Comparison of tumor regression grading systems for locally advanced gastric adenocarcinoma after neoadjuvant chemotherapy

Helicobacter pylori reversing the landscape of neoadjuvant immunotherapy for microsatellite stable gastric cancer: a multicenter cohort study

BACKGROUND

Microsatellite stable (MSS) gastric cancer (GC) is largely unresponsive to immunotherapy, presenting a persistent and formidable challenge in the field. Patients with advanced GC and Helicobacter pylori (H. pylori) infection have shown benefits from immunotherapy. However, it remains unreported whether neoadjuvant immunotherapy is beneficial for H. pylori-positive MSS GC patients.

METHODS

This retrospective cohort study analyzed data from GC patients treated at three medical centers in China between January 1, 2014, and July 1, 2024. Patients with gastric adenocarcinoma or adenocarcinoma of the gastroesophageal junction underwent testing for H. pylori infection prior to receiving neoadjuvant therapy.

RESULTS

In this retrospective analysis, those positive for H. pylori had a higher objective response rate of 63.77% (95% CI, 51.98-74.11%) compared to 47.73% (95% CI, 39.39-56.19%) in H. pylori-negative patients. Pathological complete remission was higher in H. pylori-positive patients at 17.39% (95% CI, 10.24-27.98%) versus 15.91% (95% CI, 10.65-23.10%). Logistic regression analysis revealed a strong correlation between H. pylori positivity and increased objective remission rate (P = 0.031, OR = 1.928, 95% CI 1.06-3.51). In H. pylori-positive MSS GC patients receiving neoadjuvant immunotherapy pCR rates can reach 27.27% (95% CI, 15.07-44.21%), much higher than the 8.33% (95% CI, 2.87-21.82%) in neoadjuvant chemotherapy patients. Survival analysis showed a 3-year OS rate of 74.2% (95% CI, 56.75-86.30%) in the H. pylori-positive group and 64.3% (95% CI, 51.20-75.55%) in the H. pylori-negative group, and the hazard ratio (HR) of these two groups was 0.50 (95% CI, 0.28-0.87; P <.001). Multivariable analysis for OS further showed the survival benefit of H. pylori, with HRs of 0.51 (95% CI, 0.29-0.91; P = 0.02).

CONCLUSIONS

H. pylori infection has emerged as a favorable factor for neoadjuvant immunotherapy in MSS GC, underscoring the importance of considering H. pylori status in preoperative treatment strategies.

Prime suspect or collective responsibility: Impact of specific lymph node station dissection on short- and long-term outcomes among locally advanced gastric cancer patients after neoadjuvant chemotherapy

BACKGROUND

Lymphatic route is the main pathway for gastric cancer (GC) spread, and lymph node (LN) involvement is a major prognostic factor after curative resection. The aim of this study was to assess the outcomes of specific LN station dissection.

METHODS

Patients with locally advanced (cT2-4N0-3M0) GC who underwent multimodal treatment between 2013 and 2023 were included in the study. Patients who had not undergone gastrectomy, had early (cT1) or metastatic GC, who had undergone multiorgan resections, palliative care, had died before the end of curative-intent planned treatment, or had incomplete clinical or pathological information were excluded. The primary endpoint was the development of serious complications, and the secondary outcome was OS.

RESULTS

Mulivariable analysis revealed, that among patients who received neoadjuvant chemotherapy (NAC), it was observed that station 10 lymphadenectomy was associated with a higher risk of serious postoperative complications. (27.6 % vs 8.7 %; OR = 3.28) Among the no-NAC group, it was observed that station 13 lymphadenectomy was associated with a higher risk of serious postoperative complications. (57.1 % vs 13.2 %; OR = 6.96). Among the NAC group, a lower risk of death was observed in patients with station 8 (HR = 0.53) or 11 lymphadenectomy (HR = 0.53).

CONCLUSION

While D2 lymphadenectomy remains crucial, particularly in in high-volume, experienced GC centers, the necessity of a more extensive D2+ lymphadenectomy is not supported by our findings. Moreover, we aimed to highlight the importance of tailored surgical approaches and emphasize the significance of LN station dissection in influencing both short-term complications and long-term survival outcomes.

Impact of pathological complete response on survival in gastric cancer after neoadjuvant chemotherapy: a propensity score matching analysis

PURPOSE

The survival benefits of neoadjuvant chemotherapy (NAC) for locally advanced gastric cancer (LAGC) patients are inconsistent. This study aims to investigate how different tumor regression grades (TRG) influence the survival gains associated with NAC treatment.

