Value of Preoperative PET-CT in the Prediction of Pathological Stage of Gastric Cancer

Nuclear medicine based multimodal molecular imaging facilitates precision medicine for gastrointestinal tumors

Gastric and colorectal cancers are the most common gastrointestinal malignancies, with high morbidity and mortality rates. Early diagnosis and accurate staging are of great significance for formulating reasonable clinical treatment plans, guiding surgical methods, effectively carrying out individualized comprehensive treatment, and estimating prognosis. As representatives of nuclear medicine based multimodal molecular imaging technologies, positron emission tomography/computed tomography and positron emission tomography/magnetic resonance imaging allow for obtaining the status of lesions throughout the body in one imaging procedure, and are less likely to miss distant and neighboring metastatic lesions. It is very important to truly achieve accurate disease classification and diagnosis, and develop individualized disease prevention and treatment plans. The emerging multimodal nuclide tracer molecular imaging technology has important clinical value in the diagnosis and treatment of gastric cancer and colorectal cancer. This article reviews the application and progress of the two examination methods in the diagnosis and staging of gastric cancer and colorectal cancer.

Staging accuracy in patients with clinical T2N0 gastric cancer: Implications for treatment sequencing

BACKGROUND

Patients with clinical T2N0 (cT2N0) gastric adenocarcinoma are recommended to undergo either perioperative chemotherapy or upfront resection. If T2N0 disease is pathologically confirmed, patients may be observed without chemotherapy. These guidelines create the possibility of both systemic therapy overuse and underuse depending on clinical staging accuracy. Our objectives were to define factors associated with upstaging after upfront resection and describe the association between postoperative chemotherapy and survival.

METHODS

Patients with cT2N0 gastric adenocarcinoma were identified using the National Cancer Database. Factors associated with upstaging were assessed by logistic regression. Survival was assessed using Kaplan-Meier and Cox proportional hazard analyses.

RESULTS

Of 4,076 patients undergoing upfront resection for cT2N0 gastric cancer, 1,933 (47.4%) were pathologically upstaged. Patients were more likely to be upstaged if they had >3.0-cm (adjusted odds ratio [aOR] 2.31, 95% confidence interval [CI] 1.97-2.70; P < .001) or poorly differentiated tumors (aOR 2.22, 95% CI 1.89-2.60; P < .001). Patients were less likely to be upstaged if they had distal tumors (aOR 0.77, 95% CI 0.64-0.93; P = .006). Of those pathologically upstaged (n = 1,933), 1,111 (57.4%) received adjuvant chemotherapy that was associated with improved survival (HR 0.55, 95% CI 0.47-0.63; P < .001). Among those not upstaged (n = 2,143), 247 (11.5%) received adjuvant chemotherapy that was not associated with improved survival (HR 0.92, 95% CI 0.70-1.21; P = .54).

CONCLUSIONS

Pathologic upstaging after upfront resection in patients with cT2N0 gastric cancer is associated with patient and tumor characteristics. Adjuvant chemotherapy is associated with improved survival only in the patients upstaged at surgery. An upfront surgical approach may be preferred in select patients, especially if avoiding chemotherapy is desired.

Improving individualised therapies in localised gastro-oesophageal adenocarcinoma

Despite our increased understanding of the biological and molecular aspects of gastro-oesophageal tumourigenesis, the identification of prognostic or predictive factors remains challenging. Patients with resectable gastric and oesophageal adenocarcinoma are often treated similarly after surgical resection, regardless of their tumour biology, clinical characteristics, and histological treatment response. Substantial progress has been made in the past 5 years in managing patients with gastric or oesophageal adenocarcinoma, including the use of immune checkpoint inhibitors and new targeted therapies, leading to substantial improvements in clinical outcomes. These advancements have primarily been established in advanced and metastatic disease, while the management framework for local and locoregional disease is just beginning to shift. We provide an overview of existing data on biomarkers and tumour-related and host-related factors that are relevant to stratify patients into low-risk and high-risk recurrence groups, both before and after surgery, paving the way for more personalised treatment approaches.

Incremental value of PET primary lesion-based radiomics signature to conventional metabolic parameters and traditional risk factors for preoperative prediction of lymph node metastases in gastric cancer

BACKGROUND

Precise preoperative prediction of lymph node metastasis (LNM) is crucial for optimal diagnosis and treatment in patients with gastric cancer (GC), in which existing imaging methods have certain limitations. We hypothesized that PET primary lesion-based radiomics signature could provide incremental value to conventional metabolic parameters and traditional risk indicators in predicting LNM in patients with GC.

