Local recurrence of breast cancer after MammoSite brachytherapy

Women undergoing breast conservation therapy (BCT) for stage 1 breast cancer have adjuvant external beam radiotherapy (EBR). In addition, the use of brachytherapy radiation is being used. We present two local tumor recurrences for review. Our first patient underwent BCT, sentinel lymph node biopsy (SLNBx) and MammoSite brachytherapy for a T1N0M0 infiltrating ductal carcinoma (IDC) of the right breast. Pathology: 0.6 cm poorly differentiated ER, PR, and Her-2/ Neu negative IDC. At 18 months, she had palpable axillary lymph nodes. Fine needle aspiration and ultrasound-guided core biopsy of a nodule showed IDC. She underwent modified radical mastectomy (MRM) and EBR. Our second patient underwent BCT, SLNBx, and MammoSite brachytherapy for a T1N0M0 IDC of the left breast. Pathology: 0.8 cm poorly differentiated, ER+, PR-, and Her-2/Neu negative tumor. At 18 months, a retroareolar mass was detected. Ultrasound guided core needle biopsy showed recurrent IDC. She chose a re-excision and EBR and not MRM. Pathology: 1.3 cm poorly differentiated, ER+, PR-, and Her-2/Neu negative tumor. Our 2 recurrences were >2 cm away from the lumpectomy site and therefor outside the 1 cm treatment plan of the MammoSite catheter. Both recurrences were biologically identical to the initial tumors and are felt to be local failures rather than new primaries.