Novel avenues in immunotherapies for colorectal cancer

The Prognostic Significance of C-reactive Protein-To-Lymphocyte Ratio in Colorectal Liver Metastases

BACKGROUND

The preoperative systemic inflammation has been reported to predict tumor recurrence and survival in various cancers, including colorectal liver metastases (CRLM). However, more sensitive biomarker is required to improve perioperative management of CRLM. Therefore, we developed a novel indicator; C-reactive protein-to-lymphocyte ratio (CLR). The aim of this study is to evaluate the prognostic significance of CLR in patients with CRLM after hepatic resection.

MATERIALS AND METHODS

The study comprised 197 patients who had undergone hepatic resection for CRLM between January 2000 and December 2018. We retrospectively investigated the relation between CLR and disease-free survival and overall survival after hepatic resection and compared their prognostic significance with that of the C-reactive protein-to-albumin ratio and neutrophil-to-lymphocyte ratio.

RESULTS

Optimal cutoff level of the CLR by receiver operating characteristics analysis was 62.8 × 10^-6. By multivariate analysis, CLR was an independent predictor of disease-free survival [hazard ratio (HR): 1.463, 95% confidence interval (CI): 1.003-2.135, P = 0.048), whereas lymph node metastases>4 (HR: 1.804, 95% CI: 1.100-2.958, P = 0.019) and CLR (HR: 1.656, 95% CI: 1.007-2.724, P = 0.047) were independent predictors of overall survival, while the C-reactive protein-to-albumin ratio and neutrophil-to-lymphocyte ratio were not.

CONCLUSIONS

CLR may be an independent and significant indicator of poor long-term outcomes in patients with CRLM after hepatic resection.

Genomics and emerging biomarkers for immunotherapy of colorectal cancer

Colorectal cancer (CRC) is a common and lethal disease with a high therapeutic need. For most patients with metastatic CRC, chemotherapy is the only viable option. Currently, immunotherapy is restricted to the particular genetic subgroup of mismatch-repair deficient (MMRd)/microsatellite instable (MSI) CRC. Anti-PD1 therapy was recently FDA-approved as a second-line treatment in this subgroup. However, in a metastatic setting, these MMRd/MSI tumors are vastly outnumbered by mismatch-repair proficient (MMRp)/microsatellite stable (MSS) tumors. These MMRp/MSS tumors do not meaningfully respond to any traditional immunotherapy approach including checkpoint blockade, adoptive cell transfer and vaccination. This resistance to immunotherapy is due to a complex tumor microenvironment that counteracts antitumor immunity through a combination of poorly antigenic tumor cells and an immunosuppressive tumor microenvironment. To find ways of overcoming immunotherapy resistance in the majority of CRC patients, it is necessary to analyze the immunological makeup in an in-depth and personalized way and in the context of their tumor genetic makeup. Flexible, biomarker-guided early-phase immunotherapy trials are needed to optimize this workflow. In this review, we detail key mechanisms for immune evasion and emerging immune biomarkers for personalized immunotherapy in CRC. Also, we present a template for biomarker-guided clinical trials that are needed to move new immunotherapy approaches closer to clinical application.

The Immunogenicity of Colorectal Cancer in Relation to Tumor Development and Treatment

Although most cancer types have been viewed as immunologically silent until recently, it has become increasingly clear that the immune system plays key roles in the course of tumor development. Remarkable progress towards understanding cancer immunogenicity and tumor-immune system interactions has revealed important implications for the design of novel immune-based therapies. Natural immune responses, but also therapeutic interventions, can modulate the tumor phenotype due to selective outgrowth of resistant subtypes. This is the result of heterogeneity of tumors, with genetic instability as a driving force, and obviously changes the immunogenicity of tumors. In this review, we discuss the immunogenicity of colorectal cancer (CRC) in relation to tumor development and treatment. As most tumors, CRC activates the immune system in various ways, and is also capable of escaping recognition and elimination by the immune system. Tumor-immune system interactions underlie the balance between immune control and immune escape, and may differ in primary tumors, in the circulation, and in liver metastases of CRC. Since CRC immunogenicity varies between tumors and individuals, novel immune-based therapeutic strategies should not only anticipate the molecular profile, but also the immunological profile of a specific tumor.