariate analysis, and multivariate analysis was performed using the Cox proportional hazards regression model to determine independently significant prognostic factors.

RESULTS

Reduced percentage values of maximum and mean SUV on interim PET/CT and initial values of volumetric parameters (MTV and TLG) were significant predicting factors to response to fluoropyrimidine-based palliative chemotherapy. The decreased percentage values of metabolic parameters as well as maximum and mean SUV with receiver operating characteristic (ROC) curve determined cut-off points were significant prognostic factors for overall survival and progression-free survival in univariate and multivariate analyses.

CONCLUSION

Measurement of metabolic decrease of volumetric parameters by interim PET/CT analysis is useful to determine the prognosis of patients with recurrent or metastatic AGC.

PET/Computed Tomography and Precision Medicine: Gastric Cancer

Gastric cancer is a disease with low survival rates and high morbidity, requiring accurate and prompt diagnosis and treatment. Although limited in the evaluation of the primary tumor as such, the metabolic information of primary tumors in an ¹⁸F-FDG PET/CT study can assist in surgical and treatment planning and differentiating gastric cancers. It detects nodal disease with good specificity and positive predictive value, thus enabling appropriate therapy for individual patients. It provides valuable information about distant metastases, altering therapy decisions. It has reasonably good performance in detecting recurrent disease and in the follow-up of patients.

Prognostic value of pretreatment standardized uptake value of F-18-fluorodeoxyglucose PET in patients with gastric cancer: a meta-analysis

Background

F-18- fluorodeoxyglucose Positron emission tomography (¹⁸FDG-PET) has been widely used in clinical practice. However, the prognostic value of the pretreatment standardized uptake value (SUV) for patients with gastric cancer remains controversial.

Methods

Major databases were systematically searched. The quality of the included studies was assessed using the Newcastle–Ottawa scale; the PET protocols were also evaluated. The pooled hazard ratio (HR) for overall survival (OS) and recurrence-free survival (RFS) were used to estimate the effect size. Data from the included studies were analyzed using Review Manager Software version 5.2.

Results

Eight studies with 1080 patients were included. The pooled HR for OS of six studies including 672 patients was 1.72 (95% CI [1.28–2.3], p = 0.0004, I² = 0%), indicating that patients with high SUVs may have poor prognosis. The pooled HR for RFS was 1.70 (95% CI [1.20–2.39], p = 0.003, I² = 0%). Subgroup analysis based on the cutoff values determining method indicated that the receiver operating characteristic (ROC) method could better define the cutoff value. Subgroup analysis based on the therapeutic strategies used subsequently indicated the significant prognostic value of SUV.

Conclusion

In conclusion, our meta-analysis indicated that pretreatment SUV in primary lesions can be an important prognostic factor for overall survival and recurrence-free survival in patients with gastric cancer. High SUVs may indicate poor prognosis.

Predictive Role of the Number of 18F-FDG-Positive Lymph Nodes Detected by PET/CT for Pre-Treatment Evaluation of Locally Advanced Gastric Cancer

OBJECTIVES

The aim of this study was to investigate the predictive value of the numbers of metabolically positive lymph nodes (MPLN) detected by 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT) in patients with locally advanced gastric cancer (LAGC).

METHODS

We retrospectively analyzed the records of 50 patients with LAGC (stage T2-T4) who had undergone pre-operative PET/CT examination and laparotomy (total gastrectomy, n = 11; subtotal gastrectomy, n = 13; distal gastrectomy, n = 22; and bypass with gastrojejunstomy, n = 4). The numbers of MPLN were determined by combining visual observations with semi-quantitative measurements of the maximized standardized uptake value (SUVmax). Performance was investigated in terms of predicting post-surgical overall survival (OS).

RESULTS

The median post-surgical OS was 32.57 months (range 3.0-94 months). The numbers of MPLN were moderately correlated with the numbers of histological positive LN (r = 0.694, p = 0.001). In univariate analyses, the numbers of MPLN (≤ 2 vs. ≥3), PET/CT LN (positivity vs. negativity), SUVmax of LN (< 2.8 vs. ≥ 2.8), TNM stage (I, II vs. III, IV), and surgery type (R0 vs. non-R0) were significantly associated with OS. In multivariate analysis, surgery type (R0 vs. non-R0) and numbers of MPLN (≤ 2 vs. ≥ 3) were both independent factors for poor OS.

