The value of restaging CT following neoadjuvant chemotherapy for resectable gastric cancer. A population-based study

Advanced Multiparametric MRI Strategies for Tumor Restaging After Neoadjuvant Therapy in Locally Advanced Gastric Cancer

BACKGROUND

This study tested the diagnostic accuracy of multiparametric magnetic resonance imaging (mpMRI) in restaging locally advanced gastric cancer after neoadjuvant therapy (NAT) using pathologic T stage (ypT) and pathologic N stage (ypN) as the reference standard.

METHODS

Between August 2022 and September 2023, the study enrolled a prospective cohort of 70 gastric cancer patients who underwent NAT and subsequent surgical resection. MRI procedures, including DLSB T2-weighted imaging (T2WI), ZOOMit diffusion-weighted imaging (DWI), and XD-VIBE dynamic contrast-enhanced imaging (DCE), were performed after NAT and before surgery. Four abdominal radiologists independently assigned radiologic T stage (yrT) and radiologic N stage (yrN) based on individual and combined sequences. Inter-reader agreement was quantified using Kendall's coefficient. Diagnostic accuracy was determined by comparing MRI assessments and pathologic outcomes, with pairwise comparisons analyzed via the McNemar test. Subgroup analysis evaluated the performance in identifying good responders to NAT.

RESULTS

Inter-reader agreement was almost perfect for T restaging and substantial for N restaging. Diagnostic accuracy for T restaging was 0.432 using DLSB-T2WI, 0.586 using ZOOMit DWI, 0.557 using XD-VIBE DCE, and 0.586 using mpMRI. The accuracy demonstrated by DWI, DCE and mpMRI was superior to that of T2WI (all P < 0.05). For N restaging, the accuracy of the mpMRI protocol was 0.443. Notably, mpMRI achieved an AUC of 0.879 (95% confidence interval 0.835-0.915) for differentiating ypT0-1 tumors.

CONCLUSIONS

Advanced mpMRI strategies can serve as a valuable tool for restaging gastric cancer after NAT. Accurately differentiating good responders to neoadjuvant therapy through mpMRI holds significant clinical implications for personalized treatment strategies and improved patient outcomes.

Diagnostic Potential of miR-143-5p, miR-143-3p, miR-551b-5p, and miR-574-3p in Chemoresistance of Locally Advanced Gastric Cancer: A Preliminary Study

Gastric cancer (GC) is one of the most frequently diagnosed cancers in the world. Although the incidence is decreasing in developed countries, the treatment results are still unsatisfactory. The standard treatment for locally advanced gastric cancer (LAGC) is gastrectomy with perioperative chemotherapy. The association of selected microRNAs (miRNAs) with chemoresistance was assessed using archival material of patients with LAGC. Histological material was obtained from each patient via a biopsy performed during gastroscopy and then after surgery, which was preceded by four cycles of neoadjuvant chemotherapy (NAC) according to the FLOT or FLO regimen. The expression of selected miRNAs in the tissue material was assessed, including miRNA-21-3p, miRNA-21-5p, miRNA-106a-5p, miRNA-122-3p, miRNA-122-5p, miRNA-143-3p, miRNA-143-5p, miRNA-203a-3p, miRNA-203-5p, miRNA-551b-3p, miRNA-551b-5p, and miRNA-574-3p. miRNA expression was assessed using quantitative reverse transcription polymerase chain reaction (qRT-PCR). The response to NAC was assessed using computed tomography of the abdomen and chest and histopathology after gastrectomy. The statistical analyses were performed using GraphPad Prism 9. The significance limit was set at p < 0.05. We showed that the expression of miR-143-3p, miR-143-5p, and miR-574-3p before surgery, and miR-143-5p and miR-574-3p after surgery, decreased in patients with GC. The expression of miR-143-3p, miR-143-5p, miR-203a-3p, and miR-551b-5p decreased in several patients who responded to NAC. The miRNA most commonly expressed in these cases was miRNA-551b-5p. Moreover, it showed expression in a patient whose response to chemotherapy was inconsistent between the histopathological results and computed tomography. The expression of miR-143-3p, miR-143-5p, miR-203a-3p, and miR-551b-5p in formalin-fixed paraffin-embedded tissue (FFPET) samples can help differentiate between the responders and non-responders to NAC in LAGC. miR-143-3p, miR-143-5p, and miR-574-3p expression may be used as a potential diagnostic tool in GC patients. The presence of miR-551b-5p may support the correct assessment of a response to NAC in GC via CT.