METHODS

This retrospective study was performed in 127 patients with GC who underwent preoperative PET/CT. Basic clinical data and PET conventional metabolic parameters were collected. Radiomics signature was constructed by the least absolute shrinkage and selection operator algorithm (LASSO) logistic regression. Based on the postoperative histological results, the patients were divided into LNM group and non-lymph node metastasis (NLNM) group. Receiver-operating characteristic (ROC) was used to evaluate the discriminatory ability of Radiomics score (Rad-score) for predicting LNM and determine whether adding Rad-score to PET conventional metabolic parameters and traditional risk factors could improve the predictive value in LNM. The Integrated discrimination improvement (IDI) and net reclassification improvement (NRI) were calculated to further confirm the incremental value of Rad-score for predicting LNM in GC.

RESULTS

The LNM group had higher Rad-score than NLNM group [(0.35 (-0.13-0.85) vs. -0.61 (-1.92-0.18), P < 0 .001)]. After adjusted for gender, age, BMI, and FBG, multivariable logistic regression analysis illustrated that Rad-score (OR: 6.38, 95% CI: 2.73-14.91, P < 0.0001) was independent risk factors for LNM in GC. Adding PET conventional parameters to traditional risk factors increased the predictive value of LNM in GC (AUC 0.751 vs 0.651, P = 0.02). Additional inclusion of Rad-score to conventional metabolic parameters and traditional risk indicators significantly improved the AUC (0.882 vs 0.751; P = 0.006). Bootstrap resampling (times = 500) was used for internal verification, 95% confidence interval (CI) was 0.802-0.948, with the sensitivity equaled to 89.5%, and positive predictive value (PPV) was 93.5%. When Rad-score was added to conventional metabolic parameters and traditional risk indicators, net reclassification improvement (NRI) was 0.293 (P = 0.0040) and integrated discrimination improvement (IDI) was 0.293 (P = 0.0045).

CONCLUSION

In GC patients, PET Radiomics signature of the primary lesion-based was significantly associated with LNM and could improve the prediction of LNM above PET conventional metabolic parameters and traditional risk factors, which could provide incremental value for individual diagnosis and treatment of GC.

Korean Practice Guidelines for Gastric Cancer 2022: An Evidence-based, Multidisciplinary Approach

Gastric cancer is one of the most common cancers in Korea and the world. Since 2004, this is the 4th gastric cancer guideline published in Korea which is the revised version of previous evidence-based approach in 2018. Current guideline is a collaborative work of the interdisciplinary working group including experts in the field of gastric surgery, gastroenterology, endoscopy, medical oncology, abdominal radiology, pathology, nuclear medicine, radiation oncology and guideline development methodology. Total of 33 key questions were updated or proposed after a collaborative review by the working group and 40 statements were developed according to the systematic review using the MEDLINE, Embase, Cochrane Library and KoreaMed database. The level of evidence and the grading of recommendations were categorized according to the Grading of Recommendations, Assessment, Development and Evaluation proposition. Evidence level, benefit, harm, and clinical applicability was considered as the significant factors for recommendation. The working group reviewed recommendations and discussed for consensus. In the earlier part, general consideration discusses screening, diagnosis and staging of endoscopy, pathology, radiology, and nuclear medicine. Flowchart is depicted with statements which is supported by meta-analysis and references. Since clinical trial and systematic review was not suitable for postoperative oncologic and nutritional follow-up, working group agreed to conduct a nationwide survey investigating the clinical practice of all tertiary or general hospitals in Korea. The purpose of this survey was to provide baseline information on follow up. Herein we present a multidisciplinary-evidence based gastric cancer guideline.

Prognostic value of the metabolic score obtained via [18F]FDG PET/CT and a new prognostic staging system for gastric cancer

We developed and validated a new staging system that includes metabolic information from pretreatment [¹⁸F]Fluorodeoxyglucose ([¹⁸F]FDG) positron emission tomography/computed tomography (PET/CT) for predicting disease-specific survival (DSS) in gastric cancer (GC) patients. Overall, 731 GC patients undergoing preoperative [¹⁸F]FDG PET/CT were enrolled and divided into the training (n = 543) and validation (n = 188) cohorts. A metabolic score (MS) was developed by combining the maximum standardized uptake value (SUVmax) of the primary tumor (T_SUVmax) and metastatic lymph node (N_SUVmax). A new staging system incorporating the MS and tumor-node-metastasis (TNM) stage was developed using conditional inference tree analysis. The MS was stratified as follows: score 1 (T_SUVmax ≤ 4.5 and N_SUVmax ≤ 1.9), score 2 (T_SUVmax > 4.5 and N_SUVmax ≤ 1.9), score 3 (T_SUVmax ≤ 4.5 and N_SUVmax > 1.9), and score 4 (T_SUVmax > 4.5 and N_SUVmax > 1.9) in the training cohort. The new staging system yielded five risk categories: category I (TNM I, II and MS 1), category II (TNM I, II and MS 2), category III (TNM I, II and MS ≥ 3), category IV (TNM III, IV and MS ≤ 3), and category V (TNM III, IV and MS 4) in the training cohort. DSS differed significantly between both staging systems; the new staging system showed better prognostic performance in both training and validation cohorts. The MS was an independent prognostic factor for DSS, and discriminatory power of the new staging system for DSS was better than that of the conventional TNM staging system alone.