CONCLUSIONS

This explored study indicates that the number of MPLN could provide additional information for LAGC prognosis. Patients with MPLNs ≥ 3 may be at the risk of the more bad outcomes, and the further clinical trials are needed.

Correlation between PET-CT maximum standardized uptake value and HER2 expression in gastric carcinoma

AIM: To investigate the relationship between the maximum standardized uptake value (SUVmax) and human epidermal growth factor receptor 2 (HER2) expression in gastric carcinoma.

METHODS: Sixty-one patients who underwent PET-CT at our hospital and had pathologically proven gastric adenocarcinoma were included, and SUVmax was measured. HER2 expression was detected by immunohistochemistry. The correlation between SUVmax and HER2 expression was analyzed statistically.

RESULTS: Of all the patients, 28 were positive for HER2, with a positive rate of 49.12%. The SUVmax for the HER2 positive group was 4.6448 ± 3.18597, which was significantly higher than that for the HER2 negative group (P = 0.000). There was a moderate positive correlation between SUVmax and HER2, and the correlation coefficient was 0.581. According to the ROC analysis, the area under the curve of SUVmax was 0.83. Taking 5.800 as the threshold of SUVmax, the corresponding sensitivity and specificity were 82.1% and 79.8%, respectively.

CONCLUSION: There is a moderate correlation between SUVmax and HER2 in gastric adenocarcinoma, and SUVmax can help assess the biological characteristics of gastric cancer.

Prognostic significance of standardised uptake value (SUVmax ) measured on 18F-fluorodeoxyglucose positron emission tomography/computed tomography in patients with small cell lung cancer

Certain prognostic factors for small cell lung cancer (SCLC) have been validated, but the prognostic role of 18F-FDG PET/CT still remains unclear. The aim of this study was to evaluate the prognostic significance of 18F-FDG PET/CT in patients with SCLC. We reviewed 142 patients with pathologically proven SCLC who underwent pre-treatment 18F-FDG PET/CT. Standardised uptake value (SUV_max ) and other potential prognostic variables were chosen for analysis. The mean age of the study population was 58.2 ± 10.1 years (range, 25-84), and 124 (87.3%) patients were men. The median SUV_max value was 11.6 (4.0-29.3). Among the variables included in the univariate analysis, performance status (P = 0.001), disease stage (P < 0.001), administration of thoracic radiotherapy (TRT; P < 0.001), albumin level (P = 0.030) and LDH level (P < 0.001) showed prognostic significance. Further, multivariate analysis showed that performance status (P = 0.007), albumin level (P = 0.002), LDH level (P < 0.001) and administration of TRT (P = 0.001) were independent prognostic factors for survival. In conclusion, performance status, TRT, LDH level and albumin level were identified as important prognostic factors, while 18F-FDG PET/CT uptake of the primary lesions did not have any prognostic significance for survival in patients with SCLC.

Diagnostic performance of FDG PET/CT for surveillance in asymptomatic gastric cancer patients after curative surgical resection

PURPOSE

The present study evaluated the diagnostic performance of 2-[(18)F] fluoro-2-deoxy-D-glucose (FDG) positron emission tomography/computed tomography (PET/CT) for surveillance in asymptomatic gastric cancer patients after curative surgical resection.

METHODS

We retrospectively recruited 190 gastric cancer patients (115 early gastric cancer patients and 75 advanced gastric cancer patients) who underwent 1-year (91 patients) or 2-year (99 patients) postoperative FDG PET/CT surveillance, along with a routine follow-up program, after curative surgical resection. All enrolled patients were asymptomatic and showed no recurrence on follow-up examinations performed before PET/CT surveillance. All PET/CT images were visually assessed and all abnormal findings on follow-up examinations including FDG PET/CT were confirmed with histopathological diagnosis or clinical follow-up.

