The Predictive and Prognostic Value of Early Metabolic Response Assessed by Positron Emission Tomography in Advanced Gastric Cancer Treated with Chemotherapy

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.

Predictive Value of Preoperative Endoscopic Ultrasound (EUS) After Neoadjuvant Chemotherapy in Locally Advanced Esophagogastric Cancer - Data From a Randomized German Phase II Trial

PURPOSE

The role of EUS before or after neoadjuvant chemotherapy (nCTX) in advanced esophagogastric cancer (EGC) is still unclear. The phase II NEOPECX trial evaluated perioperative chemotherapy with or without panitumumab in this setting. The aim of this sub-study was to investigate the prognostic value of EUS-guided preoperative staging before and after nCTX.

MATERIALS AND METHODS

Preoperative yuT/yuN stages by EUS were compared with histopathological ypT/ypN stages after curative resection. Reduction in T-stage from baseline to preoperative EUS was defined as downstaging (DS+) and compared to progression-free (PFS) and overall survival (OS) of patients without downstaging (DS-). In addition, preoperative EUS N-stages (positive N+ or negative N-) were correlated with clinical data.

RESULTS

The preoperative yuT-stage correlated with the ypT-stage in 48% of cases (sensitivity 48%, specificity 52%), while the preoperative yuN-stage correlated with the ypN-stage in 64% (sensitivity 76%, specificity 52%). Within DS+ patients who were downstaged by ≥ 2 T-categories, a trend towards improved OS was detected (median OS DS+: not reached (NR), median OS DS-: 38.5 months (M), p=0.21). Patients with yuN+ at preoperative EUS had a worse outcome than yuN- patients (median OS yuN-: NR, median OS yuN+: 38.5 M, p = 0.013).

CONCLUSION

The diagnostic accuracy of EUS to predict the response after nCTX in patients with advanced EGC is limited. In the current study the endosonographic detection of lymph node metastasis after nCTX indicates a poor prognosis. In the future, preoperative EUS with sectional imaging procedures may be used to tailor treatment for patients with advanced EGC.

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.

Three-year outcomes of the randomized phase III SEIPLUS trial of extensive intraoperative peritoneal lavage for locally advanced gastric cancer

Whether extensive intraoperative peritoneal lavage (EIPL) after gastrectomy is beneficial to patients with locally advanced gastric cancer (AGC) is not clear. This phase 3, multicenter, parallel-group, prospective randomized study (NCT02745509) recruits patients between April 2016 and November 2017. Eligible patients who had been histologically proven AGC with T3/4NxM0 stage are randomly assigned (1:1) to either surgery alone or surgery plus EIPL. The results of the two groups are analyzed in the intent-to-treat population. A total of 662 patients with AGC (329 patients in the surgery alone group, and 333 in the surgery plus EIPL group) are included in the study. The primary endpoint is 3-year overall survival (OS). The secondary endpoints include 3-year disease free survival (DFS), 3-year peritoneal recurrence-free survival (reported in this manuscript) and 30-day postoperative complication and mortality (previously reported). The trial meets pre-specified endpoints. Estimated 3-year OS rates are 68.5% in the surgery alone group and 70.6% in the surgery plus EIPL group (log-rank p = 0.77). 3-year DFS rates are 61.2% in the surgery alone group and 66.0% in the surgery plus EIPL group (log-rank p = 0.24). The pattern of disease recurrence is similar in the two groups. In conclusion, EIPL does not improve the 3-year survival rate in AGC patients.

A Metabolic-associated Nomogram Predicts Recurrence Survival of Thyroid Cancer

OBJECTIVE

Various studies have suggested that metabolic genes play a significant role in papillary thyroid cancer (PTC). The current study aimed to identify a metabolic signature related biomarker to predict the prognosis of patients with PTC.