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.

Superiority of [68Ga]Ga-FAPI-04/[18F]FAPI-42 PET/CT to [18F]FDG PET/CT in delineating the primary tumor and peritoneal metastasis in initial gastric cancer

OBJECTIVE

This study aimed to compare [⁶⁸Ga]Ga-FAPI-04/[¹⁸F]FAPI-42 PET/CT with [¹⁸F]FDG PET/CT in the evaluation of initial gastric cancer.

METHODS

We retrospectively compared [⁶⁸Ga]Ga-FAPI-04/[¹⁸F]FAPI-42 PET/CT with [¹⁸F]FDG PET/CT in patients with initial gastric cancer from September 2020 to March 2021. Lesion detectability and the uptake of lesions quantified by the maximum standardized uptake value (SUVmax) and target-to-background ratio (TBR) were compared between the two modalities using the Wilcoxon signed-rank test, Mann-Whitney U test, and McNemar's chi-square test.

RESULTS

A total of 61 patients (37 males, aged 23-81 years) were included, of which 22 underwent radical gastrectomy. For primary lesions, higher uptake of [⁶⁸Ga]Ga-FAPI-04/[¹⁸F]FAPI-42 was observed compared to [¹⁸F]FDG (median SUVmax, 14.60 vs 4.35, p < 0.001), resulting in higher positive detection using [⁶⁸Ga]Ga-FAPI-04/[¹⁸F]FAPI-42 PET/CT than [¹⁸F]FDG PET/CT (95.1% vs 73.8%, p < 0.001), particularly for tumors with signet-ring cell carcinoma (SRCC) (96.4% vs 57.1%, p < 0.001). [⁶⁸Ga]Ga-FAPI-04/[¹⁸F]FAPI-42 PET/CT detected more positive lymph nodes than [¹⁸F]FDG PET/CT (637 vs 407). However, both modalities underestimated N staging compared to pathological N staging. [⁶⁸Ga]Ga-FAPI-04/[¹⁸F]FAPI-42 PET/CT showed a higher sensitivity (92.3% vs 53.8%, p = 0.002) and peritoneal cancer index score (18 vs 3, p < 0.001) in peritoneum metastasis and other suspect metastases compared to [¹⁸F]FDG PET/CT.

CONCLUSION

Our findings indicate that [⁶⁸Ga]Ga-FAPI-04/[¹⁸F]FAPI-42 PET/CT outperformed [¹⁸F]FDG PET/CT in the evaluation of primary tumors with SRCC and peritoneum metastasis in initial gastric cancer. However, no clinically useful improvement was seen in N staging.

KEY POINTS

• The uptake of [⁶⁸Ga]Ga-FAPI-04/[¹⁸F]FAPI-42 in primary tumor and metastasis was intensely higher than that of [¹⁸F]FDG (p < 0.001) in 61 patients with initial gastric cancer. • [⁶⁸Ga]Ga-FAPI-04/[¹⁸F]FAPI-42 PET/CT had a higher sensitivity detection in primary tumors (95.1% vs 73.8%, p < 0.001) and peritoneal metastases (92.3% vs 53.8%, p = 0.002) than [¹⁸F]FDG PET/CT. • [⁶⁸Ga]Ga-FAPI-04/[¹⁸F]FAPI-42 PET/CT depicted more positive lymph nodes than [¹⁸F]FDG PET/CT (637 vs 407); however, both underestimated N staging compared to pathological N staging.

Preoperative prediction of the pathological stage of advanced gastric cancer by 18F-fluoro-2-deoxyglucose positron emission tomography

In recent years, the usefulness of neoadjuvant chemotherapy for resectable advanced gastric cancer, particularly stage III, has been reported. Preoperative staging is mainly determined by computed tomography (CT), and the usefulness of ¹⁸F-fluoro-2-deoxyglucose positron emission tomography/CT (FDG-PET/CT) for gastric cancer has been limited in usefulness. The study aimed to evaluate the usefulness of FDG-PET/CT in preoperative diagnosis of advanced gastric cancer. We retrospectively enrolled 113 patients with gastric cancer who underwent preoperative FDG-PET/CT. All patients underwent gastrectomy with lymph-node dissection. The maximum standardized uptake value (SUVmax) of the primary tumor (T-SUVmax) and lymph nodes (N-SUVmax) were measured for all patients. The cutoff values of T-SUVmax for pathological T3/4 from receiver operating characteristic analysis were 8.28 for differentiated and 4.32 for undifferentiated types. The T-SUVmax and N-SUVmax cutoff values for pathological lymph-node metastasis were 4.32 and 1.82, respectively. Multivariate analysis showed that T-SUVmax for differentiated types was a significant predictor of pathological T3/4, and N-SUVmax was a significant predictor of lymph-node metastasis. In conclusion, the SUVmax of FDG-PET/CT was a useful predictor of pathological T3/4 and lymph-node metastasis in gastric cancer. The diagnosis by preoperative FDG-PET/CT is promising to contribute a more accurate staging of gastric cancer than by CT scan alone.

