【Abstract】 Objective To explore the value of T lymphocyte subsets in rectal cancer treated with short-course preoperative radiotherapy.Methods 102 patients with rectal cancer underwent surgery（n=52） or preoperative radiotherapy（n=50）.Blood samples were taken before radiotherapy,operation,and on day 14 after surgery.T lymphocyte subsets in peripheral blood were detected by flow cytometry,and controlled with 40 health volunteers.Results CD₃⁺,CD₄⁺cells and the rate of CD₄⁺/CD₈⁺ were decreased and CD₈⁺ cells were increased in radiotherapy patients compared to control group（P<0.05）;The T lymphocyte subsets in preoperative radiotherapy group were not different between preoperation and postoperation The recovery of T lymphocyte subsets were not significantly different in two groups（P>0.05）.Conclusion Short course of preoperative radiotherapy does not affect immune function in rectal cancer patients.更多还原