Treatment Efficacy of Immune Checkpoint Inhibitors for Patients with Advanced or Metastatic Colorectal Cancer: A Systematic Review and Meta-Analysis

Immune checkpoint inhibitors in gastrointestinal malignancies: an Umbrella review

In the Modern era, immune checkpoint inhibitors (ICIs) have been the cornerstone of success in the treatment of several malignancies. Despite remarkable therapeutic advances, complex matrix together with significant molecular and immunological differences have led to conflicting outcomes of ICI therapy in gastrointestinal (GI) cancers. As far we are aware, to date, there has been no study to confirm the robustness of existing data, and this study is the first umbrella review to provide a more comprehensive picture about ICIs' efficacy and safety in GI malignancies. Systematic search on PubMed, Scopus, Web of Science, EMBASE, and Cochrane library identified 14 meta-analyses. The pooled analysis revealed that ICIs application, especially programmed death-1 (PD-1) inhibitors such as Camrelizumab and Sintilimab, could partially improve response rates in patients with GI cancers compared to conventional therapies. However, different GI cancer types did not experience the same efficacy; it seems that hepatocellular carcinoma (HCC) and esophageal cancer (EC) patients are likely better candidates for ICI therapy than GC and CRC patients. Furthermore, application of ICIs in a combined-modal strategy are perceived opportunity in GI cancers. We also assessed the correlation of PD-L1 expression as well as microsatellite status with the extent of the response to ICIs; overall, high expression of PD-L1 in GI cancers is associated with better response to ICIs, however, additional studies are required to precisely elaborate ICI responses with respect to microsatellite status in different GI tumors. Despite encouraging ICI efficacy in some GI cancers, a greater number of serious and fatal adverse events have been observed; further highlighting the fact that ICI therapy in GI cancers is not without cost, and further studies are required to utmost optimization of this approach in GI cancers.

Association Between Intraoperative Dexamethasone and Postoperative Mortality in Patients Undergoing Oncologic Surgery: A Multicentric Cohort Study

OBJECTIVE

We examined the effects of dexamethasone on postoperative mortality, recurrence-free survival, and side effects in patients undergoing oncologic operations.

BACKGROUND

Dexamethasone prevents nausea and vomiting after anesthesia and may affect cancer proliferation.

METHODS

A total of 30,561 adult patients undergoing solid cancer resection between 2005 and 2020 were included. Multivariable logistic regression was applied to investigate the effect of dexamethasone on 1-year mortality and recurrence-free survival. Effect modification by the cancer's potential for immunogenicity, defined as a recommendation for checkpoint inhibitor therapy based on the National Comprehensive Cancer Network guidelines, was investigated through interaction term analysis. Key safety endpoints were dexamethasone-associated risk of hyperglycemia >180 mg/dL within 24 hours and surgical site infections within 30 days after surgery.

RESULTS

Dexamethasone was administered to 38.2% (11,666/30,561) of patients (6.5±2.3 mg). Overall, 3.2% (n=980/30,561) died and 15.4% (n=4718/30,561) experienced cancer recurrence within 1 year of the operation. Dexamethasone was associated with a -0.6% (95% confidence interval: -1.1, -0.2, P =0.007) 1-year mortality risk reduction [adjusted odds ratio (OR adj ): 0.79 (0.67, 0.94), P =0.009; hazard ratio=0.82 (0.69, 0.96), P =0.016] and higher odds of recurrence-free survival [OR adj : 1.28 (1.18, 1.39), P <0.001]. This effect was only present in patients with solid cancers who were defined as not to respond to checkpoint inhibitor therapy [OR adj : 0.70 (0.57, 0.87), P =0.001 vs OR adj : 1.13 (0.85, 1.50), P =0.40]. A high (>0.09 mg/kg) dose of dexamethasone increased the risk of postoperative hyperglycemia [OR adj : 1.55 (1.32, 1.82), P <0.001], but not for surgical site infections [OR adj : 0.84 (0.42, 1.71), P =0.63].

CONCLUSIONS

Dexamethasone is associated with decreased 1-year mortality and cancer recurrence in patients undergoing surgical resection of cancers that are not candidates for immune modulators. Dexamethasone increased the risk of postoperative hyperglycemia, however, no increase in surgical site infections was identified.

B7H4 Expression Is More Frequent in MSS Status Colorectal Cancer and Is Negatively Associated with Tumour Infiltrating Lymphocytes

The immunotherapies based on ICIs in CRC are nowadays limited to microsatellite unstable tumours which are approximately 15% of all CRC cases. There are a few new immune checkpoints belonging to the B7 family, including B7H4. B7H4 expression is associated with so-called “cold tumours”, and its function is linked to the downregulation of various immune cell populations. Our study aimed to investigate whether B7H4 expression is dependent on microsatellite status in CRC and on elucidating the immunological context in which the expression of B7H4 occurs. We enrolled 167 patients in the study. We prepared the homogenates from tumour tissues and healthy adjacent tissue to assess the B7H4 levels and the Bio-Plex Pro Human 48-cytokine panel. We assessed the microsatellite status of the tumour, B7H4 expression, CD8+ T cell population, and the TILs and budding in H + E stained slides by the IHC method. We used an online available database for further exploring the biological characteristics of B7H4. The expression of B7H4 was more frequent in microsatellite stable tumours, and was negatively associated with TILs. B7H4 is positively correlated with antitumour immunosuppressive iTME, thus contributing to the immunosuppressive environment in CRC.

Immunotherapy as a Therapeutic Strategy for Gastrointestinal Cancer-Current Treatment Options and Future Perspectives

Gastrointestinal (GI) cancer constitutes a highly lethal entity among malignancies in the last decades and is still a major challenge for cancer therapeutic options. Despite the current combinational treatment strategies, including chemotherapy, surgery, radiotherapy, and targeted therapies, the survival rates remain notably low for patients with advanced disease. A better knowledge of the molecular mechanisms that influence tumor progression and the development of optimal therapeutic strategies for GI malignancies are urgently needed. Currently, the development and the assessment of the efficacy of immunotherapeutic agents in GI cancer are in the spotlight of several clinical trials. Thus, several new modalities and combinational treatments with other anti-neoplastic agents have been identified and evaluated for their efficiency in cancer management, including immune checkpoint inhibitors, adoptive cell transfer, chimeric antigen receptor (CAR)-T cell therapy, cancer vaccines, and/or combinations thereof. Understanding the interrelation among the tumor microenvironment, cancer progression, and immune resistance is pivotal for the optimal therapeutic management of all gastrointestinal solid tumors. This review will shed light on the recent advances and future directions of immunotherapy for malignant tumors of the GI system.