Role of Positron Emission Tomography/Computed Tomography in Gastrointestinal Malignancies: A Brief Review and Pictorial Essay

Positron emission tomography/computed tomography (PET/CT) is increasingly becoming a mainstay in diagnosis and management of many malignant disorders. However, its role in the assessment of gastro-intestinal lesions is still evolving. The aim of this review was to demonstrate the areas, where PET/CT is impactful and where it has limitations. This will allow for us to reduce unnecessary investigations and develop methods to overcome the limitations.

Association between neutrophil-lymphocyte ratio and lymph node metastasis in gastric cancer: A meta-analysis

INTRODUCTION AND AIM

The prognostic role of neutrophil to lymphocyte ratio (NLR) has been explored extensively in the literature. The aim of this meta-analysis was to evaluate the link between NLR and lymph node metastasis in gastric cancer. A method for increasing specificity and sensitivity of pre-treatment staging has implications on treatment algorithms and survival.

SEARCH STRATEGY

The relevant databases were searched as per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses flowchart. After selection, 12 full text articles that met the inclusion criteria were included for quantitative analysis. 2 × 2 squares were generated using lymph node positive/negative, and NLR high/low data. The effect size for each study was calculated using the DerSimonian-Laird random effects model. P values were calculated using the chi-square method. Finally publication bias was evaluated. All statistics were calculated using R Studio.

RESULTS

Meta-analysis showed a 1.90 times (odds ratio, with 95% CI 1.52-2.38) increase in risk of positive lymph node status with high neutrophil to lymphocyte ratio. This has significant implications for cancer screening and staging, as NLR is a highly reproducible, cost-effective, and widely available prognostic factor for gastric cancer patients. Additionally, high or low NLR values may have implications for management pathways. Patients with lymph node metastasis can be offered neoadjuvant chemotherapy, avoiding salvage therapy in the form of adjuvant chemoradiotherapy, which is poorly tolerated.

CONCLUSION

This meta-analysis shows an association between NLR and positive lymph node status in gastric cancer patients with implications for staging, as well as preoperative personalisation of therapy.

Development and Validation of Multivariate Models Integrating Preoperative Clinicopathological Parameters and Radiographic Findings Based on Late Arterial Phase CT Images for Predicting Lymph Node Metastasis in Gastric Cancer

RATIONALE AND OBJECTIVES

To develop and validate multivariate models integrating endoscopic biopsy, tumor markers, computed tomography (CT) morphological characteristics based on late arterial phase (LAP), and CT value-related and texture parameters to predict lymph node (LN) metastasis in gastric cancers (GCs).

MATERIALS AND METHODS

The preoperative differentiation degree based on biopsy, 6 tumor markers, 8 CT morphological characteristics based on LAP, 18 CT value-related parameters, and 35 CT texture parameters of 163 patients (111 men and 52 women) with GC were analyzed retrospectively. The differences in parameters between N (-) and N (+) GCs were analyzed by the Mann-Whitney U test. Diagnostic performance was obtained by receiver operating characteristic (ROC) curve analysis. Multivariate models based on regression analysis and machine learning algorithms were performed to improve diagnostic efficacy.

RESULTS

The differentiation degree, carbohydrate antigen (CA) 199 and CA242, 5 CT morphological characteristics, and 22 CT texture parameters showed significant differences between N (-) and N (+) GCs in the primary cohort (all p < 0.05). The multivariate model integrating clinicopathological parameters and radiographic findings based on regression analysis achieved areas under the ROC curve (AUCs) of 0.936 and 0.912 in the primary and validation cohorts, respectively. The model generated by the support vector machine algorithm achieved AUCs of 0.914 and 0.948, respectively.

CONCLUSION

We developed and validated multivariate models integrating endoscopic biopsy, tumor markers, CT morphological characteristics based on LAP, and CT texture parameters to predict LN metastasis in GCs and achieved satisfactory performance.

Preoperative Staging Diagnosis of Colorectal Cancer Based on Multi-Row Spiral CT

Colorectal cancer is a common malignant tumor of digestive tract, and its incidence has increased significantly in recent years. The 5-year survival rate of patients with early local colorectal cancer is more than 90%, with local invasion of about 68%, and distant metastasis of less than 10%. Therefore, early diagnosis and early treatment is an effective means for the prevention and treatment of colorectal cancer. At present, X-ray air-barium double contrast radiography and fiberoptic endoscope are most commonly used in the examination of colorectal tumors in the world. These two methods have the advantages of simple operation, intuition and low cost. However, it is limited to judge the depth of tumor invasion, whether to break through the serosa, lymphatic metastasis, and distant metastasis. In this work, it can be confirmed that the measurement of preoperative tumor vascular volume reconstruction density is feasible in the preoperative evaluation of colorectal cancer, it will provide clinicians with more valuable information about preoperative tumor staging. Besides, multi-slice spiral CT has the advantages of less trauma, high speed, and clear image. It can not only judge the location of the tumor, the depth, and extent of tumor invasion, and show distant organ metastasis, but also has good application value in tumor staging. In this paper, the clinical data and MSCT imaging data of patients with colorectal cancer were analyzed retrospectively, and the value of MSCT in the diagnosis of colorectal cancer was discussed.

