Usefulness of Two-Dimensional Values Measured Using Preoperative Multidetector Computed Tomography in Predicting Lymph Node Metastasis of Gastric Cancer

Genomic events stratifying prognosis of early gastric cancer

BACKGROUND

The purpose of the study was to conduct a comprehensive genomic characterization of gene alterations, microsatellite instability (MSI), and tumor mutational burden (TMB) in submucosal-penetrating (Pen) early gastric cancers (EGCs) with varying prognoses.

METHODS

Samples from EGC patients undergoing surgery and with 10-year follow-up data available were collected. Tissue genomic alterations were characterized using Trusight Oncology panel (TSO500). Pathway instability (PI) scores for a selection of 218 GC-related pathways were calculated both for the present case series and EGCs from the TCGA cohort.

RESULTS

Higher age and tumor location in the upper-middle tract are significantly associated with an increased hazard of relapse or death from any cause (p = 0.006 and p = 0.032). Even if not reaching a statistical significance, Pen A tumors more frequently present higher TMB values, higher frequency of MSI-subtypes and an overall increase in PI scores, along with an enrichment in immune pathways. ARID1A gene was observed to be significantly more frequently mutated in Pen A tumors (p = 0.006), as well as in patients with high TMB (p = 0.027). Tumors harboring LRP1B alterations seem to have a higher hazard of relapse or death from any cause (p = 0.089), being mutated mainly in relapsed patients (p = 0.093).

CONCLUSIONS

We found that the most aggressive subtype Pen A is characterized by a higher frequency of ARID1A mutations and a higher genetic instability, while LRP1B alterations seem to be related to a lower disease-free survival. Further investigations are needed to provide a rationale for the use of these markers to stratify prognosis in EGC patients.

Prediction of lymph node metastasis in advanced gastric adenocarcinoma based on dual-energy CT radiomics: focus on the features of lymph nodes with a short axis diameter ≥6 mm

Objective

To explore the value of the features of lymph nodes (LNs) with a short-axis diameter ≥6 mm in predicting lymph node metastasis (LNM) in advanced gastric adenocarcinoma (GAC) based on dual-energy CT (DECT) radiomics.

Materials and methods

Data of patients with GAC who underwent radical gastrectomy and LN dissection were retrospectively analyzed. To ensure the correspondence between imaging and pathology, metastatic LNs were only selected from patients with pN3, nonmetastatic LNs were selected from patients with pN0, and the short-axis diameters of the enrolled LNs were all ≥6 mm. The traditional features of LNs were recorded, including short-axis diameter, long-axis diameter, long-to-short-axis ratio, position, shape, density, edge, and the degree of enhancement; univariate and multivariate logistic regression analyses were used to establish a clinical model. Radiomics features at the maximum level of LNs were extracted in venous phase equivalent 120 kV linear fusion images and iodine maps. Intraclass correlation coefficients and the Boruta algorithm were used to screen significant features, and random forest was used to build a radiomics model. To construct a combined model, we included the traditional features with statistical significance in univariate analysis and radiomics scores (Rad-score) in multivariate logistic regression analysis. Receiver operating curve (ROC) curves and the DeLong test were used to evaluate and compare the diagnostic performance of the models. Decision curve analysis (DCA) was used to evaluate the clinical benefits of the models.

Results

This study included 114 metastatic LNs from 36 pN3 cases and 65 nonmetastatic LNs from 28 pN0 cases. The samples were divided into a training set (n=125) and a validation set (n=54) at a ratio of 7:3. Long-axis diameter and LN shape were independent predictors of LNM and were used to establish the clinical model; 27 screened radiomics features were used to build the radiomics model. LN shape and Rad-score were independent predictors of LNM and were used to construct the combined model. Both the radiomics model (area under the curve [AUC] of 0.986 and 0.984) and the combined model (AUC of 0.970 and 0.977) outperformed the clinical model (AUC of 0.772 and 0.820) in predicting LNM in both the training and validation sets. DCA showed superior clinical benefits from radiomics and combined models.

Conclusion

The models based on DECT LN radiomics features or combined traditional features have high diagnostic performance in determining the nature of each LN with a short-axis diameter of ≥6 mm in advanced GAC.