Advances in Diagnostic, Staging, and Restaging Evaluation of Esophageal and Gastric Cancer

The initial endoscopic and staging evaluation of esophagogastric cancers must be accurate and comprehensive in order to select the optimal therapeutic plan for the patient. Esophageal and gastric cancers (and treatment paradigms) are delineated by their proximity to the cardia (within 2 cm). The most frequent and important symptom that informs the initial staging evaluation is dysphagia, which is associated with at least cT3 or locally advanced disease. Endoscopic ultrasound is often needed if earlier stage disease is suspected, preferably in combination with endoscopic mucosal or submucosal resection or fine-needle aspiration of suspicious lymph nodes to enhance staging accuracy.

Deep Learning Radiomics Nomogram Based on Enhanced CT to Predict the Response of Metastatic Lymph Nodes to Neoadjuvant Chemotherapy in Locally Advanced Gastric Cancer

BACKGROUND

We aimed to construct and validate a deep learning (DL) radiomics nomogram using baseline and restage enhanced computed tomography (CT) images and clinical characteristics to predict the response of metastatic lymph nodes to neoadjuvant chemotherapy (NACT) in locally advanced gastric cancer (LAGC).

METHODS

We prospectively enrolled 112 patients with LAGC who received NACT from January 2021 to August 2022. After applying the inclusion and exclusion criteria, 98 patients were randomized 7:3 to the training cohort (n = 68) and validation cohort (n = 30). We established and compared three radiomics signatures based on three phases of CT images before and after NACT, namely radiomics-baseline, radiomics-delta, and radiomics-restage. Then, we developed a clinical model, DL model, and a nomogram to predict the response of LAGC after NACT. We evaluated the predictive accuracy and clinical validity of each model using the receiver operating characteristic curve and decision curve analysis, respectively.

RESULTS

The radiomics-delta signature was the best predictor among the three radiomics signatures. So, we developed and validated a DL delta radiomics nomogram (DLDRN). In the validation cohort, the DLDRN produced an area under the receiver operating curve of 0.94 (95% confidence interval, 0.82-0.96) and demonstrated adequate differentiation of good response to NACT. Furthermore, the DLDRN significantly outperformed the clinical model and DL model (p < 0.001). The clinical utility of the DLDRN was confirmed through decision curve analysis.

CONCLUSIONS

In patients with LAGC, the DLDRN effectively predicted a therapeutic response in metastatic lymph nodes, which could provide valuable information for individualized treatment.

Imaging advances in efficacy assessment of gastric cancer neoadjuvant chemotherapy

Effective neoadjuvant chemotherapy (NAC) can improve the survival of patients with locally progressive gastric cancer, but chemotherapeutics do not always exhibit good efficacy in all patients. Therefore, accurate preoperative evaluation of the effect of neoadjuvant therapy and the appropriate selection of surgery time to minimize toxicity and complications while prolonging patient survival are key issues that need to be addressed. This paper reviews the role of three imaging methods, morphological, functional, radiomics, and artificial intelligence (AI)-based imaging, in evaluating NAC pathological reactions for gastric cancer. In addition, the advantages and disadvantages of each method and the future application prospects are discussed.

Serum Interleukin 6 Level is Associated With Overall Survival and Treatment Response in Gastric and Gastroesophageal Junction Cancer

OBJECTIVE

To identify novel prognostic and predictive biomarkers for gastric and gastroesophageal junction (G+GEJ) adenocarcinoma.

BACKGROUND

There are few biomarkers to guide treatment for G+GEJ. The systemic inflammatory response of G+GEJ patients is associated with survival. In this study, we evaluated the relationship of circulating serum cytokine levels with overall survival (OS) and pathologic tumor regression grade (TRG) in G+GEJ patients.