Accuracy of 18F-FDG PET/CT and CECT for primary staging and diagnosis of recurrent gastric cancer: A meta-analysis

Contrast-enhanced computed tomography (CECT) is commonly used for staging and diagnosing recurrent gastric cancer. Recently, 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET)/CT gained popularity as a diagnostic tool owing to advantages including dual functional and anatomical imaging, which may facilitate early diagnosis. The diagnostic performance of 18F-FDG PET/CT and CECT has been assessed in several studies but with variable results. Therefore, the present meta-analysis aimed to evaluate the accuracy of 18F-FDG PET/CT and CECT for primary TNM staging and the diagnosis of recurrent gastric cancers. A systematic search of the PubMed Central, Medline, Scopus, Cochrane and Embase databases from inception until January 2020 was performed. The Quality Assessment of Diagnostic Accuracy Study-2 tool was used to determine the quality of the selected studies. Pooled estimates of sensitivity and specificity were calculated. A total of 58 studies comprising 9,997 patients were included. Most studies had a low risk of bias. The sensitivity and specificity for nodal staging of gastric cancer were 49% (95% CI, 37-61%) and 92% (95% CI, 86-96%) for 18F-FDG PET/CT, respectively, and 67% (95% CI, 57-76%) and 86% (95% CI, 81-89%) for CECT, respectively. For metastasis staging, the sensitivity and specificity were 56% (95% CI, 40-71%) and 97% (95% CI, 87-99%) for 18F-FDG PET/CT, respectively, and 59% (95% CI, 41-75%) and 96% (95% CI, 83-99%) for CECT, respectively. For diagnosing cancer recurrence, the pooled sensitivity and specificity were 81% (95% CI, 72-88%) and 83% (95% CI, 74-89%) for 18F-FDG PET/CT, respectively, and 59% (95% CI, 41-75%) and 96% (95% CI, 83-99%) for CECT, respectively. Both 18F-FDG PET/CT and CECT were deemed highly useful for diagnosing recurrent gastric cancer due to their high sensitivities and specificities. However, these techniques cannot be used to exclude or confirm the presence of lymph node metastases or recurrent gastric cancer tumors, but can be used for the confirmation of distal metastasis.

An Immune-Related Gene Panel for Preoperative Lymph Node Status Evaluation in Advanced Gastric Cancer

Background and Aim: Gastric cancer (GC) is the common leading cause of cancer-related death worldwide. Immune-related genes (IRGs) may potentially predict lymph node metastasis (LNM). We aimed to develop a preoperative model to predict LNM based on these IRGs. Methods: In this paper, we compared and evaluated three machine learning models to predict LNM based on publicly available gene expression data from TCGA-STAD. The Pearson correlation coefficient (PCC) method was utilized to feature selection according to its relationships with LN status. The performance of the model was assessed using the area under the curve (AUC) and F1 score. Results: The Naive Bayesian model showed better performance and was constructed based on 26 selected gene features, with AUCs of 0.741 in the training set and 0.688 in the test set. The F1 score in the training set and test set was 0.652 and 0.597, respectively. Furthermore, Naive Bayesian model based on 26 IRGs is the first diagnostic tool for the identification of LNM in advanced GC. Conclusion: These results indicate that our new methods have the value of auxiliary diagnosis with promising clinical potential.

Improving MR sequence of 18F-FDG PET/MR for diagnosing and staging gastric Cancer: a comparison study to 18F-FDG PET/CT

Purpose

Evaluate the feasibility of fluorine-18 (¹⁸F) fluorodeoxyglucose (FDG) positron emission tomography (PET) and magnetic resonance (MR) imaging in patients with gastric cancer by optimizing the scan protocol and to compare the image quality to ¹⁸F FDG PET and computed tomography (CT).

Methods

The PET/CT and PET/MR imaging were sequentially performed in 30 patients with gastric cancer diagnosed by gastroscope using a single-injection-with-dual-imaging protocol. After intravenous injection of ¹⁸F-FDG (mean, 249 MBq), PET/CT imaging including low-dose CT was performed (mean uptake time, 47 ± 6 min), and PET/MR imaging including a T1-weighted Dixon sequence for attenuation correction and two different T2-weighted sequences was subsequently acquired (88 ± 15 min after ¹⁸F-FDG injection). Four series of images (CT from PET/CT, T1W, T2W Half-Fourier acquisition single-shot turbo spin-echo [T2W-HASTE] and T2W-BLADE from PET/MR) were visually evaluated using a 3–4 points scale for: (1) image artifacts, (2) lesion conspicuity and (3) image fusion quality. The characteristics of the primary lesions were assessed and compared between the PET/CT and PET/MR acquisitions.