A European Society of Oncologic Imaging (ESOI) survey on the radiological assessment of response to oncologic treatments in clinical practice

OBJECTIVES

To present the results of a survey on the assessment of treatment response with imaging in oncologic patient, in routine clinical practice. The survey was promoted by the European Society of Oncologic Imaging to gather information for the development of reporting models and recommendations.

METHODS

The survey was launched on the European Society of Oncologic Imaging website and was available for 3 weeks. It consisted of 5 sections, including 24 questions related to the following topics: demographic and professional information, methods for lesion measurement, how to deal with diminutive lesions, how to report baseline and follow-up examinations, which previous studies should be used for comparison, and role of RECIST 1.1 criteria in the daily clinical practice.

RESULTS

A total of 286 responses were received. Most responders followed the RECIST 1.1 recommendations for the measurement of target lesions and lymph nodes and for the assessment of tumor response. To assess response, 48.6% used previous and/or best response study in addition to baseline, 25.2% included the evaluation of all main time points, and 35% used as the reference only the previous study. A considerable number of responders used RECIST 1.1 criteria in daily clinical practice (41.6%) or thought that they should be always applied (60.8%).

CONCLUSION

Since standardized criteria are mainly a prerogative of clinical trials, in daily routine, reporting strategies are left to radiologists and oncologists, which may issue local and diversified recommendations. The survey emphasizes the need for more generally applicable rules for response assessment in clinical practice.

CRITICAL RELEVANCE STATEMENT

Compared to clinical trials which use specific criteria to evaluate response to oncological treatments, the free narrative report usually adopted in daily clinical practice may lack clarity and useful information, and therefore, more structured approaches are needed.

KEY POINTS

· Most radiologists consider standardized reporting strategies essential for an objective assessment of tumor response in clinical practice. · Radiologists increasingly rely on RECIST 1.1 in their daily clinical practice. · Treatment response evaluation should require a complete analysis of all imaging time points and not only of the last.

Establishment of Decision Rules and Risk Assessment Model for Preoperative Prediction of Lymph Node Metastasis in Gastric Cancer

Background: Preoperative accurate prediction of lymph node status is especially important for the formulation of treatment plans for patients with gastric cancer (GC). The purpose of this study was to establish decision rules and a risk assessment model for lymph node metastasis (LNM) in GC using preoperative indicators. Methods: The clinical data of 554 patients who underwent gastrectomy with D2 lymphadenectomy were collected. A 1:1 propensity score matching (PSM) system was used, and the clinical data of the matched 466 patients were further analyzed. The important risk factors for LNM were extracted by the random forest algorithm, and decision rules and nomogram models for LNM were constructed with a classification tree and the "rms" package of R software, respectively. Results: Tumor size (OR: 2.058; P = 0.000), computed tomography (CT) findings (OR: 1.969; P = 0.001), grade (OR: 0.479; P = 0.000), hemoglobin (Hb) (OR: 1.211; P = 0.005), CEA (OR: 1.111; P = 0.017), and CA19-9 (OR: 1.040; P = 0.033) were independent risk factors for LNM in GC. Tumor size did rank first in the ranking of important factors for LNM in GC and was the first-level segmentation of the two initial branches of the classification tree. The accuracy, sensitivity, specificity, and positive predictive value of the decision rules in diagnosing preoperative LNM in GC were 75.6, 85.7, 73.9, 73.5, and 79.3%, respectively. The accuracy, sensitivity, and specificity of the risk assessment model in predicting preoperative LNM in GC were 79.3, 80.3, and 79.4%, respectively. Conclusion: Tumor size was the most important factor for evaluating LNM in GC. This decision rules and nomogram model constructed to take into account tumor size, CT findings, grade, hemoglobin, CEA, and CA19-9 effectively predicted the incidence of LNM in preoperative GC.

Metastatic patterns and surgical methods for lymph nodes No. 5 and No. 6 in proximal gastric cancer

Objective

The current surgical treatment guidelines for early proximal gastric cancer (PGC) still lack agreement. Lymphadenectomy of lymph nodes No. 5 and No. 6 is the major difference between total and proximal gastrectomy. We elucidated the appropriate surgical procedure for PGC by investigating the pathological characteristics and prognostic significance of lymph nodes No. 5 and No. 6.

