Neoadjuvant Chemotherapy For Gastric Cancer Research Articles

A scoring system for indication of neoadjuvant chemotherapy in gastric cancer

A scoring system for indication of neoadjuvant chemotherapy in gastric cancer

The relationship between gastric microbiome features and responses to neoadjuvant chemotherapy in gastric cancer.

Emerging evidence demonstrates that the gastrointestinal microbiome has the potential to be a biomarker in neoadjuvant chemoradiotherapy for colorectal cancer (CRC). Yet studies on the impact of the gastric microbiome (GM) on the response to neoadjuvant chemotherapy (NACT) are still scarce. Forty-eight patients with gastric cancer participated in this retrospective study, and 16S rRNA sequencing was performed to evaluate formalin-fixed and paraffin-embedded (FFPE) tissue biospecimens and fresh-frozen tissues. In this study, 16 bacterial taxa at different levels, including Bacillus, Anaerococcus, and Chloroflexi, were identified to be enriched before NACT in response (R) patients in group FFPE. In contrast, 6 bacterial taxa, such as Haemophilus, Veillonellaceae (Veillonella), etc. were enriched after NACT, in which we reported for the first time that the phylum Chloroflexi was enriched before NACT in R patients. Thirty-one bacterial taxa of Coriobacteriaceae, Ruminococcaceae, Veillonellaceae, and Lachnospiraceae were identified in group mucosa as being enriched in R patients. In comparison, 4 bacterial taxa dominated by the phylum Proteobacteria were enriched in NR patients. Notably, the family Veillonellaceae was found in both tissue samples, and the metabolic pathways, including the citrate cycle (TCA cycle) and various amino acids, including alanine, were found to be potentially predictive in both sample species. There are differences in the features of the GM for different NACT response results. The causal relationship deserves to be confirmed by further investigations.

Metastatic Lymph Node 64 (MLN64) Expression in Gastric Cancer: The Clinical and Molecular Implications in Drug Resistance.

Metastatic lymph node 64 (MLN64) is often co-amplified with ERBB2 (HER2) and plays a role in the progression of breast and prostate cancer. The present study explored the expression of MLN64 in clinical gastric cancer in association with the ERBB family and its impact on drug resistance in patients. Two independent gastric cancer cohorts (n=324; n=87) were used to explore the expression profile of MLN64 in conjunction with ERBB family members in clinical gastric cancer and its association with neoadjuvant chemotherapy responses. Gastric cancer AGS and HCG27 cells with MLN64 knockdown were generated to determine the function of MLN64 in cell behavioural changes. Gastric tumor tissues expressed significantly higher levels of MLN64 compared with normal tissues (p<0.01); however, MLN64 alone was a weak prognostic indicator. An integrated co-expression of MLN64, ERBB4, and NRG4 was a significant factor in assessing overall survival in both cohorts. MLN64 was a profound indicator of patient response to neoadjuvant chemotherapy. In vitro studies indicated a significant contribution of MLN64 to the response of gastric cancer cells to chemodrugs and Her-2 inhibitors. MLN64 knockdown also contributed to the adhesion and migration and suggested a possible mechanism mediated by the interaction between MLN64 and ERBBs. MLN64 is an indicator of patient response to neoadjuvant chemotherapy in gastric cancer. Together with the expression pattern of ERBB4, MLN64 is a poor prognostic factor for patients with gastric cancer.

CT sarcometry in the prediction of postoperative complications in patients with gastric cancer: Retrospective cohort study