PATIENTS AND METHODS

We queried the UT Southwestern gastric cancer biobank to identify consecutive patients diagnosed with G+GEJ from 2016 to 2022; these patients had pretreatment serum collected at diagnosis. For patients who received neoadjuvant therapy, an additional serum sample was collected immediately before surgical resection. An unbiased screen of 17 cytokines was measured in a discovery cohort. A multivariable Cox proportional hazards model was used to assess the association of cytokine concentration with OS. Findings were validated in additional patients. In patients who received neoadjuvant therapy, we assessed whether the change in interleukin 6 (IL-6) after therapy was associated with TRG.

RESULTS

Sixty-seven patients were included in the discovery cohort, and IL-6 was the only pretreatment cytokine associated with OS; this was validated in 134 other patients (hazard ratio: 1.012 per 1 pg/mL increase, 95% CI: 1.006-1.019, P = 0.0002). Patients in the top tercile of IL-6 level had worse median OS (10.6 months) compared with patients in the intermediate (17.4 months) and bottom tercile (35.8 months, P < 0.0001). Among patients who underwent neoadjuvant therapy (n = 50), an unchanged or decrease in IL-6 level from pretreatment to posttreatment, had a sensitivity and specificity of 80% for predicting complete or near-complete pathologic tumor regression (TRG 0-1).

CONCLUSIONS

Pretreatment serum level of IL-6 is a promising prognostic biomarker for G+GEJ patients. Comparing pre and post-neoadjuvant IL-6 levels may predict pathologic response to neoadjuvant therapy.

Does the ypTNM-stage adequately predict long-term survival rates in gastric cancer patients receiving neoadjuvant chemotherapy followed by radical resection?

BACKGROUND

Following neoadjuvant chemotherapy (NAC) for resectable gastric cancer, the prognostic adequacy of the UICC staging system needs to be investigated. In particular to explore whether the ypTNM curves for radically resected gastric cancer patients receiving NAC follow the stage-matched survival curves of radically resected chemo-naïve patients (pTNM). Further, to disclose any interaction between the TNM-response mode to NAC and stage-specific survival rates, i.e., whether survival for a particular pathological disease stage was dependent on whether this was reached through a downstaging or as stable disease following NAC.

MATERIAL AND METHODS

Retrospective study on radically resected patients ≤ 75 years of age with gastric adenocarcinoma stages I-III diagnosed during 2001-2016. The patients constitute two population-based cohorts; the SURG-group with n = 121 patients treated before 2007 when NAC was introduced, and the NAC-group with n = 126 patients diagnosed since early 2007, receiving NAC and subsequent radical resection.

RESULTS

Long-term survival rates were similar when specific ypTNM-stages were compared to their corresponding pTNM chemo-naïve counterparts. The dichotomised N0 vs. N + had a substantial impact on the long-term survival rates in both groups, however, no discrepancy in long-term survival rates between pN0 vs. ypN0, and pN + vs. ypN + was found. The pathological stage determined long-term survival rates irrespective of the baseline disease stage, as no interaction between the response mode and stage-specific survival rates was found.

CONCLUSIONS

Survival curves for specific ypTNM-stages following NAC did not differ from the corresponding survival curves of their chemo-naïve pTNM counterparts. The interpretation is that NAC affected the gastric cancer, lymph nodes, and micrometastases, in such a way that the final ypTNM-stage provided similar prognostic information as the chemo-naïve pTNM-stages. Survival rates were contingent on the final ypTNM-stages alone, and not influenced by the response mode to reach that particular disease stage, or predetermined by the original clinical TNM-stage.

Gastric hydrodistension CT versus CT without gastric distension in preoperative TN staging of gastric carcinoma: analysis of single-center cancer registry

Accurate staging of gastric cancer is essential for the selection and optimization of therapy. Hydrodistension of the stomach is recommended to improve the accuracy of preoperative staging with contrast-enhanced multidetector computed tomography (MDCT). This study compares the performance of contrast-enhanced gastric water distension versus a nondistension MDCT protocol for T and N staging and serosal invasion in comparison to surgical histopathology. After propensity score matching, 86 patients in each group were included for analysis. The overall accuracy of distension versus nondistension group in T staging was 45% (95% CI 35-56) and 55% (95% CI 44-65), respectively (p = 0.29). There was no difference in the sensitivity and specificity in individual T staging and assessment of serosal invasion (all p > 0.41). Individual stage concordance with pathology was not significantly different (all p > 0.41). The overall accuracy of N staging was the same for distension and nondistension groups (51% [95% CI 40-62]). The majority of N0 staging (78-81%) were correctly staged, whereas N3 staging cases (63-68%) were predominantly understaged. In summary, there was no significant difference in the diagnostic performance of individual TN staging and assessment of serosal invasion using MDCT with or without gastric water distension.