Results

The image quality and lesion conspicuity of the T2W-HASTE images were significantly improved compared to that of the T2W-BLADE images. A significantly higher number of artifacts were seen in the T2W-HASTE images compared with the T1W and CT images (p < 0. 05). No differences in the accuracy of image fusion between PET/MR and PET/CT (p > 0. 05); however, significant difference was seen in the lesion conspicuity measurements (p < 0.05) with T2W-HASTE being superior. For information about the primary lesion characteristics, the T2W-HASTE images provided the most successful identifications compared with those of the T1W and PET/CT (13vs7vs5) images.

Conclusions

PET/MR with the T2W-HASTE was better at revealing the details of local stomach lesions compared with PET/CT imaging. Combining the PET/MR with the T2W-HASTE technique is a promising imaging method for diagnosing and staging gastric cancer.

The significance of preoperative serum carcinoembryonic antigen levels in the prediction of lymph node metastasis and prognosis in locally advanced gastric cancer: a retrospective analysis

Background

In this study, we aimed to investigate the preoperative serum carcinoembryonic antigen (CEA) in the diagnosis of positive lymph node metastasis (LNM), and to evaluated the relationship between CEA and survival in patients with locally advanced gastric cancer (LAGC).

Methods

The significance of the preoperative serum CEA level for the diagnose of LAGC and prediction of LNM was determined using the receiver operating characteristic (ROC) curve. The areas under the ROC of CEA were compared with those of other tumor markers or imaging examination including CT and MRI. Logistic regression was utilized to identify the risk factors predicting positive LNM. Independent prognosis factors were evaluated using univariate and multivariate COX regression analyses.

Results

The ROC curves showed that the AUCs of CEA, CA199, and CA125 for diagnosing LAGC were 0.727, 0.594, and 0.566. When used to predict LNM, the AUC of CEA, CA199 and CA125 were 0.696, 0.531, and 0.588. Logistic regression analysis demonstrated that preoperative serum CEA were significantly associated with positive LNM. On combining imaging examination with CEA, the sensitivity and specificity were 85.3 and 79.4%, respectively, with the AUC equal to 0.853. The combination of CEA and imaging examination preformed the highest levels of AUC and sensitivity for diagnosing LNM, which is significantly higher than using either of them alone. Although patients with abnormal CEA have a poor prognosis, two models of multivariate analysis showed that CEA was not the independent prognosis factor for survival.

Conclusions

CEA can be used to diagnose gastric cancer and determine whether it has LNM. Moreover, combined with CEA could improve the diagnostic sensitivity of imaging examination for lymph node involvement.

Staging FDG PET-CT changes management in patients with gastric adenocarcinoma who are eligible for radical treatment

AIM

18-fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET-CT) is valuable in the management of patients with oesophageal cancer, but a role in gastric cancer staging is debated. Our aim was to review the role of FDG PET-CT in a large gastric cancer cohort in a tertiary UK centre.

METHODS

We retrospectively reviewed data from 330 patients presenting with gastric adenocarcinoma between March 2014 and December 2016 of whom 105 underwent pre-treatment staging FDG PET-CT scans. FDG PET-CT scans were graded qualitatively and quantitatively (SUVmax) and compared with staging diagnostic CT and operative pathology results (n = 30) in those undergoing resection.

RESULTS

Of the 105 patients (74 M, median age 73 years) 86% of primary tumours were metabolically active (uptake greater than normal stomach) on FDG PET-CT [41/44 (93%) of the intestinal histological subtype (SUVmax 14.1 ± 1.3) compared to 36/46 (78%) of non-intestinal types (SUVmax 9.0 ± 0.9), p = 0.005]. FDG PET-CT upstaged nodal or metastastic staging of 20 patients (19%; 13 intestinal, 6 non-intestinal, 1 not reported), with 17 showing distant metastases not evident on other imaging. On histological analysis, available in 30 patients, FDG PET-CT showed low sensitivity (40%) but higher specificity (73%) for nodal involvement.

CONCLUSION

FDG PET-CT provides new information in a clinically useful proportion of patients, which leads to changes in treatment strategy, most frequently by detecting previously unidentified metastases, particularly in those with intestinal-type tumours.

Clinical significance of neutrophil-to-lymphocyte ratio as a predictor of lymph node metastasis in gastric cancer

Background

Precise staging is indispensable to select the appropriate treatment strategy for gastric cancer (GC); however, the diagnostic accuracy of conventional modalities needs to be improved. This study investigated the clinical significance of the preoperative neutrophil-to-lymphocyte ratio (NLR) for the prediction of pathological lymph node metastasis (pN+) in GC.