Aim. Computed tomographic preoperative assessment of sarcopenia in patients with gastric cancer as a part of combined treatment and the study of the relationship between sarcopenia and postoperative complications.&#x0D; Materials and methods. We analyzed retrospectively the data of 65 patients with morphologically verified diagnosis of stage IIA–IIIC gastric cancer. All patients at stage I of the combined treatment received neoadjuvant chemotherapy (NCT) according to the FLOT regimen, and then a gastrectomy with D2 lymph node dissection was performed. Computed tomography (CT) scans were performed before NCT initiation and 3.5 to 5 weeks after NCT completion for preoperative staging and assessment of tumor response. Using the obtained CT data, CT sarcometry was performed by calculating the cross-sectional area of skeletal muscles at the LIII vertebra level and the “skeletal-muscular index”. Postoperative complications were assessed using the Clavien–Dindo classification. Non-parametric comparison methods were used to assess the significance of differences between groups and subgroups (Wilcoxon T-test, Pearson χ2 test). Differences were considered statistically significant at p0.05.&#x0D; Results. We analyzed the incidence of sarcopenia in the examined patients before the NCT and immediately before the surgery. Sarcopenia was noted in 41 (63.1%) of 65 patients before NCT and in 50 (76.9%) patients after NCT, which indicates its high prevalence in patients with stomach cancer and the adverse effect of NCT on the muscular status of patients (76.9% versus 63.1%). Postoperative complications were diagnosed in 12 of 65 patients (18.5%). The rate of postoperative complications in patients with and without sarcopenia was not statistically significantly different (p=0.392); however, complications of Clavien–Dindo grade ≥IIIb occurred only in patients with sarcopenia (p0.001).&#x0D; Conclusion. According to our data, NCT in gastric cancer aggravates preoperative nutritional disorders. CT, as a standard method of staging and assessing the tumor response to NCT for gastric cancer, provides a tool to assess the state of muscle mass in patients before and after NCT. Preoperative sarcopenia is a risk factor for severe postoperative complications in patients with gastric cancer after gastrectomy.

ASO Visual Abstract: Patterns of Recurrence after Poor Response to Neoadjuvant Chemotherapy in Gastric Cancer and the Role for Adjuvant Radiation.

ASO Visual Abstract: Patterns of Recurrence after Poor Response to Neoadjuvant Chemotherapy in Gastric Cancer and the Role for Adjuvant Radiation.

Patterns of Failure for Poor Response to Neoadjuvant Chemotherapy in Gastric Cancer

Peri-operative chemotherapy has emerged as the standard of care in the treatment of locally advanced gastric cancer. Improved treatment strategies are needed for patients with a poor response to neoadjuvant chemotherapy and postoperative chemoradiation has been proposed as a potential method of treatment intensification. We aimed to describe the patterns of failure for patients with no or partial response (NR, PR) to pre-operative chemotherapy. We retrospectively reviewed charts of patients with locally advanced gastric cancer treated at our institution from 2008 to 2022 with pre-operative chemotherapy followed by surgery with a D2 resection. We excluded patients who received pre-operative or post-operative radiation therapy, or patients who had a complete response (CR) following neoadjuvant chemotherapy. Cumulative incidence of locoregional failure (LRF) and distant metastases (DM) were calculated from the time of diagnosis with competing risk analysis with death as a competing risk and censored at the last follow up. Overall survival (OS) was analyzed using Kaplan-Meier. A total of 57 patients were identified and 60% are male. Median follow-up time was 31.3 months (range 6.9-181.5 months), and the median age at diagnosis was 68 years old (range 30-86). The most used pre-operative chemotherapy regimen was FLOT (38.6%), followed by FOLFOX (29.8%), and ECF/ECX/EOX (19.3%), and a majority of patients (57.9%) received adjuvant chemotherapy. The most common histology was adenocarcinoma (85.9%), and 61.4% of patients had poorly differentiated disease. Thirty-three (57.9%), and 9 patients (15.8%) were characterized as PR and NR to neoadjuvant therapy by pathology, respectively. The distribution of pathologic stages following neoadjuvant chemotherapy were as follows: 17 patients (29.8%) with Stage IA-B, 12 patients (21.1%) with Stage IIA-B, 15 patients (26.3%) with Stage IIIA, 9 patients (15.8%) with Stage IIIB, and 3 patients (5.3%) with Stage IIIC disease. Two patients had positive lymph nodes with a T0 primary tumor. Median OS was 51.4 months (95% confidence interval [CI] 39.8-68.4) for the entire cohort, and 92.1 months (95% CI 34.6-73.0) versus 42.8 months (95% CI 23.1-88.0) for patients with a PR, and NR, respectively (p = 0.14). The 2-year cumulative incidence of LRF and DM was 7.4% (95% CI 0.4-14.3) and 36.3% (95% CI 23.6-49.1), respectively. Of the five patients who experienced LRF, three of the patients also eventually or concurrently developed DM. 60% of these patients would have had their first site of recurrence covered by standard post-operative radiation treatment volumes. Patients with locally advanced gastric cancer who do have less than a CR to chemotherapy have poor outcomes due to high rates of DM. Adjuvant locoregional therapy such as radiation is unlikely to affect survival while DM is the predominant pattern of progression. Further studies are needed to identify adjuvant therapies to improve distant control.

