Metastasis-directed Therapy for Oligometastases of Breast Cancer

OLIGAMI trial is a multi-institutional, two-arm, open-label, randomized controlled phase III trial being conducted with the participation of 50 hospitals belonging to Japan Clinical Oncology Group. After the first registration, all patients will be performed in a 12-week, subtype-specific, systemic therapy consisting of CDK4/6 inhibitors with hormonal therapy for luminal BC, docetaxel with trastuzumab and pertuzumab for HER2-positive BC, chemotherapy with immune checkpoint inhibitors for triple-negativeBC expressing PD-L1, and olaparib for cases harboring BRCA mutations. For other triple-negative BC, chemotherapy will be administered. If this 12-week systemic therapy does not cause any progression or complete response, patients proceed to second registration for randomization; arm A continues same systemic therapy alone, and arm B performs MDT followed by same systemic therapy. The MDT will involve either RT or surgery, and RT will involve mainly SBRT and partly conventional RT.