Methods

This was a retrospective study of 429 patients with GC who underwent curative gastrectomy. The predictive ability of NLR for pN+ was examined in comparison with that of computed tomography.

Results

The preoperative NLR ranged from 0.6 to 10.8 (median, 2.0), and the optimal cut-off value for predicting pN+ was 1.6 according to the receiver operating characteristic curve with the maximal Youden index. Multivariate analysis identified a NLR ≥ 1.6 (odds ratio (OR) 3.171; 95% confidence interval (CI) 1.448–7.235, p = 0.004) and cN+ (OR 2.426; 95% CI 1.221–4.958, p = 0.011) to be independent factors associated with pN+ in advanced GC (cT2-T4). On the other hand, a NLR ≥ 1.6 was not useful for predicting pN+ in early GC (cT1). In advanced GC, a NLR ≥ 1.6 detected pN+ with a higher sensitivity (84.9%) and negative predictive value (NPV) (63.9%) than conventional modalities (50.0 and 51.7%, respectively). When the subjects were limited to those with advanced GC with cN0, the sensitivity and NPV of a NLR ≥ 1.6 for pN+ increased further (90.7 and 81.0%, respectively).

Conclusion

The preoperative NLR may be a useful complementary diagnostic tool for predicting pN+ in advanced GC because of its higher sensitivity and NPV than conventional modalities.

Application value of MRI diffuse weighted imaging combined with PET/CT in the diagnosis of stomach cancer at different stages

Value of MRI diffusion-weighted imaging (MRI DWI) combined with PET/CT in the diagnosis and staging of stomach cancer (SC) was investigated. A retrospective analysis was performed on 160 patients with SC diagnosed by pathological biopsy in The Affiliated Yantai Yuhuangding Hospital of Qingdao University from March 2015 to April 2018. The values of MRI DWI, PET/CT and combined diagnosis in the diagnosis and staging of SC were compared according to the criteria of diagnosis of postoperative pathological or clinical comprehensive evaluation. The sensitivity, specificity and diagnostic coincidence rate of MRI DWI in the diagnosis of SC at stage I-II were 61.05, 64.62 and 62.50%, respectively, which were significantly lower than those of PET/CT (P<0.05). Sensitivity, specificity and diagnostic coincidence rate of MRI DWI in the diagnosis of SC at stage III-IV were lower than those of PET/CT (P<0.05). Sensitivity and diagnostic coincidence rate of MRI DWI combined with PET/CT in the diagnosis of SC at stage I-II were significantly higher than those of MRI DWI or PET/CT alone (P<0.05). Specificity and diagnostic coincidence rate of MRI DWI combined with PET/CT in the diagnosis of SC at stage III-IV were significantly higher than those of MRI DWI or PET/CT alone (P<0.05). PET/CT is superior to MRI DWI in SC staging, whereas the diagnostic efficiency of combined scan is much higher than that of PET/CT or MRI DWI alone. In order to obtain more accurate preoperative staging and to avoid diagnostic exploratory laparotomy, the combination of MRI DWI and PET/CT techniques should be used in the comprehensive analysis of the disease to improve the accuracy of clinical diagnosis.

The long-term prognostic difference between gastrectomy with and without preoperative chemotherapy in patients with clinical stage IV gastric cancer

BACKGROUND/OBJECTIVE

The role of gastrectomy for stage IV gastric cancer (GC) has not yet been established. Thus, we aimed to compare the prognoses of patients with clinical stage IV GC who underwent gastrectomy with and without preoperative chemotherapy after precise recategorization of patients.

METHODS

We retrospectively reviewed a total of 92 clinical stage IV GC patients who underwent gastrectomy with or without preoperative chemotherapy between 2010 and 2016 at a single institution. Yoshida's classification was used to categorize the patients into the following categories: 1, technically resectable metastasis; 2, marginally resectable metastasis; 3, unresectable peritoneal dissemination; and 4, incurable peritoneal dissemination with distant organ metastasis. Two-year disease-specific survival (DSS) rates were compared between patients who underwent primary surgery and preoperative chemotherapy for each category.

RESULTS

The two-year DSS rates of primary surgery vs. preoperative chemotherapy in Categories 1, 2, 3, and 4 (n = 35, 39, 14, and 4, respectively) were 48.6% vs. 41.7% (p = 0.829), 52.6% vs. 40.0% (p = 0.855), 50.0% vs. 75.0% (p = 0.027), and 0% vs. 66.7% (p = 0.083), respectively. Patients in Categories 1 and 2 who underwent preoperative chemotherapy tended to have lower two-year DSS rates (p = 0.911), whereas patients in Categories 3 and 4 had significantly higher two-year DSS rates than those who underwent primary surgery (p = 0.014).