Patterns of Recurrence After Poor Response to Neoadjuvant Chemotherapy in Gastric Cancer and the Role for Adjuvant Radiation.

Improved treatment strategies are needed for patients with locally advanced gastric cancer with poor response to neoadjuvant chemotherapy. We aimed to describe patterns of failure for patients with no or partial response (NR, PR) to preoperative chemotherapy. We analyzed patients with locally advanced gastric cancer treated from 2008 to 2022 with preoperative chemotherapy followed by surgery with D2 resection. We excluded patients who received radiation. Cumulative incidence of locoregional failure (LRF) and distant metastases (DM) were calculated. For patients with recurrent abdominal disease, hypothetical radiation clinical treatment volumes (CTV) were contoured on postoperative scans and compared with patterns of recurrence. A total of 60 patients were identified. The most used preoperative chemotherapy was FLOT (38.6%), followed by FOLFOX (30%) and ECF/ECX/EOX (23.3%). Four (6.7%), 40 (66.7%), and 9 patients (15%) had a complete pathologic response (CR), PR, and NR to neoadjuvant therapy, respectively. Among patients without a CR, 3-year overall and progression-free survival rates were 62.3% (95% CI 48-76.6%) and 51.3% (95% CI 36.9-65.7%), respectively. Three-year cumulative incidence of LRF and DM were 8.4% (95% CI 0.4-16.4%) and 41.0% (95% CI 26.3-55.4%), respectively. Absolute rates of patients having the first site of recurrence encompassed by a postoperative radiation CTV was 2.0% for patients without a CR and 0% for patients with NR. Patients with locally advanced gastric cancer with less than a CR to chemotherapy have poor outcomes due to high rates of DM. Adjuvant locoregional therapy such as radiation is unlikely to affect survival.

Effect of home-based prehabilitation on postoperative complications after surgery for gastric cancer: randomized clinical trial.

Recent studies have demonstrated that prehabilitation improves patients' physical fitness but its impact on postoperative morbidity remains unclear. This study aimed to assess the effect of personalized, multimodal, semisupervised, home-based prehabilitation on postoperative complications after surgery for gastric cancer. This RCT was conducted at two centres in Lithuania. Patients (aged at least18 years) with gastric cancer scheduled to undergo elective primary surgery or surgery after neoadjuvant chemotherapy for gastric cancer were randomized (1 : 1) to prehabilitation or standard care. Prehabilitation included exercise interventions focused on endurance, respiratory muscle strength, stretching, and resistance training as well as nutritional and psychological support. The primary outcome was the proportion of patients with postoperative complications within 90 days after surgery. Secondary outcomes included 90-day mortality rate, physical condition, fitness level, nutritional status, quality of life, anxiety and depression level, and proportion of patients completing neoadjuvant chemotherapy. Between February 2020 and September 2022, 128 participants were randomized to prehabilitation (64) or standard care (64), and 122 (prehabilitation 61, control 61) were analysed. The prehabilitation group had increased physical capacity before the operation compared with baseline (mean 6-min walk test change +31 (95 per cent c.i. 14 to 48) m; P = 0.001). The prehabilitation group had a decreased rate of non-compliance with neoadjuvant treatment (risk ratio (RR) 0.20, 95 per cent c.i. 0.20 to 0.56), a 60 per cent reduction in the number of patients with postoperative complications at 90 days after surgery (RR 0.40, 0.24 to 0.66), and improved quality of life compared with the control group. Prehabilitation reduced morbidity in patients who underwent gastrectomy for gastric cancer. NCT04223401 (http://www.clinicaltrials.gov).