METHODS

This study compared the treatment outcomes of patients who underwent CSC (neoadjuvant chemotherapy - surgery - adjuvant chemotherapy) with those receiving traditional SC (surgery - adjuvant chemotherapy) treatment. Propensity score matching (PSM) was employed to minimize potential biases arising from differences in baseline characteristics and intervention factors between the treatment groups. After PSM, the CSC cohort was stratified according to TRGs, and their survival outcomes were compared to assess the impact of TRGs on survival gains associated with NAC.

RESULTS

Before PSM, a total of 506 patients were enrolled: 291 in the CSC cohort and 215 in the SC cohort. The CSC cohort had a lower 3-year survival rate (3Y-SR) than the SC cohort (64.6% vs. 76%). In the CSC cohort, patients who achieved pathological complete response (pCR, 12.1%, 26/215) demonstrated significantly improved 3Y-SR (95.5%). After PSM, 110 patients were matched in each cohort. The 3Y-SR was similar between the CSC cohort (68.3%) and the SC cohort (63.6%). In the CSC cohort, 12.7% (14/110) of patients achieved pCR. Subgroup analysis revealed that the pCR subgroup (3Y-SR 100%) was the only subgroup within the CSC cohort that maintained significantly improved survival compared to the SC cohort. Better tumor differentiation was the only pre-treatment factor significantly associated with achieving pCR (p < 0.001).

CONCLUSION

In this retrospective study, LAGC patients who achieved pCR after NAC demonstrated significantly better survival outcomes compared to other response groups. The study found tumor differentiation was a potential predictor of pCR.

IDO1 Expression and CD8+ T-Cell Levels Are Useful Prognostic Biomarkers in Preoperative Gastric Cancer Specimens Before Neoadjuvant Chemotherapy

The tumor immune microenvironment occupies an important position in gastric cancer. In this study, we investigated the relationship between indoleamine 2,3-dioxygenase 1 (IDO1), programmed cell death 1 ligand (PD-L1) expressioon, and CD8+ T-cell levels and their efficacy and prognostic value in preoperative gastric cancer specimens before neoadjuvant chemotherapy (NAC). A total of 162 patients with locally advanced gastric cancer were collected in this study. IDO1, PD-L1 expression, and CD8+ T-cell levels in the biopsy samples was detected by immunohistochemical staining, and the relationship between these indexes and the patients' clinicopathological parameters, chemotherapeutic efficacy, and prognosis were investigated. The IDO1 positivity rate was 43.2%. High expression of IDO1 was significantly associated with poor chemotherapeutic efficacy, lymph node metastasis (P<0.05). The PD-L1 positivity rate (using the combined positive score) was 38.2%, and was not related to any clinicopathological variable. Higher CD8+ T-cell levels were associated with a lower rate of lymph node metastasis and lower ypTNM stage (P<0.05). Higher CD8+ T-cell levels were negatively correlated with IDO1 expression (r=-0.224, P<0.05) and positively correlated with PD-L1 expression (r=0.254, P<0.05). Cox regression analysis demonstrated that higher CD8+ T-cell levels was an independent risk factor for overall survival (OS) and the expression of IDO1 had a significantly poorer disease-free survival (DFS). Overexpression of IDO1 and lower CD8+ T-cell levels were associated with poor survival in patients with gastric cancer who received neoadjuvant chemotherapy, and overexpression of IDO1 were associated with the poor tumor response. Our data suggest that IDO1 and CD8 testing of biopsy specimens might be a simple and effective prognostic biomarker for gastric cancer, and IDO1 could predict efficacy of neoadjuvant chemotherapy in gastric cancer.

Immunosuppressive MFAP2+ cancer associated fibroblasts conferred unfavorable prognosis and therapeutic resistance in gastric cancer

PURPOSE

To explore the predictive merit of MFAP2+ cancer associated fibroblasts (CAFs) infiltration for clinical outcomes and adjuvant chemotherapy or immunotherapy responsiveness in gastric cancer (GC).

METHODS

In this study, several independent cohorts were included respectively to dissect the relationship of clinical outcomes, therapeutic responses and tumor microenvironment with different MFAP2+ CAFs infiltration. Drug sensitivity analysis was conducted to predict the relationship between MFAP2+ CAFs infiltration and targeted drug response. Kaplan-Meier curves and the log-rank test were used to compare clinical outcomes of patients with different MFAP2+ CAFs infiltration.

RESULTS

High MFAP2+ CAFs infiltration yielded inferior prognosis in terms of overall survival, progress free survival and recurrence free survival in GC. Patients with low MFAP2+ CAFs infiltration were more likely to gain benefit from adjuvant therapy. Moreover, low MFAP2+ CAFs infiltration could predict a promising response to immunotherapy in GC patients. MFAP2+ CAFs with immunosuppressive features were highly relevant to immune evasive contexture characterized by the dysfunction of CD8+ T cells. We found that MFAP2+ CAFs communicated with T cells, B cells and Macrophages through releasing macrophage migration inhibitor factor (MIF), which further suggested that MFAP2+ CAFs might promote therapeutic resistance through regulating T cells dysfunction and M2 macrophages polarization.

