[A Case of Recurrent Breast Cancer Treated with Local Irradiation Using Leadless Pacemaker Implantation].

A 68-year-old woman noticed a tumor in her left breast and visited our hospital. She was diagnosed with left breast cancer cT2N2M0, stage ⅢA, and surgery was performed after the neoadjuvant chemotherapy. Although this case was indicated for radiation therapy(PMRT)after total mastectomy, postoperative radiation was not performed due to an implantable pacemaker placed in the left anterior chest. Therefore, postoperative adjuvant therapy with endocrine therapy was started. After 3 years of treatment, her left axillary lymph node was enlarged, and needle biopsy confirmed metastasis and recurrence. When local excision was performed, postoperative irradiation was deemed necessary because residual microlesions were suspected. Irradiation planning did not deny the possibility that the pacemaker in the anterior chest indwelling could become the irradia- tion range. Therefore, a leadless pacemaker was inserted, and local irradiation(50 Gy/20 Fr)was performed without complications. The next treatment is fulvestrant, and no recurrence has been observed 6months postoperatively.