Value of spectral CT parameters in predicting the efficacy of neoadjuvant chemotherapy for gastric cancer

To investigate the value of pre-chemotherapy spectral computed tomography (CT) parameters in predicting neoadjuvant chemotherapy (NAC) response in gastric cancer (GC). Sixty patients with GC who received NAC and underwent spectral CT examination before chemotherapy were enrolled retrospectively and divided into a responsive group and a non-responsive group according to the postoperative pathological tumour regression grade. Clinical characteristics were collected. The iodine concentration (IC), water concentration (WC), and effective atomic number (Eff-Z) of the portal venous phases were measured before chemotherapy, and IC was normalised to that of the aorta to provide the normalised IC (NIC). An independent samples t-test, Mann-Whitney U-test, or chi-square test was used to analyse the differences between the two groups, and the receiver operating curve (ROC) was used to evaluate the predictive performance of different variables. The neutrophil-to-lymphocyte ratio (NLR) was lower in the responsive group than in the non-responsive group (p<0.05). IC, NIC, and Eff-Z values were significantly higher in the responsive group than in the non-responsive group (p<0.01). The areas under the ROC curves for the NLR, IC, NIC, and Eff-Z were 0.694, 0.688, 0.799, and 0.690, respectively. The combination of NIC, Eff-Z, and NLR values showed good diagnostic performance in predicting response to NAC in GC, with an area under the ROC curve of 0.857, 76.92% sensitivity, 80% accuracy, and 85.71% specificity. Spectral CT parameters may serve as non-invasive tools for predicting the response to NAC in patients with GC.

TRG-High/ATM-Expressed/SIRT1-Absent Profile as Negative Prognostic Marker after Neoadjuvant Chemotherapy for Gastric Cancer

TRG-High/ATM-Expressed/SIRT1-Absent Profile as Negative Prognostic Marker after Neoadjuvant Chemotherapy for Gastric Cancer

Neoadjuvant Chemotherapy is Associated With Decreased Survival in Early-Stage Gastric Cancer.

Although randomized controlled trials on neoadjuvant chemotherapy for gastric cancer have included some T1-staged tumors, overall survival (OS) has not been analyzed for this subset. Due to the low negative predictive value of clinical staging and the benefits of neoadjuvant chemotherapy for locally advanced disease, identifying patient groups with early-stage gastric cancer that may benefit from neoadjuvant chemotherapy is of merit. The objective of this study was to evaluate the relationship between OS and sequence of surgical therapy for clinical T1 gastric cancer. The 2017 National Cancer Database was used to compare patients who had surgery-first and those who received neoadjuvant chemotherapy for T1-stage gastric cancer. OS was analyzed using a parametric regression survival-time model adjusted for covariates. The effects of these covariates on OS based on surgical sequence were examined. 11,219 patients were included, of which 10,191 underwent surgery as their first or only treatment. When adjusted for covariates, neoadjuvant chemotherapy followed by curative-intent surgery was significantly associated with increased risk of death (HR 1.15, 95% CI 1.01-1.31, P = .030). In multivariate analysis, clinical N0 stage, non-minorities, and patients with high socioeconomic status had improved OS if they did not have neoadjuvant chemotherapy and instead had upfront surgery. Neoadjuvant chemotherapy is associated with decreased OS for early-stage gastric adenocarcinoma, even for patients with clinically positive nodal disease. In addition, the lack of survival improvement with a surgery-first approach in patients with disparities deserves further study.

Prognostic Model of D2 Radical Gastrectomy Combined with Neoadjuvant Chemotherapy for Gastric Cancer.