Methods

In total, 333 PGC patients who underwent total gastrectomy were enrolled in this study. We investigated their clinicopathological characteristics and the metastatic patterns of the lymph nodes. Patients with metastasis in lymph nodes No. 5 and No. 6 were combined into one group and we compared the difference in survival between those with and without metastasis in lymph nodes No. 5, 6 (lymph nodes No. 5 and No. 6 in any group of metastasis) for different subgroups.

Results

The metastatic rates for lymph nodes No. 5 and No. 6 in PGC were 9.91% and 16.11%, respectively. The metastatic rate for both lymph nodes No. 5, 6 was 20.42%. Multivariate analysis showed that positive metastasis in lymph node No. 4, depth of invasion, and tumor size were independently correlated with the presence of metastasis in lymph nodes No. 5, 6.

Conclusions

When lymph node No. 4 is positive (intraoperative pathology) or tumor size ≥5 cm or T4 stage, lymphadenectomy should be performed for lymph nodes No. 5 and No. 6, and total gastrectomy is recommended.

Value of double contrast-enhanced ultrasonography in determining pathological features of advanced gastric cancer

AIM

To investigate the characteristics and clinical value of double contrast-enhanced ultrasonography (DCUS) in advanced gastric cancer (GC) with different pathological characteristics.

METHODS

Seventy-three patients with pathologically confirmed advanced GC were included. According to the pathological type, they were divided into a mucinous carcinoma group (31 cases) and a non-mucinous carcinoma group (42 cases, including 23 cases of poorly differentiated and undifferentiated carcinoma and 19 cases of moderately differentiated and well-differentiated carcinoma). All patients received DCUS before surgery, and the DCUS results were compared with pathological results after surgery.

RESULTS

Mucinous carcinoma mainly showed layered enhancement, and non-mucinous carcinoma mainly showed non-layered enhancement. The difference in the enhanced features between the two groups was statistically significant (P < 0.05). The sensitivity, specificity, and accuracy of layered enhancement in diagnosing mucinous carcinoma were 77.42%, 85.71%, and 82.19%, respectively. The peak intensity and enhancement intensity in the mucinous carcinoma group were significantly lower than those in the non-mucinous carcinoma group (P < 0.05). In the non-mucinous carcinoma group, the peak intensity and enhancement intensity of poorly differentiated and undifferentiated carcinoma were significantly higher than those of moderately differentiated and well-differentiated carcinoma (P < 0.05).

CONCLUSION

The enhanced characteristics and parameter characteristics of advanced GC analyzed by DCUS can preliminarily determine the pathological type and differentiation degree.

Is Lymph Node Size a Reliable Factor for Estimating Lymph Node Metastasis in Early Gastric Cancer?

Purpose

Pre-operative lymph node (LN) size is a valuable parameter for determining treatment strategy for gastric cancer. However, a correlation between LN size and metastasis has not been established.

Materials and Methods

Thirty-six LN-positive (LNP) and matched 36 LN-negative (LNN) patients were included, and pathology slides of the LNs of these patients were reviewed. All the LNs were measured along the long-axis (LA) and short-axis (SA), manually.

Results

Average retrieved LNs were 37.3±19.8 and 40.5±11.6 in the LNN and LNP groups, respectively. In total 2,800 LNs, including 136 metastatic LNs (MLNs) and 2,664 non-metastatic LNs (nMLNs), were evaluated. Mean length was significantly more in MLNs along both, the LA and SA (MLN_LA vs. nMLN_LA: 4.97±3.84 vs. 3.37±2.40 mm, MLN_SA vs. nMLN_SA: 3.86±3.19 vs. 2.43±1.59 mm; P<0.001). However, 92.6% (126/136) and 95.6% (130/136) of MLNs were <10 mm along the LA and SA, respectively. In addition, only 22.2% of the LNP group exhibited an MLN as the largest LN.

Conclusions

Pre-operative multi-detector computed tomography has limited ability in estimating the presence of metastasis in LNs because most MLNs are less than 10 mm, and only a small proportion of the LNP group exhibits an MLN as the largest MLN.