RESULTS

During follow-up, 19 patients (10.0 %) developed recurrence. FDG PET/CT showed abnormal findings in 37 patients (19.5 %). Among them, 16 patients (8.4 %) were diagnosed as cancer recurrence. Of 153 patients without abnormal findings on PET/CT, three patients were false-negative and diagnosed as recurrence on other follow-up examinations. The sensitivity, specificity, positive predictive value, and negative predictive value of FDG PET/CT were 84.2 %, 87.7 %, 43.2 %, and 98.0 %, respectively. Among 115 early gastric cancer patients, PET/CT detected recurrence in four patients (3.5 %) and one patient with local recurrence. Among 75 advanced gastric cancer patients, PET/CT detected recurrence in 12 patients (16.0 %), excluding two patients experiencing peritoneal recurrence. In addition, FDG PET/CT detected secondary primary cancer in six (3.2 %) out of all the patients.

CONCLUSIONS

Post-operative FDG PET/CT surveillance showed good diagnostic ability for detecting recurrence in gastric cancer patients. FDG PET/CT could be a useful follow-up modality for gastric cancer patients, especially those with advanced gastric cancer. However, further careful evaluation is needed because of false-positive findings on PET/CT.

Relationship Between 18F-FDG Uptake on PET and Recurrence Patterns After Curative Surgical Resection in Patients with Advanced Gastric Cancer

This study evaluated the predictive value of 18F-FDG PET for distant metastasis-free survival and peritoneal recurrence-free survival as well as recurrence-free survival and overall survival after curative surgical resection in patients with advanced gastric cancer (AGC).

METHODS

Two hundred seventy-nine patients with AGC who underwent preoperative 18F-FDG PET and subsequent curative surgical resection were included. The tumor-to-normal liver uptake ratio (TLR) of cancer lesions was measured, and the prognostic significance of TLR and tumor factors for distant metastasis-free survival, peritoneal recurrence-free survival, recurrence-free survival, and overall survival was assessed.

RESULTS

The 5-y recurrence-free survival, peritoneal recurrence-free survival, distant metastasis-free survival, and overall survival rates were 46.9%, 68.5%, 76.0%, and 58.1%, respectively. Depth of tumor invasion, lymph node metastasis, lymphovascular invasion, and TLR were independent prognostic factors for both recurrence-free survival and overall survival (P<0.05). For distant metastasis-free survival, lymphovascular invasion and TLR were independent risk factors (P<0.05). In patients with a TLR of 2.0 or less, the 5-y distant metastasis-free survival rate was 95.5%; in patients with a TLR greater than 2.0, the 5-y distant metastasis-free survival rate was 68.8%. For peritoneal recurrence-free survival, TLR showed no statistical significance (P=0.7) whereas pT stage, lymph node metastasis, Lauren classification, and Bormann type were independent prognostic factors (P<0.05).

CONCLUSION

18F-FDG uptake of AGC is an independent prognostic factor for distant metastasis-free survival, recurrence-free survival, and overall survival. The possibility of distant metastasis during follow-up should be considered in patients with high 18F-FDG uptake.

Preoperative Standardized Uptake Value of Metastatic Lymph Nodes Measured by 18F-FDG PET/CT Improves the Prediction of Prognosis in Gastric Cancer