The AJCC (the American Joint Committee on Cancer) ypTNM (post-neoadjuvant pathologic stage group) staging was established based on patients with lymphadenectomy scope less than D2 and did not include ypT0N0 patients with pathologically complete response (PCR). The purpose of this study was to construct a survival predictive model for gastric cancer patients after neoadjuvant chemotherapy and gastrectomy combined with D2 lymphadenectomy. The multicenter data of 838 gastric cancer patients who received neoadjuvant chemotherapy and gastrectomy combined with D2 lymphadenectomy were analyzed retrospectively. These dual center patients were divided into training (n = 671, the Affiliated Hospital of Qingdao University) and validation (n = 167, Qingdao West Coast New Area Central Hospital) cohorts. Based on training cohort, univariate and multivariable COX regression analyses were performed to select the clinicopathological characteristics significantly correlating with overall survival and construct a nomogram. Based on training and validation cohorts, the distinguishing and calibrating capabilities of nomogram was evaluated by the receiver operating characteristic (ROC) curve, Harrell's concordance index (C-index), decision curve analysis (DCA) curve and calibration curve. Platelet-to-lymphocyte ratio (PLR), pathologic stage after neoadjuvant treatment: ypT and ypN stage, tumor regression grade (TRG) became independent variables intimately related to the prognosis and was used to construct nomograms of 3/5-year prognosis. The nomograms showed an accuracy in predicting OS (overall survival) rate, with area under the ROC curve (AUC) of 0.818 (95% CI = 0.753~0.883) and C-index of 0.801 (95% CI = 0.744~0.858) in validation cohort. Calibration curves showed satisfactory agreement between nomogram prediction and actual result, and DCA curves indicated the large positive net benefit and excellent clinical usefulness of nomogram. This study successfully developed a nomogram to predict overall survival of gastric cancer patients after neoadjuvant chemotherapy and gastrectomy combined with D2 lymphadenectomy, which might have excellent predictive performance and clinical application value.

ASO Author Reflections: The Prognostic Value of Pathologic Complete Response After Neoadjuvant Chemotherapy in Gastric Cancer.

ASO Author Reflections: The Prognostic Value of Pathologic Complete Response After Neoadjuvant Chemotherapy in Gastric Cancer.

Perioperative versus total neoadjuvant chemotherapy in gastric cancer.

Perioperative chemotherapy is standard of care management for locally advanced gastric cancer (GC), but a substantial proportion of patients do not complete adjuvant therapy due to postoperative complications and prolonged recovery. Administration of all chemotherapy prior to surgery in the form of total neoadjuvant therapy (TNT) may optimize complete delivery of systemic therapy. We performed a retrospective review of GC patients who had surgery at Memorial Sloan Kettering Cancer Center (MSKCC) from May 2014 to June 2020. One hundred and forty-nine patients were identified; 121 patients received perioperative chemotherapy and 28 patients received TNT. TNT was chosen if patients had interim radiographic and/or clinical response to treatment. Baseline characteristics were well-balanced between the two group except for chemotherapy regimen; more TNT patients received FLOT compared to the perioperative group (79% vs. 31%). There was no difference in the proportion of patients who completed all planned cycles, but TNT patients received a higher proportion of cycles containing all chemotherapy drugs (93% vs. 74%, P<0.001). Twenty-nine patients (24%) in the perioperative group did not receive intended adjuvant therapy. There was no significant difference in hospital length of stay or surgical morbidity. The overall distribution of pathologic stage was similar between the two groups. Fourteen percent of TNT patients and 5.8% of perioperative patients achieved a pathologic complete response (P=0.6). There was no significant difference in recurrence free survival (RFS) or overall survival (OS) between the TNT and perioperative groups [24-month OS rate 77% vs. 85%, HR 1.69 (95% CI: 0.80-3.56)]. Our study was limited by a small TNT sample size and biases inherent to a retrospective analysis. TNT appears to be feasible in a select population, without any increase in surgical morbidity.

Levels of oxidative stress in patients with neoadjuvant chemotherapy for gastric cancer: correlation with treatment response.

The intent of this study was to investigate the relationship between oxidative stress and treatment response in gastric cancer patients undergoing neoadjuvant chemotherapy. Blood samples from 108 patients and 108 healthy subjects were collected, and all patients were enrolled in SOX chemotherapy. The patients received four cycles of neoadjuvant chemotherapy. Blood samples were collected to determine oxidative stress levels at baseline prior to beginning chemotherapy, and at the end of cycles 2 and 4. The patients receiving neoadjuvant chemotherapy were followed up for several months to years. A survival curve was created according to the follow-up information from the patients. In addition, the correlation between oxidative stress level and treatment effect was evaluated and ROC curves were plotted according to the final collected data. Compared with the normal group, the levels of the antioxidant index decreased while the peroxide index increased in the patients. Conversely, when patients were compared before and after chemotherapy, the antioxidant index increased but the peroxide index decreased. Furthermore, the antioxidant index increased in the response group while the peroxide index decreased in the non-response group. Patients with an increased antioxidant index after chemotherapy have good treatment responsiveness. These indicators can also be used as predictors to judge the patients' response to chemotherapy.

