Prognosis and chemosensitivity of non-colorectal alimentary tract cancers with microsatellite instability

Perioperative chemotherapy for gastric cancer patients with microsatellite instability or deficient mismatch repair: A systematic review and meta-analysis

BACKGROUND

The efficacy of perioperative chemotherapy for deficient mismatch repair or microsatellite instability-high (dMMR/MSI-H) gastric cancer (GC) remains controversial.

METHODS

This study was preregistered with the PROSPERO platform (CRD42023494276), and studies comparing perioperative chemotherapy with surgery alone in resectable dMMR/MSI-H GC were included. Hazard ratios (HRs) and their 95% confidence intervals (CIs) of survival outcomes were extracted. A random-effects model was used in the pooled analysis.

RESULTS

Twenty-two studies, which encompassed approximately 1600 patients with dMMR/MSI-H GC, were included. The results indicated that perioperative chemotherapy does not significantly improve overall survival (OS) (HR, 0.85; 95% CI, 0.58-1.26) and disease-free survival (DFS) (HR, 0.77; 95% CI, 0.53-1.12) in dMMR/MSI-H GC. In the subgroup analysis, adjuvant chemotherapy was not associated with improved OS (HR, 0.83; 95% CI, 0.50-1.37) but was associated with improved DFS (HR, 0.64; 95% CI, 0.43-0.96). However, the benefit of adjuvant chemotherapy for DFS was not significant in the pooled analysis of multivariable-adjusted results. Similar results were observed for neoadjuvant chemotherapy (OS: HR, 0.84; 95% CI, 0.44-1.57; DFS: HR, 1.13; 95% CI, 0.50-2.53). Additionally, stage stratification analysis demonstrated no significant survival benefit of adjuvant chemotherapy for stage II (OS: HR, 0.77; 95% CI, 0.31-1.90) or stage III (OS: HR, 0.72; 95% CI, 0.36-1.46) dMMR/MSI-H GC.

CONCLUSIONS

Despite indications that adjuvant chemotherapy may improve DFS in the subgroup analysis, this benefit was not sustained in multivariate assessments. Overall, the pooled results indicate that perioperative chemotherapy does not significantly improve OS or DFS in patients with resectable dMMR/MSI-H GC, and therefore such treatment may be spared in these patients.

A multicenter study evaluating efficacy of immune checkpoint inhibitors in advanced non-colorectal digestive cancers with microsatellite instability

BACKGROUND

One randomized phase III trial comparing chemotherapy (CT) with immune checkpoint inhibitors (ICI) has demonstrated significant efficacy of ICI in deficient DNA mismatch repair system/microsatellite instability-high (dMMR/MSI-H) metastatic colorectal cancer. However, few studies have compared ICI with CT in other advanced dMMR/MSI-H digestive tumors.

METHODS

In this multicenter study, we included patients with advanced dMMR/MSI-H non-colorectal digestive tumors treated with chemotherapy and/or ICIs. Patients were divided retrospectively into two groups, a CT group and an immunotherapy (IO) group. The primary endpoint was progression-free survival (PFS). A propensity score approach using the inverse probability of treatment weighting (IPTW) method was applied to deal with potential differences between the two groups.

RESULTS

133 patients (45.1/27.1/27.8% with gastric/small bowel/other carcinomas) were included. The majority of patients received ICI in 1st (29.1%) or 2nd line (44.4%). The 24-month PFS rates were 7.9% in the CT group and 71.2% in the IO group. Using the IPTW method, IO treatment was associated with better PFS (HR=0.227; 95% CI 0.147-0.351; p < 0.0001). The overall response rate was 26.3% in the CT group versus 60.7% in the IO group (p < 0.001) with prolonged duration of disease control in the IO group (p < 0.001). In multivariable analysis, predictive factors of PFS for patients treated with IO were good performance status, absence of liver metastasis and prior primary tumor resection, whereas no association was found for the site of the primary tumor.

CONCLUSIONS

In the absence of randomized trials, our study highlights the superior efficacy of ICI compared with standard-of-care therapy in patients with unresectable or metastatic dMMR/MSI-H non-colorectal digestive cancer, regardless of tumor type, with acceptable toxicity.

Neoadjuvant and/or adjuvant chemotherapy for gastric cancer patients with microsatellite instability or deficient mismatch repair: a systematic review and meta-analysis study protocol

INTRODUCTION

Whether gastric cancer (GC) patients with deficient mismatch repair or microsatellite instability-high (dMMR/MSI-H) benefit from perioperative (neoadjuvant and/or adjuvant) chemotherapy is controversial. This protocol delineates the planned scope and methods for a systematic review and meta-analysis that aims to compare the efficacy of perioperative chemotherapy with surgery alone in resectable dMMR/MSI-H GC patients.

