The immune reaction at tumour site determines cancer evolution and clinical outcome in patients with colorectal cancer, regardless of the local extent and spread of the tumour, according to the findings of Jérôme Galon, INSERM Research Director, Paris, and co-workers. The analysis of immunological parameters should therefore be integrated into the process of staging and clinical decision finding, says Galon at the 2nd European Congress of Immunology ECI 2009.
Colorectal cancer is one of the most common malignancies, with an estimated annual incidence of one million cases worldwide. The prognosis is severe, with a 5-year-survival of 55 %. Surgical resection is effective for localized disease. An additional post-surgical course of chemotherapy is reserved for patients with lymph node or distant metastases. But also a significant proportion of patients with local disease (Stage I/II patients) develops recurrence and dies from the disease. "There is clearly a need to identify novel predictive factors to identify patients with the potential for colon cancer progression", Galon stresses.
Actually, assessing patient survival and choosing the optimal therapy are based on the currently used classification. Staging includes tumour size, local spread and distant metastases. Galon und co-workers showed that a detailed analysis of local immune reaction would be a better predictor, especially in identifying high risk patients with minimal invasive tumours.
Galon analysed the infiltration of lymphocytes, the most important cells of immune response, into the tumour and peritumoural tissue in 415 patients with colorectal cancer. The scientist developed a comprehensive analysis of the nature, the functional orientation, the density and the organization of the immune cell populations within the tumour. He performed a large-scale analysis of in situ immune parameters as well as an original analysis of gene expression, which enables the identification of genes whose co-expression is correlated with cancer evolution. These data were confirmed in a blinded manner in two independent patient cohorts>