Response Evaluation after Neoadjuvant Chemotherapy for Resectable Gastric Cancer

Background: The method of response evaluation following neoadjuvant chemotherapy (NAC) in resectable gastric cancer has been widely debated. An essential prerequisite is the ability to stratify patients into subsets of different long-term survival rates based on the response mode. Histopathological measures of regression have their limitations, and interest resides in CT-based methods that can be used in everyday settings. Methods: We conducted a population-based study (2007–2016) on 171 consecutive patients with gastric adenocarcinoma who were receiving NAC. Two methods of response evaluation were investigated: a strict radiological procedure using RECIST (downsizing), and a composite radiological/pathological procedure comparing the initial radiological TNM stage to the pathological ypTNM stage (downstaging). Clinicopathological variables that could predict the response were searched for, and correlations between the response mode and long-term survival rates were assessed. Results: RECIST failed to identify half of the patients progressing to metastatic disease, and it was unable to assign patients to subsets with different long-term survival rates based on the response mode. However, the TNM stage response mode did achieve this objective. Following re-staging, 48% (78/164) were downstaged, 15% (25/164) had an unchanged stage, and 37% (61/164) were upstaged. A total of 9% (15/164) showed a histopathological complete response. The 5-year overall survival rate was 65.3% (95% CI 54.7–75.9%) for TNM downstaged cases, 40.0% (95% CI 20.8–59.2%) for stable disease, and 14.8% (95% CI 6.0–23.6%) for patients with TNM progression, p &lt; 0.001. In a multivariable ordinal regression model, the Lauren classification and tumor site were the only significant determinants of the response mode. Conclusions: Downsizing, as a method for evaluating the response to NAC in gastric cancer, is discouraged. TNM re-staging by comparing the baseline radiological CT stage to the pathological stage following NAC is suggested as a useful method that may be used in everyday situations.

Aspartate β-Hydroxylase Serves as a Prognostic Biomarker for Neoadjuvant Chemotherapy in Gastric Cancer

Neoadjuvant chemotherapy (NACT) has been established as being an effective treatment for advanced gastric cancer (GC), while the predictive biomarker of NACT efficacy remains under investigation. Aspartate β-hydroxylase (ASPH) represents an attractive target which is a highly conserved transmembrane enzyme overexpressed in human GC, and participates in the malignant transformation by promoting tumor cell motility. Here, we evaluated the expression of ASPH by immunohistochemistry in 350 GC tissues (including samples for NACT) and found that ASPH expression was higher in patients undergoing NACT compared with patients without NACT pre-operation. The OS and PFS time of ASPH-intensely positive patients was significantly shorter than that of the negative patients in the NACT group, while the difference was not significant in patients without NACT. We showed that ASPH knockout enhanced the inhibitory effects of chemotherapeutic drugs on the cell proliferation, migration, and invasion in vitro and suppressed tumor progression in vivo. Co-immunoprecipitation revealed that ASPH might interact with LAPTM4B to perform chemotherapeutic drug resistance. Our results suggested that ASPH might serve as a candidate biomarker to predict prognosis and a novel therapeutic target for gastric cancer patients treated with neoadjuvant chemotherapy.

Increased CD4/CD8 Lymphocyte ratio predicts favourable neoadjuvant treatment response in gastric cancer: A prospective pilot study.