CONCLUSIONS

Primary surgery may be performed in patients without peritoneal dissemination when GC is technically resectable. However, if peritoneal dissemination is suspected, chemotherapy should be prioritized.

The expression of the insulin receptor in gastric cancer correlates with the HER2 status and may have putative therapeutic implications

BACKGROUND

Metabolic reprogramming in gastric cancer (GC) involves not only an alteration of glucose metabolism, but also of insulin receptor (IR) expression. We investigated if (1) GCs express the IR in cancer cells (CC-IR) and vasculature (VIR), (2) IR expression is clinically relevant and may be a novel target of GC treatment.

METHODS

467 primary GCs were studied by immunohistochemistry using an IR-specific antibody. CD31-immunostaining ensured the presence of representative intratumoral microvasculature. VIR, and membranous and cytoplasmic CC-IR (mCC-IR, cCC-IR) were evaluated using a modified HistoScore (HScore) and subsequently dichotomized into low or high IR expressions. The IR status was correlated with clinico-pathological patient characteristics, including survival and HER2 status.

RESULTS

VIR, mCC-IR, and cCC-IR (HScore > 0) were found in 97.0%, 87.6%, and 95.7% of all GCs. After dichotomization of the HScores, 50.7, 48.8, and 50.3% were classified as VIR-high, mCC-IR-high, and cCC-IR-high, respectively. IR was associated with the Laurén phenotype, tumor localization, local tumor growth, vascular invasion, perineural invasion, tumor budding, mucin phenotype, UICC stage, worse survival, and the HER2 status. On multivariate analysis, VIR status was an independent prognosticator of overall (p = 0.010) and tumor-specific (p = 0.006) patient survival.

CONCLUSIONS

VIR and CC-IR expressions are frequent in GC, biologically significant and even correlate with the HER2 status, opening avenues for novel putative therapeutic interventions in GC.

[Multivisceral resection with and without HIPEC in cancer surgery]

BACKGROUND

Multivisceral resections seem to be naturally associated with an elevated morbidity rate. Data regarding the impact of multivisceral resections on progression-free and overall survival are only available in insufficient quantities.

OBJECTIVE

Data on multivisceral resections in cancer surgery are presented exemplified by gastric cancer, colorectal cancer and peritoneal metastases, focusing on overall and progression-free survival as well as morbidity and mortality.

MATERIAL AND METHODS

A PubMed search was carried out including the following terms: multivisceral resection, peritoneal metastases, cytoreduction, morbidity, HIPEC (hyperthermic intraperitoneal chemotherapy) RESULTS: Multivisceral resections should only be performed if an R0 status can be achieved for all tumor entities. Preoperative performance of an FDG-PET-CT scan (fluorodeoxyglucose positron emission tomography computed tomography scan) can help in the selection of appropriate patients. In gastric cancer, extensive lymphatic metastases are associated with a poor overall survival despite multivisceral resection. Recurrent rectal cancer shows elevated morbidity rates and also decreased overall survival rates. Maximum cytoreductive surgery can be conducted for peritoneal metastasized appendiceal neoplasms and colorectal cancer with acceptable morbidity and without an increased risk for reduced overall survival.

CONCLUSION

After adequate patient selection and exclusion of stage IV distant metastatic disease, multivisceral resections can be offered to patients with the goal of an R0 resection.

Anthracosilicosis mimicking extensive nodal metastasis from early gastric cancer: A case report

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Anthracosilicosis can mimic extensive node metastasis from gastric cancer.

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The PET-CT scan is not specific enough to detect metastatic lymph nodes precisely.

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Surgical exploration should be considered when the result of imaging studies is doubtful.

Introduction

Lymph node metastasis is one of the most important prognostic factors in gastric cancer and precise assessment of nodal status facilitates optimal therapeutic decisions. Many diagnostic modalities including endoscopic ultrasound (EUS), computed tomography (CT), and sometimes, positron emission tomography (PET) have been utilized to improve diagnostic accuracy in detecting metastatic lymph nodes; however, their accuracy remains unsatisfactory.

Presentation of case

We report a case of a 73-year old male patient who was erroneously diagnosed with stage IV gastric cancer due to the distant nodal metastasis from early gastric cancer lesion during the initial staging process. However, surgical exploration revealed an anthracosilicosis-associated lymphadenopathy that mimicked extensive distant nodal metastasis in the preoperative CT and PET-CT scans. The patient was finally diagnosed with stage I gastric cancer confined to the mucosa without nodal metastasis.

Discussion

We report a rare case of gastric cancer concurrent extensive nodal involvement of anthracosilicosis mimicking metastatic nodal disease in the imaging studies. This case implies that PET-CT scan for clinical staging is not specific enough to clearly delineate malignant lesions, causing a diagnostic dilemma.

Conclusion

When the characteristics of the primary tumor is poorly correlated to the findings of imaging studies, surgical exploration can be a viable option for a definitive diagnosis before making a hasty decision based only upon the diagnostic imaging results.