CONCLUSION

Immunosuppressive MFAP2+ CAFs constructed an immune evasive tumor microenvironment characterized by incapacitated immune effector cells, consequently predicting inferior clinical outcomes and response on adjuvant therapy and immunotherapy in patients with GC. The potential of immunosuppressive MFAP2+ CAFs as a therapeutic target for GC deserved thoroughly exploration.

Hyperthermic Intraperitoneal Chemotherapy (HIPEC), Oncological Outcomes and Long-Term Survival among Patients with Gastric Cancer and Limited Peritoneal Disease Progression after Neoadjuvant Chemotherapy

INTRODUCTION

The role of surgery in stage IV gastric cancer with peritoneal metastasis (PM) remains unclear. The objective of the current single-center study was to define the impact of gastrectomy with cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) on outcomes among Central European GC patients with limited peritoneal disease progression after neoadjuvant chemotherapy (NAC).

METHODS

Patients with histologically confirmed GC who underwent curative-intent multimodal treatment between 2013 and 2023 were included. Patients without adenocarcinoma, who did not undergo gastrectomy, had early (cT1) or metastatic GC at the time of initial diagnosis, who underwent multivisceral resection, incomplete cytoreduction or palliative care, died before planned curative-intent treatment, or had incomplete clinical or pathological missing information were excluded.

RESULTS

A total of 74 patients who underwent curative-intent treatment for GC with PM were included in the final analytic cohort. Patients who underwent gastrectomy with CRS+HIPEC were less likely to achieve TOO (CRS+HIPEC: 28% vs. CRS: 57.1%, p = 0.033) compared with individuals after CRS alone. Specifically, patients who underwent gastrectomy with CRS+HIPEC had a higher likelihood of postoperative complications (CRS+HIPEC: 48% vs. CRS: 20.4%, p = 0.018) and longer hospital LOS (median, CRS+HIPEC: 12 vs. CRS: 10, p = 0.019). While administration of HIPEC did not impact long-term survival (median OS, CRS+HIPEC: 16 months vs. CRS: 12 months, p = 0.55), postoperative complications (median OS, CCI < 30:16 months vs. CCI > 30:5 months, p = 0.024) and ICU stay (median OS, no ICU stay: 16 months vs. ICU stay: 5 months, p = 0.008) were associated with worsened long-term survival among GC patients with PM.

CONCLUSIONS

Data from the current study demonstrated a lack of survival benefit among advanced GC patients with PM undergoing gastrectomy with CRS+HIPEC when compared with individuals after gastrectomy with CRS alone. Administration of perioperative chemotherapy and achievement of TO failed to withstand the peritoneal disease progression during NAC.

Imaging lymph node regression can predict the pathological tumor regression grade in gastric cancer after neoadjuvant treatment

BACKGROUND

Neoadjuvant chemotherapy has become the standard treatment for locally advanced gastric cancer. The tumor regression grade system is an effective and widely used tool for the evaluation of treatment response to neoadjuvant chemotherapy. However, whether tumor regression grade could be predicted using clinical characteristics is uncertain.

METHODS

A total of 287 locally advanced gastric cancer patients from 2014 to 2021 were retrospectively included. According to the College of American Pathologists' tumor regression grade system, patients were classified into response group (tumor regression grade 0-1) and non-response group (tumor regression grade 2-3). Associations between clinical characteristics and neoadjuvant chemotherapy response were performed by the logistic regression model. The Kaplan-Meier method was used to estimate the survival. A prediction scoring system was constructed based on the β coefficients of multivariate analysis. The receiver operating characteristic curve and decision curve analysis were used to evaluate the performance of the predictive scoring system.

RESULTS

Survival analysis showed that patients with tumor regression grades 0 to 1 had significantly better disease-free survival and overall survival than the tumor regression grades 2 to 3. Tumor differentiation, ycT stage, immunotherapy, and lymph node regression were independent predictors of pathological response to neoadjuvant chemotherapy. We further developed a scoring system to predict the tumor regression grade. The receiver operating characteristic and decision curve analysis showed good predictive performance of the scoring system.

CONCLUSION

Lymph node regression could be used as a predictor for pathological response. We developed a scoring system to predict the treatment response of patients with gastric cancer receiving neoadjuvant chemotherapy. The scoring system based on the predictors could provide guidance for making clinical decisions.

Comparison of the predictive value of pathological response at primary tumor and lymph node status after neoadjuvant chemotherapy in locally advanced gastric cancer

BACKGROUND

Preoperative chemotherapy has been increasingly used in locally advanced gastric cancer (LAGC). However, the prognostic factors are still insufficient. This study aimed to investigate the prognostic significance of pathological response of the primary tumor to neoadjuvant chemotherapy (NACT) and the lymph node status after NACT.

