Kovács A, et al. - In a large randomized trial (Swedish Breast Cancer Group 91 Radiotherapy-SweBCT91RT) enrolling 1,178 patients with breast cancer stage I and II, researchers investigated how the impact of postoperative radiotherapy (RT) on ipsilateral breast tumor recurrence (IBTR) was influenced by tumor infiltrating lymphocytes (TILs). In a random manner, patients were assigned to breast-conserving surgery plus postoperative RT or breast-conserving surgery only. A median follow up of 15.2 years was performed. The risk for an IBTR was seemed to be independently lowered by high values of TILs in the primary tumor. With regard to risk of IBTR, patients with low TILs may get a greater benefit from RT.