The prognostic ability of immunoscore in predicting outcomes in patients with localized colon cancer: A systematic review and meta-analysis

Assessment of tumor recurrence risk as well as prognosis in resectable colon cancer are still mainly based on the histopathological criteria of tumor invasion reflected in the TNM classification. Robust data in colorectal tumor research show the value of tumor microenvironment and tumor-infiltrating lymphocytes (TILs) as novel parameters to predict recurrence and survival. The utility of the derived tumor Immunoscore via digital pathology is now being promoted to refine the prognosis of early colon cancer patients together with the TNM staging to guide treatment decisions, but is not yet a recommendation in international consensus guidelines. This study assessed the prognostic value of this diagnostic tool in predicting clinical outcomes.

A systematic literature search using PubMed, Embase, and Cochrane CENTRAL Library was conducted to identify observational or randomized controlled studies from January 2008 and December 2022 according to pre- specified inclusion and exclusion criteria which examined the relationship between Immunoscore and long-term prognosis (overall survival and disease free survival) in patients with localized colon cancer. Hazard ratios with 95% confidence interval for overall survival (OS) and disease-free survival (DFS) were extracted. Pooled estimates of the prognostic ability of immunoscore were obtained using bi-variate random effects model. Statistical heterogeneity between studies was evaluated with I2 statistics and explored through sensitivity analysis.

A total of 5,718 patients from 11 studies were included in the meta-analysis. Moderate heterogeneity between studies for both DFS (I2= 27%) and OS (I2= 33%) was seen. The pooled analysis indicated that compared to those with high Immunoscore, colon cancer patients with low Immunoscore were associated with shorter disease-free survival (HR 1.75, 95% CI 1.53 - 2.49) and overall survival (HR 1.87 95% CI 1.45 – 2.13). In the subgroup analyses, this association was consistent across geographic regions and maximum time of follow up.

A low immunoscore was significantly associated with poorer clinical outcomes in terms of disease-free survival and overall survival. The use of Immunoscore provides valuable estimate of the risk of recurrence in patients with early colon cancer and has the potential to greatly affect treatment decisions in conjunction with the existing risk assessment system.

The authors.

Has not received any funding.

All authors have declared no conflicts of interest.