METHODS

Data from 160 patients with LAGC treated with NACT followed by gastrectomy and met the inclusion criteria between March 2016 and December 2019 were retrospectively reviewed. Pathological evaluation after NACT was based on the grade of pathological response of the primary tumor and the status of lymph node. Survival curves for overall survival (OS) and disease-free survival (DFS) were estimated using the Kaplan-Meier method, and the log-rank test was used to compare survival difference. Univariate and multivariate analyses for prognostic factors were based on the Cox regression.

RESULTS

Among 160 selected cases, 90 had pathological response (PR), while 70 had no pathological response (nPR) to NACT. Smaller tumor size was presented in PR group, which also had lower level of signet ring cell features, compared to nPR group (all p < 0.05). Based on the status of lymph nodes, nodal status (-) group showed smaller tumor size, lower depth of tumor invasion, better differentiated degree, lower level of signet ring cell features, lower rate of lymphatic and venous invasion and less advanced ypTNM stage (all p < 0.05). Survival was equivalent between PR and nPR group (all p > 0.05), while patients with no lymph node metastasis had better DFS than that with lymph node metastasis (HR 0.301, 95% CI 0.194-0.468, p = 0.002). Multivariable Cox regression analysis identified that lymph node status after NACT was an independent prognostic factor associated with survival (OS: hazard ratio 1.756, 95% CI 1.114-3.278, p = 0.029; DFS: hazard ratio 1.901, 95% CI 1.331-3.093, p = 0.012).

CONCLUSION

Lymph node status is a potential independent prognostic factor for LAGC patients treated with NACT and may be more efficient than pathological response in primary tumor.

Significant Tumor Regression after Neoadjuvant Chemotherapy in Gastric Cancer, but Poor Survival of the Patient? Role of MHC Class I Alterations

We aimed to determine the clinical and prognostic relevance of allelic imbalance (AI) of the major histocompatibility complex (MHC) class I genes, encompassing the human leukocyte antigen (HLA) class I and beta-2 microglobulin (B2M) genes, in the context of neoadjuvant platinum/fluoropyrimidine chemotherapy (CTx). Biopsies before CTx were studied in 158 patients with adenocarcinoma of the stomach or gastroesophageal junction. The response was histopathologically evaluated. AI was detected by multiplex PCRs analysis of four or five microsatellite markers in HLA and B2M regions, respectively. AI with no marker was significantly associated with response or survival. However, subgroup analysis revealed differences. AI at marker D6S265, close to the HLA-A gene, was associated with an obvious increased risk in responding (HR, 3.62; 95% CI, 0.96-13.68, p = 0.058) but not in non-responding patients (HR, 0.92; 95% CI, 0.51-1.65, p = 0.773). Markers D6S273 and D6S2872 showed similar results. The interaction between AI at D6S265 and response to CTx was significant in a multivariable analysis (p = 0.010). No associations were observed for B2M markers. Our results underline the importance of intact neoantigen presentation specifically for responding patients and may help explain an unexpectedly poor survival of a patient despite significant tumor regression after neoadjuvant platinum/fluoropyrimidine CTx.

Intratumoral heterogeneity affects tumor regression and Ki67 proliferation index in perioperatively treated gastric carcinoma

BACKGROUND

Intratumoral heterogeneity (ITH) is a major problem in gastric cancer (GC). We tested Ki67 and tumor regression for ITH after neoadjuvant/perioperative chemotherapy.

METHODS

429 paraffin blocks were obtained from 106 neoadjuvantly/perioperatively treated GCs (one to five blocks per case). Serial sections were stained with Masson's trichrome, antibodies directed against cytokeratin and Ki67, and finally digitalized. Tumor regression and three different Ki67 proliferation indices (PI), i.e., maximum PI (KiH), minimum PI (KiL), and the difference between KiH/KiL (KiD) were obtained per block. Statistics were performed in a block-wise (all blocks irrespective of their case-origin) and case-wise manner.

RESULTS

Ki67 and tumor regression showed extensive ITH in our series (maximum ITH within a case: 31% to 85% for KiH; 4.5% to 95.6% for tumor regression). In addition, Ki67 was significantly associated with tumor regression (p < 0.001). Responders (<10% residual tumor, p = 0.016) exhibited prolonged survival. However, there was no significant survival benefit after cut-off values were increased ≥20% residual tumor mass. Ki67 remained without prognostic value.

CONCLUSIONS

Digital image analysis in tumor regression evaluation might help overcome inter- and intraobserver variability and validate classification systems. Ki67 may serve as a sensitivity predictor for chemotherapy and an indicator of ITH.