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.