Gastric Cancers Missed at Upper Endoscopy in Central Norway 2007 to 2016-A Population-Based Study

Simple Summary

Stomach cancer may be missed during upper endoscopy. We have examined how often this occurs and identified factors associated with missed cancers. Among 730 patients with gastric cancer, 67 (9.2%) were missed during endoscopy 6 to 36 months prior to the cancer diagnosis. Missed cancers were more often located in the upper part of the stomach, of Lauren’s diffuse histologic type and more frequent in patients with previous Billroth II operation. The missed cancers were diagnosed at somewhat earlier stages than the non-missed cancers. In missed cancers, an ulceration was more often found in patients with shorter time interval between the first endoscopy and the endoscopy where the cancer was diagnosed. The factors associated with missed stomach cancers should be kept in mind by doctors performing endoscopies as this may lead to an earlier diagnosis of cancer.

Abstract

Background: The rates of missed gastric cancers (MGC) at upper endoscopy (UE) has been reported at 5–10% in Western countries. We aimed to calculate the rate of MGC and identify factors associated with MGC. Methods: Retrospective population-based cohort study including 730 patients diagnosed with gastric adenocarcinoma in Central Norway 2007–2016. MGCs were incident gastric adenocarcinomas diagnosed 6–36 months after a previous UE. Factors associated with MGC were examined. Definitely missed (UE 6–12 months prior) and potentially missed (UE 12–36 months prior) MGCs were compared. Results: Sixty-seven (9.2%) of 730 gastric cancers were MGC. MGC were associated with localization (p = 0.009) and more frequent in the corpus, Lauren’s histological type (p = 0.028) and diffuse type more prevalent, and previous Billroth 2-operation (14.9% vs. 4.7%, p = 0.001). MGCs were diagnosed at earlier stages (p = 0.037). An ulceration was more common in patients with definitely missed than potentially MGC (40.9% vs. 17.8%, p = 0.041). Conclusions: MGC accounted for 9.2% of gastric cancers in Central Norway. MGC were associated with localization in the corpus, Lauren´s diffuse type and previous Billroth-2-operation. Intensified follow-up and adequate biopsy sampling of patients with gastric ulcerations could reduce the rate of missed gastric cancers.

[Complete response after neoadjuvant therapy for gastric cancer: implications for surgery]

BACKGROUND

Perioperative or neoadjuvant therapy is the mainstay of treatment for locally advanced gastric cancer in Europe; however, data regarding possible modifications in the surgical strategy depending on the response to preoperative treatment are lacking.

METHODS

This review was carried out based on a search of the relevant contemporary literature regarding neoadjuvant or perioperative treatment for gastric adenocarcinoma and the implications of tumor response for the subsequent surgical treatment.

RESULTS

The most recent randomized trials showed a survival benefit after perioperative or neoadjuvant treatment for gastric cancer. Due to the variable response to the preoperatively administered part of the therapy, including complete response, it appears reasonable to develop an individualized surgical approach; however, scientific results supporting this approach are limited due to the variable quality of the surgical resection provided in these studies and the limited rate of complete response to preoperative treatment. Moreover, the reliability of clinical restaging after preoperative treatment is also limited. On the other hand, there is currently evidence that supports a re-evaluation of the necessary resection margins for partial gastrectomy in advanced gastric cancer with the help of intraoperative frozen sections and new reconstruction methods.

CONCLUSION

The current evidence does not support the implementation of a complete organ-sparing strategy with active follow-up surveillance for gastric cancer.; however, stomach-preserving partial gastrectomy techniques could be applied for advanced disease more often in the future.