METHODS AND ANALYSIS

This study protocol is reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocols-P guideline. PubMed, Embase, Cochrane (CENTRAL), and the Web of Science databases will be searched, supplemented by a secondary screening of relevant records. Both randomised controlled trials and non-randomised studies will be included in this study. The primary and secondary outcomes under scrutiny will be overall survival, disease-free survival and progression-free survival. Two reviewers will independently screen studies, extract data and assess the risk of bias. We will analyse different treatment settings (eg, neoadjuvant or adjuvant or combined as perioperative chemotherapies) separately and conduct sensitivity analyses.

ETHICS AND DISSEMINATION

No ethics approval is required for this systematic review and meta-analysis, as no individual patient data will be collected. The findings of our study will be published in a peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42023494276.

Mismatch repair deficiency as prognostic factor for stage III small bowel adenocarcinoma: A multicentric international study

BACKGROUND

Small bowel adenocarcinoma (SBA) is a rare cancer with an aggressive behavior. No study has specifically addressed the putative prognostic role of mismatch repair status in stage III SBAs.

AIMS

We aimed to investigate whether mismatch repair deficiency is associated with cancer-specific survival in a Western cohort of patients with stage III SBAs.

METHODS

In this retrospective multicentric international cohort study, we enrolled 70 patients who underwent surgically resection for stage III SBAs and we analyzed the frequency of mismatch repair deficiency, tested by immunohistochemistry for mismatch repair proteins and by polymerase chain reaction for microsatellite instability, and its association with cancer-specific survival and other clinic-pathologic factors.

RESULTS

We found sixteen (23%) patients with mismatch repair deficient adenocarcinoma, without discordance between immunohistochemical and polymerase chain reaction for microsatellite instability analyses. Mismatch repair deficiency proved to be associated with a better outcome both at univariable analysis (hazard ratio: 0.28, 95% confidence interval: 0.08-0.91, p: 0.035) and in bivariable models adjusted for patient age or gender, tumor site, pT4 stage, tumor budding, and perineural invasion.

CONCLUSION

This study highlights the importance of testing mismatch repair status to improve prognostic stratification in stage III SBAs.

Pattern of recurrence and overall survival in esophagogastric cancer after perioperative FLOT and clinical outcomes in MSI-H population: the PROSECCO Study

BACKGROUND

FLOT regimen is the standard perioperative treatment in Western countries for patients with locally advanced gastric (GC) or gastroesophageal junction cancer (GEJC). High microsatellite instability (MSI-H) and Mismatch Repair deficient (dMMR) demonstrated a favorable prognostic role and a concomitant negative predictive impact on the benefit of perioperative 5-fluorouracil-based doublets; however, its role in pts receiving FLOT chemotherapy is still unclear.

METHODS

This is a retrospective, multicenter observational study of 265 pts with GC/GEJC treated with perioperative FLOT regimen in 11 Italian oncology centers between January 2017 to December 2021 and analyzed for microsatellite status.

RESULTS

The MSI-H phenotype was found in 27 (10.2%) of 265 analyzed tumors. Compared to microsatellite stable (MSS) and Mismatch Repair proficient (pMMR) cases, MSI-H/dMMR were more frequently female (48.1% vs. 27.3%, p = 0.0424), elderly pts (age > 70 years, 44.4% vs. 13.4%, p = 0.0003), Laurens's intestinal type (62.5% vs. 36.1%, p = 0.02) and pts with a primary location tumor in the antrum (37 vs. 14.3%, p = 0.0004). A statistically significant difference in the rate of pathologically negative lymph node emerged (63% vs 30.7%, p = 0.0018). Compared to the MSS/pMMR tumor population, the MSI-H/dMMR subgroup had a better DFS (median not reached [NR] vs. 19.5 [15.59-23.59] mos, p = 0.031) and OS (median NR vs. 34.84 [26.68-47.60] mos, p = 0.0316).

CONCLUSIONS

These real-world data confirm that FLOT treatment is effective in daily clinical practice for locally advanced GC/GEJC, also in the MSI-H/dMMR subgroup. It also showed a higher rate of nodal status downstaging and a better outcome of MSI-H/dMMR pts in comparison to MSS/pMMR.