Kovacs A, et al. - In this large randomized trial, investigators assessed how tumor-infiltrating lymphocytes (TILs) impact the postoperative radiotherapy (RT) effect on ipsilateral breast tumor recurrence (IBTR) among 1,178 subjects with stage I and II breast cancer. They observed TILs of less than 10% in 71% of patients. They noted RT, high TILs, grade, and age (≥ 50 vs < 50 years) were predictive of IBTR when RT, TILs, subtype, age, and grade were independent variables in the multivariable regression analysis with IBTR as dependent variable. In the low TILs group (not in the high TILs group), they found RT was significantly advantageous. They suggested that the risk for an IBTR was independently reduced by high values of TILs in the primary tumor. They also reported a larger benefit from RT (regarding the risk of IBTR) in subjects with breast cancer with low TILs.