This document summarizes several presentations from the ASCO conference on breast cancer treatment. It discusses trials on omitting radiation therapy for certain breast cancer patients, using central Ki67 testing to guide treatment, using multi-gene assays to define patients who can safely avoid radiation, and predictive biomarkers for DCIS recurrence and response to radiation versus endocrine therapy. It also reviews a trial on adjuvant chemotherapy plus endocrine therapy versus endocrine therapy alone for older patients with ER-positive breast cancer, and an analysis of residual cancer burden after neoadjuvant immunotherapy and chemotherapy for triple-negative breast cancer.