METHODS

We conducted a comprehensive analysis on the data obtained from the Cancer Genome Atlas (TCGA) database. The correlation between survival result and metabolic genes was evaluated based on the univariate Cox analyses, least absolute shrinkage and selection operator (LASSO) and multivariate Cox analyses. The performance of a 7-gene signature was assessed according to Kaplan-Meier and receiver operating characteristic (ROC) analysis. Multivariate Cox regression analysis was adopted to unearth clinical factors related to the recurrence free survival (RFS) of patients with PTC. Finally, a prognostic nomogram was developed based on risk score, cancer status and cancer width to improve the prediction for RFS of PTC patients.

RESULTS

Seven metabolic genes were used to establish the prognostic model. The ROC curve and C-index exhibited high value in training, testing and the whole TCGA datasets. The established nomogram, incorporating the 7-metabolic gene signature and clinical factors, was able to predict the RFS with high effectiveness. The 7-metabolic gene signature-based nomogram had a good performance to predict the RFS of patients with PTC.

CONCLUSION

Our study identified a 7-metabolic gene signature and established a prognostic nomogram, which were useful in predicting the RFS of PTC.

AKP and GGT level can provide an early prediction of first-line treatment efficacy in colorectal cancer patients with hepatic metastases

Aim: It is important to early evaluate or predict the efficacy to avoid ineffective treatment for most colorectal cancer (CRC) patients with liver metastases. Patients & methods: The medical records of 440 patients with histologically confirmed primary CRC admitted to the Fudan University Shanghai Cancer Center were reviewed. Results: High baseline serum alkaline phosphatase (AKP) and γ-glutamyl transferase (GGT) is associated with worse overall survival. In patients with a high serum AKP and GGT a decreased percentage had high objective response rate and better progression-free survival. Conclusion: Measuring the changes of serum AKP or GGT in CRC patients with hepatic metastases before and after the first cycle of treatment is a convenient, fast and economical way to early predict antitumor treatment efficacy.

Prospective evaluation of metabolic intratumoral heterogeneity in patients with advanced gastric cancer receiving palliative chemotherapy

Although metabolic intratumoral heterogeneity (ITH) gives important value on treatment responses and prognoses, its association with treatment outcomes have not been reported in gastric cancer (GC). We aimed to evaluate temporal changes in metabolic ITH and the associations with treatment responses, progression-free survival (PFS), and overall survival (OS) in advanced GC patients. Eighty-five patients with unresectable, locally advanced, or metastatic GC were prospectively enrolled before the first-line palliative chemotherapy and underwent [¹⁸F]FDG PET at baseline (TP1) and the first response follow-up evaluation (TP2). Standardized uptake values (SUVs), volumetric parameters, and textural features were evaluated in primary gastric tumor at TP1 and TP2. Of 85 patients, 44 had partial response, 33 had stable disease, and 8 progressed. From TP1 to TP2, metabolic ITH was significantly reduced (P < 0.01), and the degree of the decrease was greater in responders than in non-responders (P < 0.01). Using multiple Cox regression analyses, a low SUV_max at TP2, a high kurtosis at TP2 and larger decreases in the coefficient of variance were associated with better PFS. A low SUV_max at TP2, larger decreases in the metabolic tumor volume and larger decreased in the energy were associated with better OS. Age older than 60 years and responders also showed better OS. An early reduction in metabolic ITH is useful to predict treatment outcomes in advanced GC patients.

GPER1 Silencing Suppresses the Proliferation, Migration, and Invasion of Gastric Cancer Cells by Inhibiting PI3K/AKT-Mediated EMT

