A randomized controlled trial of metastasis-directed therapy for oligometastases in breast cancer: OLIGAMI trial (JCOG2110).

Oligometastasis is a concept that refers to the condition between localized cancer and widespread distant metastases; however, a consensus on the definition has yet to be reached. Metastasis-directed therapy (MDT) has recently been established to incorporate local therapy, such as radiotherapy and surgery, for distant metastases. Previous trials have proposed the possibility of long-term survival with the administration of MDT for patients with oligometastases. However, the efficacy and safety of MDT have not been sufficiently validated. We are conducting this clinical trial to confirm the superiority of MDT combined with subtype-specific systemic drug therapy over systemic drug therapy alone in patients with oligometastatic breast cancer. Here, "oligometastases" are defined as tumors with a maximum diameter ≤ 3 cm and total number ≤ 3. The primary endpoint is overall survival. We intend to enroll 340 patients from 62 institutions over a 3-year period. This trial has been registered in the Japan Registry of Clinical Trials (jRCTs031230439).