Clinical Performance of the Consensus Immunoscore in Colon Cancer in the Asian Population from the Multicenter International SITC Study

Simple Summary Research interest in Immuno-oncology and the role of the adaptative immune system in the progression and prognosis of colon cancer (CC) is growing. In this study, we evaluated the prognostic value of the consensus Immunoscore in 423 patients with AJCC/UICC-TNM stages I-III CC from Asian care centers. Immunoscore (IS) is a bench-to-digital pathology assay that quantifies CD3+ and cytotoxic CD8+ T-lymphocyte densities within the tumor and its invasive margin, stratifying patients into three categories: Low IS, Intermediate IS, and High IS. Multivariable Cox models stratified by center were used to assess the associations between Immunoscore and outcomes, adjusting for potential confounders, including gender, T-stage, N-stage, sidedness, and MSI. A comparison of the performance of risk prediction models was performed using the likelihood ratio test p-value. In uni/multivariable analyses, a High Immunoscore was significantly associated with prolonged survival of CC patients within the Asian population. BACKGROUND: In this study, we evaluated the prognostic value of Immunoscore in patients with stage I-III colon cancer (CC) in the Asian population. These patients were originally included in an international study led by the Society for Immunotherapy of Cancer (SITC) on 2681 patients with AJCC/UICC-TNM stages I-III CC. METHODS: CD3+ and cytotoxic CD8+ T-lymphocyte densities were quantified in the tumor and invasive margin by digital pathology. The association of Immunoscore with prognosis was evaluated for time to recurrence (TTR), disease-free survival (DFS), and overall survival (OS). RESULTS: Immunoscore stratified Asian patients (n = 423) into different risk categories and was not impacted by age. Recurrence-free rates at 3 years were 78.5%, 85.2%, and 98.3% for a Low, Intermediate, and High Immunoscore, respectively (HR[Low-vs-High] = 7.26 (95% CI 1.75-30.19); p = 0.0064). A High Immunoscore showed a significant association with prolonged TTR, OS, and DFS (p < 0.05). In Cox multivariable analysis stratified by center, Immunoscore association with TTR was independent (HR[Low-vs-Int+High] = 2.22 (95% CI 1.10-4.55) p = 0.0269) of the patient's gender, T-stage, N-stage, sidedness, and MSI status. A significant association of a High Immunoscore with prolonged TTR was also found among MSS (HR[Low-vs-Int+High] = 4.58 (95% CI 2.27-9.23); p <= 0.0001), stage II (HR[Low-vs-Int+High] = 2.72 (95% CI 1.35-5.51); p = 0.0052), low-risk stage-II (HR[Low-vs-Int+High] = 2.62 (95% CI 1.21-5.68); p = 0.0146), and high-risk stage II patients (HR[Low-vs-Int+High] = 3.11 (95% CI 1.39-6.91); p = 0.0055). CONCLUSION: A High Immunoscore is significantly associated with the prolonged survival of CC patients within the Asian population.