G protein coupled estrogen receptor (GPER1) is a membrane estrogen receptor, belonging to the seven-transmembrane G protein-coupled receptors family, and has important biological functions in cancer. However, the functional role of GPER1 in gastric cancer (GC) remain incompletely understood. In the present study, we employed gene set enrichment analysis and discovered that GPER1 expression was concomitant with EMT process and was positively correlated with activation of the PI3K/AKT pathway in GC. Knockdown of GPER1 with siRNA suppressed the proliferation, migration, and invasion of AGS and MGC-803 GC cells. Knockdown of GPER1 also downregulated the mesenchymal markers N-cadherin and vimentin, upregulated E-cadherin, an epithelial marker, and suppressed expression of the Snail, Slug and Twist1 transcription factors, indicating that knockdown of GPER1 inhibited EMT. Moreover, 740Y-P, a PI3K activator, reversed the effects of GPER1 knockdown on EMT processes. Overexpression of GPER1 with plasmid can further prove these findings. In summary, these data demonstrate that GPER1 inhibition suppresses the proliferation, migration, and invasion of gastric cancer cells by inhibiting PI3K/AKT-mediated EMT. Our study elucidated the function of GPER1 in gastric cancer, and we identified PI3K/AKT-mediated EMT as a novel mechanism by which GPER1 contributes to proliferation, migration, and invasion of gastric cancer. These data suggest that combining inhibition of GPER1 and PI3K may be a potential therapeutic approach to inhibit gastric cancer metastasis.

Volumetric parameters derived from FLT-PET performed at completion of treatment predict efficacy of Carbon-ion Radiotherapy in patients with locally recurrent Nasopharyngeal Carcinoma

The purpose of this study was to investigate the role of 3'-deoxy-3'-[¹⁸F]fluorothymidine (FLT)-PET for predicting the outcome of patients with locally recurrent nasopharyngeal carcinoma (LR-NPC) treated by carbon-ion radiotherapy (CIRT). Patients received FLT-PET/CT scan one-week prior to or after completion of CIRT were enrolled in the study. All patients were from prospective trials or treated using a standardized protocol. Time-dependent receiver operator characteristics (ROC) were used to determine the optimal cutoff values for FLT-PET parameters. Univariable and multivariable analyses of local progression-free survival (LPFS) were performed using Cox regression, to examine the prognostic value of FLT-PET parameters, including SUV_max, metabolic tumor volume (MTV) and total lesion thymidine (TLT). A total of 41 patients were enrolled. Elevated MTV and TLT were significantly associated with worse LPFS, in both univariable and multivariable analyses. ROC analysis revealed that both an MTV value higher than 8.6 and a TLT value higher than 14.9 were predictive of increased risk of developing local recurrence, the adjusted HRs were 5.59 (p=0.009) and 7.76 (p=0.002), respectively. In conclusion, FLT-PET was found to be a promising prognostic tool for LR-NPC patients and might play a role in the treatment guidance.

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.

Chinese consensus on the diagnosis and treatment of gastric cancer with liver metastases

Background

The incidence of gastric cancer with liver metastases (GCLM) is 9.9-18.7%, with a median survival time of 11 months and a 5-year survival rate <20%. Multidisciplinary treatment (MDT) is gradually gaining recognition as the most important method. However, specific treatment plans remain unclear. The aim of study was to provide a consensus to improve the diagnosis and treatment of GCLM.

Methods

We brought together experts from relevant medical fields across China, including the Chinese Research Hospital Association Digestive Tumor Committee, Chinese Association of Upper Gastrointestinal Surgeons, Chinese Gastric Cancer Association, and the Gastrointestinal Surgical Group of Chinese Surgical Society Affiliated to Chinese Medical Association, to discuss and formulate this consensus.

Results

A consensus was reached on the diagnosis and treatment of GCLM. Moreover, we have developed a new clinical classification system, the Chinese Type for Gastric Cancer Liver Metastases, based on the likelihood of a surgical treatment being successful.

Conclusions

The MDT mode should be implemented throughout all treatment of GCLM.A Chinese version of this expert consensus has been published in the Chinese Journal of Practical Surgery (Volume 39, Issue 10, p. 405-411). Written permission was obtained from the Chinese Journal of Practical Surgery to disseminate the expert consensus in English.

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.