Preoperative lymph node size is helpful to predict the prognosis of patients with stage III gastric cancer after radical resection

OBJECTIVE

To investigate the association between preoperative lymph node size (Ns) and prognosis of radical gastrectomy for gastric cancer.

METHODS

The clinical and pathological data of 970 patients undergoing radical gastrectomy for gastric cancer were retrospectively analyzed. The correlation between Ns and the identified variables for the prediction of overall survival (OS) and disease-free survival (DFS) was examined.

RESULTS

Three hundred and thirty-one (34.1%) of 970 patients developed recurrence, which was most commonly in local lymph nodes. The average Ns was 1.52 cm in patients with recurrence, which was significantly higher than the 1.14 cm observed in patients without recurrence (p < 0.001). Patients were categorized into three groups as follows (Ns category):Ns0:≤1.10 cm, Ns1:1.10-1.70 cm, and Ns2:>1.70 cm, determined using the X-tile program. In univariate and multivariate analyses, Ns category, age, tumor size, lymphadenectomy, adjuvant chemotherapy and TNM stage were independent prognostic factors for DFS. Stratified analysis only in stage III was there a significant difference in the Ns category based on TNM stage. Furthermore, in the stage III subgroup, univariate and multivariate analyses revealed that Ns category, lymphadenectomy, and TNM stage was independent prognostic factors for DFS. A nomogram were developed to predict the 3-year DFS rate.

CONCLUSIONS

Preoperative Ns is an independent prognostic factor for DFS of patients after radical surgery for gastric cancer. The proposed nomogram combined with Ns could be a simple and effective approach to predict the 3-year DFS of stage III patients.

Value and impact factors of multidetector computed tomography in diagnosis of preoperative lymph node metastasis in gastric cancer: A PRISMA-compliant systematic review and meta-analysis

BACKGROUND

Multidetector computed tomography (MDCT) exhibited wide ranges of sensitivities and specificities for lymph node assessment of gastric cancer (GC) in several individual studies. This present meta-analysis was carried out to evaluate the value of MDCT in diagnosis of preoperative lymph node metastasis (LNM) and to explore the impact factors that might explain the heterogeneity of its diagnostic accuracy in GC.

METHODS

A comprehensive search was conducted to collect all the relevant studies about the value of MDCT in assessing LNM of GC within the PubMed, Cochrane library and Embase databases up to Feb 2, 2016. Two investigators independently screened the studies, extracted data, and evaluated the quality of included studies. The sensitivity, specificity, and area under ROC curve (AUC) were pooled to estimate the overall accuracy of MDCT. Meta-regression and subgroup analysis were carried out to identify the possible factors influencing the heterogeneity of the accuracy.

RESULTS

A total of 27 studies with 6519 subjects were finally included. Overall, the pooled sensitivity, specificity, and AUC were 0.67 (95% CI: 0.56-0.77), 0.86 (95% CI: 0.81-0.90), and 0.86 (95% CI: 0.83-0.89), respectively. Meta-regression revealed that MDCT section thickness, proportion of serosal invasion, and publication year were the main significant impact factors in sensitivity, and MDCT section thickness, multiplanar reformation (MPR), and reference standard were the main significant impact factors in specificity. After the included studies were divided into 2 groups (Group A: studies with proportion of serosa-invasive GC subjects ≥50%; Group B: studies with proportion of serosa-invasive GC subjects <50%), the pooled sensitivity in Group A was significantly higher than in Group B (0.84 [95% CI: 0.75-0.90] vs 0.55 [95% CI: 0.41-0.68], P < .01). For early gastric cancer (EGC), the pooled sensitivity, specificity, and AUC were 0.34 (95% CI: 0.15-0.61), 0.91 (95% CI: 0.84-0.95), and 0.83 (95% CI: 0.80-0.86), respectively.

CONCLUSION

To summarize, MDCT tends to be adequate to assess preoperative LNM in serosa-invasive GC, but insufficient for non-serosa-invasive GC (particularly for EGC) owing to its low sensitivity. Proportion of serosa-invasive GC subjects, MDCT section thickness, MPR, and reference standard are the main factors influencing its diagnostic accuracy.