Prognostic Significance of Tumor-Infiltrating Lymphocytes for Patients With Colorectal Cancer

OBJECTIVE: To evaluate the prognostic significance of tumor-infiltrating lymphocytes (TILs) in patients with colorectal cancer. DESIGN: A retrospective review of prospectively collected data. SETTING: Tertiary care hospital. PATIENTS: A total of 546 patients who underwent curative surgery for primary nonmetastatic colorectal cancers from May 1, 2004, through December 31, 2007. MAIN OUTCOME MEASURES: The prognostic value of macroscopic ulceration, tumor border configuration, and TILs at the invasive margin was assessed. RESULTS: The low TIL group was significantly correlated with a poorly differentiated status and perineural invasion. During the median 54-month follow-up period, the low TIL group had significantly lower 5-year overall survival and disease-free survival rates than the high TIL group of patients with stage III colorectal cancer (P = .005 and P = .03, respectively); however, for patients with stage I and II cancers, the survival rates did not differ between the 2 groups. The 5-year overall survival and 5-year disease-free survival rates were significantly different between the high and low TIL groups of patients with rectal cancer (P = .003 and P = .01, respectively). The multivariate analysis confirmed that the TIL grade was significantly and independently associated with a worse prognosis for overall survival but not for disease-free survival. CONCLUSIONS: An inflammatory cell reaction at the tumor invasive border is considered a useful predictor of survival after colorectal cancer surgery, particularly for patients with stage III disease or rectal cancer.