The Diagnostic and Prognostic Value of Digital Rectal Examination in Gastric Cancer Patients with Peritoneal Metastasis

Background: Peritoneal metastasis (PM) is the most common cause of death in gastric cancer (GC) patients. However, diagnosis of PM is still difficult in clinical practice. This study aimed to explore the diagnostic and prognostic value of digital rectal examination (DRE) in GC. Methods: 247 GC patients with PM confirmed by operation were included. The diagnostic yield of DRE compared with computed tomography (CT) was calculated. In another group of 1330 cases receiving radical gastrectomy, 38 cases with DRE (+) postoperatively were analyzed to identify risk factors. A nomogram was constructed to predict postoperative DRE (+). Results: The specificity, positive predictive value and positive likelihood ratio of DRE in diagnosis of PM was 99.8%, 91.2% and 58.4, higher than CT (97.6%, 64.9% and 10.4). Though the sensitivity of DRE (12.6%) was lower than CT (24.7%), 17 of 31 patients with DRE (+) could not be found by CT. Moreover, the overall survival of confirmed PM patients with DRE (+) (PM-DRE (+)) was much lower than PM-DRE (-) patients (P<0.001). In addition, the nomogram to predict postoperative DRE (+) had a bootstrap-corrected concordance index of 0.73 and was well calibrated. Conclusions: GC patients with DRE (+) could be regarded as a special subtype of stage IV ones with poorer prognosis. Supply of palliative care and chemotherapy rather than unnecessary operation might be a better alternative for these patients. DRE was an effective supplement for CT and should be generally recommended for GC patients.

Scoring System for Tumor-Infiltrating Lymphocytes and Its Prognostic Value for Gastric Cancer

The tumor microenvironment (TME) is the internal environment of malignant tumor progression, and the host antitumor immune response and normal tissue destruction occur in the TME. Tumor-infiltrating lymphocytes (TIL) is a crucial component of the TME and reflect the host antitumor immune response. The purpose of this study was to discuss the methodology for TIL evaluation and assess the prognostic value of TIL in gastric cancer. In total, we reviewed 1,033 gastrectomy cases between 2002 and 2008 at the Third Affiliated Hospital of Soochow University. To understand the prognostic value of TIL in gastric cancer (GC), TIL were assessed by optical microscopy, and verified by immunohistochemistry. There is no current consensus on TIL scoring in GC. In this study, we discussed a TIL evaluation system that includes an analysis of the amount and percentage of TIL in a tumor. Ultimately, 439 (52.7%) cases showed high levels of TIL and 394 (47.3%) cases had low levels. There was a statistically significant relationship among TIL, tumor size, histological grade, LN metastasis, nerve invasion, tumor thrombus, pTN stage, and WHO subtypes (p < 0.001, respectively). TIL^hi was a positive significant predictor of overall survival (OS) in Kaplan-Meier survival analysis (P < 0.001) and multivariate Cox regression analysis (HR = 0.431, 95% CI: 0.347-0.534, P < 0.001). After surgery, patients with malignant tumors underwent chemoradiotherapy according to standard therapeutic guidelines based on TNM stage. The TNM scoring system cannot reflect the full information of TME; therefore, TIL can be used as a diagnostic supplement. We constructed a nomogram model that showed more predictive accuracy for OS than pTN stage. In summary, this study proves that high levels of TIL are associated with a positive prognosis and that TIL reflect the protective host antitumor immune response.

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.

Current clinical status of 18F-FLT PET or PET/CT in digestive and abdominal organ oncology

Positron emission tomography (PET) or PET/computed tomography (CT) using ¹⁸F-3'-fluoro-3'-deoxythymidine (¹⁸F-FLT) offers noninvasive assessment of cell proliferation in human cancers in vivo. The present review discusses the current status on clinical applications of ¹⁸F-FLT-PET (or PET/CT) in digestive and abdominal oncology by comparing with ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG)-PET (or PET/CT). The results of this review show that although ¹⁸F-FLT uptake is lower in most cases of digestive and abdominal malignancies compared with ¹⁸F-FDG uptake, ¹⁸F-FLT-PET can be used to detect primary tumors. ¹⁸F-FLT-PET has shown greater specificity for N staging than ¹⁸F-FDG-PET which can show false-positive uptake in areas of inflammation. However, because of the high background uptake in the liver and bone marrow, it has a limited role of assessing liver and bone metastases. Instead, ¹⁸F-FLT-PET will be a powerful tool for monitoring response to treatment and provide prognostic information in digestive and abdominal oncology.