Despite optimal neoadjuvant chemotherapy only 40% of gastric cancer tumours achieve complete or partial treatment response. In the absence of treatment response, neoadjuvant chemotherapy in gastric cancer contributes to adverse events without additional survival benefit compared to adjuvant treatment or surgery alone. Additional strategies and methods are required to optimize the allocation of existing treatment regimens such as FLOT chemotherapy (5-Fluorouracil, Leucovorin, Oxaliplatin and Docetaxel). Predictive biomarkers detected using immunohistochemistry (IHC) methods may provide useful data regarding treatment response. To investigate the utility of CD4, CD8, Galectin-3 and E-cadherin in predicting neoadjuvant FLOT chemotherapy tumour response in gastric adenocarcinoma. Forty-three adult patients with gastric adenocarcinoma, of which 18 underwent neoadjuvant chemotherapy, were included in a prospective clinical cohort. Endoscopic biopsies were obtained from gastric cancer and normal adjacent gastric mucosa. Differences in expression of Galectin-3, E-cadherin, CD4+ and CD8+ molecules between tumours with and without treatment response to neoadjuvant chemotherapy were assessed with IHC. Treatment response was graded by clinical pathologists using the Tumour Regression Score according to the College of American Pathologists criteria. Treatment response was defined as complete or near complete tumour response, whereas partial or poor/no response was defined as incomplete. Digital IHC images were annotated and quantitatively assessed using QuPath 0.3.1. Biomarker expression between responsive and incomplete response tumours was assessed using a two-sided Wilcoxon test. Biomarker expression was also compared between normal and cancer tissue and between 15 paired tumour samples before and after chemotherapy. We performed a preliminary multivariate analysis and power analysis to guide future study. Statistical analyses were completed using R 4.1.2. The ratio between CD4+ and CD8+ lymphocytes was significantly greater in treatment responsive tumours (Wilcoxon, P = 0.03). In univariate models, CD4+/CD8+ ratio was the only biomarker that significantly predicted favourable treatment response (Accuracy 86%, P < 0.001). Using a glmnet multivariate model, high CD4+/CD8+ ratio and low Galectin-3 expression were the most influential variables in predicting a favourable treatment response. Analyses of paired samples found that FLOT chemotherapy also results in increased expression of CD4+ and CD8+ tumour infiltrating lymphocytes (Paired Wilcoxon, P = 0.002 and P = 0.008, respectively). Our power analysis suggests future study requires at least 35 patients in each treatment response group for CD8 and Galectin-3 molecules, whereas 80 patients in each treatment response group are required to assess CD4 and E-cadherin biomarkers. We demonstrate that an elevated CD4+/CD8+ Ratio is a promising IHC-based biomarker to predict favourable treatment response to FLOT neoadjuvant chemotherapy in locally advanced gastric cancer.

The optimal extent of lymph node dissection for gastric cancer with para-aortic lymph node metastases.

413 Background: Gastric cancer (GC) with para-aortic lymph node (PAN) metastasis is diagnosed as stage IV and basically treated with chemotherapy. Recently, D2 and PAN dissection after neoadjuvant chemotherapy (NAC) was reportedly effective when PAN metastasis was limited within #16a2/b1 area. However, PAN dissection is highly invasive surgical procedure and it still remains unclear whether PAN dissection contributes to the survival for these tumors. This study aimed to determine the optimal extent of lymph node dissection for these tumors focusing on survival benefit of PAN dissection. Methods: The study examined patients who received radical gastrectomy with D2 and PAN dissection after NAC for gastric cancer with PAN metastasis (#16a2/b1) from 2004 to 2015. Survival benefit of lymph node dissection was estimated using therapeutic value index (TI). TI was calculated by multiplication of incidence of metastasis and 5-year survival rate of patients with metastasis for each lymph node area. TI of D2 dissection area (TI-D2) and PAN area (TI-PAN) was calculated separately. Overall survival (OS) was calculated in patients who had metastasis to PAN pathologically after surgery (pPAN+ group) and those who had not (pPAN- group). The recurrence site was also examined. Results: Thirty-two patients were analyzed. TI-D2 and TI-PAN were 15.6 and 0.0, respectively. 5y-OS was 81.0% in pPAN- group (21 cases) but was 0.0% in pPAN+ group (11 cases). The most frequent recurrence site was the lymph nodes (82.4% of all recurrences). Among lymph node recurrence, almost all recurrence patterns included the PANs (85.7% of lymph node recurrence). Conclusions: The prognosis was extremely poor when tumor cells remained on PAN after NAC. In these cases, PAN recurrence was seen most frequently even after PANs had been dissected. Patients with PAN could have the chance for the cure only when tumor cells on PAN was completely eliminated by NAC. It is unclear whether they actually needed PAN dissection for pathologically negative PAN. The optimal extent of lymph node dissection after NAC might be D2 for GC with PAN metastasis.

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.