This study assessed whether preoperative maximum standardized uptake value (SUVmax) of metastatic lymph nodes (LNs) measured by F-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (F-FDG PET/CT) could improve the prediction of prognosis in gastric cancer.One hundred fifty-one patients with gastric cancer and pathologically confirmed LN involvement who had undergone preoperative F-FDG PET/CT prior to curative surgical resection were retrospectively enrolled. To obtain nodal SUVmax, a transaxial image representing the highest F-FDG uptake was carefully selected, and a region of interest was manually drawn on the highest F-FDG accumulating LN. Conventional prognostic parameters and PET findings (primary tumor and nodal SUVmax) were analyzed for prediction of recurrence-free survival (RFS) and overall survival (OS). Furthermore, prognostic accuracy of survival models was assessed using c-statistics.Of the 151 patients, 38 (25%) experienced recurrence and 34 (23%) died during follow-up (median follow-up, 48 months; range, 5-74 months). Twenty-seven patients (18%) showed positive F-FDG nodal uptake (range, 2.0-22.6). In these 27 patients, a receiver-operating characteristic curve demonstrated a nodal SUVmax of 2.8 to be the optimal cutoff for predicting RFS and OS. The univariate and multivariate analyses showed that nodal SUVmax (hazard ratio [HR] = 2.71, P < 0.0001), pathologic N (pN) stage (HR = 2.58, P = 0.0058), and pathologic T (pT) stage (HR = 1.77, P = 0.0191) were independent prognostic factors for RFS. Also, nodal SUVmax (HR = 2.80, P < 0.0001) and pN stage (HR = 2.28, P = 0.0222) were independent prognostic factors for OS. A predictive survival model incorporating conventional risk factors (pT/pN stage) gave a c-statistic of 0.833 for RFS and 0.827 for OS, whereas a model combination of nodal SUVmax with pT/pN stage gave a c-statistic of 0.871 for RFS (P = 0.0355) and 0.877 for OS (P = 0.0313).Nodal SUVmax measured by preoperative F-FDG PET/CT is an independent prognostic factor for RFS and OS. Combining nodal SUVmax with pT/pN staging can improve survival prediction precision in patients with gastric cancer.

18F-FDG PET/CT role in staging of gastric carcinomas: comparison with conventional contrast enhancement computed tomography

The purpose of the report was to evaluate the role of fluorine-18 fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (F-FDG PET/CT) in staging gastric cancer comparing it with contrast enhancement computed tomography (CECT).This retrospective study included 45 patients who underwent performed whole body CECT and F-FDG PET/CT before any treatment. We calculated CECT and F-FDG PET/CT sensitivity, specificity, accuracy, positive and negative predictive values (PPV and NPV) for gastric, lymphnode, and distant localizations; furthermore, we compared the 2 techniques by McNemar test. The role of F-FDG PET/CT semiquantitative parameters in relation to histotype, grading, and site of gastric lesions were evaluated by ANOVA test.Sensitivity, specificity, accuracy, PPV and NPV of CECT, and F-FDG PET/CT for gastric lesion were, respectively, 92.11%, 57.14%, 86.66%, 92.11%, 57.14% and 81.58%, 85.71%, 82.22%, 96.88%, 46.15%. No differences were identified between the 2 techniques about sensitivity and specificity. No statistical differences were observed between PET parameters and histotype, grading, and site of gastric lesion. The results of CECT and F-FDG PET/CT about lymphnode involvement were 70.83%, 61.90%, 66.66%, 68%, 65% and 58.33%, 95.24%, 75.55%, 93.33%, 66.67%. The results of CECT and F-FDG PET/CT about distant metastases were 80%, 62.86%, 66.66%, 38.10%, 91.67% and 60%, 88.57%, 82.22%, 60%, 88.57%. FDG PET/CT specificity was significantly higher both for lymphnode and distant metastases.The F-FDG PET/CT is a useful tool for the evaluation of gastric carcinoma to detect primary lesion, lymphnode, and distant metastases using 1 single image whole-body technique. Integration of CECT with F-FDG PET/CT permits a more valid staging in these patients.

Use of Imaging for GI Cancers

GI cancers are a heterogeneous group of neoplasms that differ in their biologic and physical behaviors depending on the organ of origin, location within the organ, and degree of differentiation. As a result, evaluation of these tumors is complex, requiring integration of information from a patient's clinical history, physical examination, laboratory data, and imaging. With advances in anatomic and functional imaging techniques, we now have tools for assessing patients with these tumors at diagnosis, staging, and treatment assessment. It is difficult for a single imaging modality to provide all the necessary information for a given GI tumor. However, well-chosen combinations of available imaging modalities based on the indications, strength, and limitations of the modalities will provide optimal evaluation of patients with these malignancies.