T categories for breast cancer Higher T numbers mean a larger tumor and/or wider spread to tissues near the breast. T1 (includes T1a, T1b, and T1c): Tumor is 2 cm (3/4 of an inch) or less across. T2: Tumor is more than 2 cm but not more than 5 cm (2 inches) across. T3: Tumor is more than 5 cm across.