Sanguinarine inhibits growth and invasion of gastric cancer cells via regulation of the DUSP4/ERK pathway

Sanguinarine, a bioactive benzophenanthridine alkaloid extracted from plants of the Papaveraceae family, has shown antitumour effects in multiple cancer cells. But the therapeutic effects and regulatory mechanisms of sanguinatine in gastric cancer (GC) remain elusive. This study was aimed to investigate the correlation of dual‐specificity phosphatase 4 (DUSP4) expression with clinicopathologic features and overall survival in patients with GC and explore the effects of sanguinarine on tumour growth and invasion in GC cells (SGC‐7901 and HGC‐27) and underlying molecular mechanisms. Immunohistochemical analysis showed that decreased DUSP4 expression was associated with the sex, tumour size, depth of invasion and distant metastasis in patients with GC. Functional experiments including CCK‐8, Transwell and flow cytometry analysis indicated that sanguinarine or DUSP4 overexpression inhibited GC cell viability and invasive potential, and induced cell apoptosis and cycle arrest in S phase, but DUSP4 knockdown attenuated the antitumour activity of sanguinarine. Further observation demonstrated that sanguinarine up‐regulated the expression of DUSP4 and Bcl‐2‐associated X protein (Bax), but down‐regulated phosphorylated extracellular signal‐regulated kinase (p‐ERK), proliferating cell nuclear antigen (PCNA), matrix metalloproteinase 2 (MMP‐2) and B‐cell lymphoma 2 (Bcl‐2) expression. Taken together, our findings indicate that sanguinarine inhibits growth and invasion of GC cells through regulation of the DUSP4/ERK pathway, suggesting that sanguinarine may have potential for use in GC treatment.

Evaluation of 18F-fluorothymidine positron emission tomography ([18F]FLT-PET/CT) methodology in assessing early response to chemotherapy in patients with gastro-oesophageal cancer

BACKGROUND

3'-Deoxy-3'-[18F]fluorothymidine ([18F]FLT) PET has limited utility in abdominal imaging due to high physiological hepatic uptake of a tracer. We evaluated [18F]FLT-PET/CT combined with a temporal-intensity information-based voxel-clustering approach termed kinetic spatial filtering (KSF) to improve tumour visualisation in patients with locally advanced and metastatic gastro-oesophageal cancer and as a marker of early response to chemotherapy. Dynamic [18F]FLT-PET/CT data were collected before and 3 weeks post first cycle of chemotherapy. Changes in tumour [18F]FLT-PET/CT variables were determined. Response was determined on contrast-enhanced CT after three cycles of therapy using RECIST 1.1.

RESULTS

Ten patients were included. Following application of the KSF, visual distinction of all oesophageal and/or gastric tumours was observed in [18F]FLT-PET images. Among the nine patients available for response evaluation (RECIST 1.1), three patients had responded (partial response) and six patients were non-responders (stable disease). There was a significant association between Ki-67 and all baseline [18F]FLT-PET parameters. Area under the curve (AUC) from 0 to 1 min was associated with treatment response.

CONCLUSIONS

The results of this study indicate that application of the KSF allowed accurate visualisation of both primary and metastatic lesions following imaging with the proliferation marker, [18F]FLT-PET/CT. However, [18F]FLT-PET uptake parameters did not correlate with response. Instead, we observe significant changes in tracer delivery following chemotherapy suggesting that further [18F]FLT-PET/CT studies in this tumour type should be undertaken with caution.