Identification of residual breast tumour localization after neo-adjuvant chemotherapy using a radioactive 125 Iodine seed.

INTRODUCTION: The use of neo-adjuvant chemotherapy has increased in the treatment of loco-regionally advanced primarily operable breast cancer. As a result of improved neo-adjuvant chemotherapy regimes the number of clinical as well as radiological responses have increased. In case of a complete response it is difficult to identify residual disease and to perform an adequate radical breast-conserving surgery. Therefore localization of the original tumour bed is mandatory. In this study we propose a novel technique with a seed containing radioactive 125 Iodine ((125)I). The (125)I has a half-time of 60 days and is therefore still recognisable with a gamma probe after admittance of several courses of neo-adjuvant chemotherapy.

MATERIAL AND METHODS: In the period from July 2003 and November 2008, 47 consecutive patients had successful (125)I seed localization of a breast tumour before starting neo-adjuvant chemotherapy.

RESULTS: The overall clinical response rate to neo-adjuvant chemotherapy was 100%. Complete clinical response occurred in 34 patients, partial clinical response occurred in 13 patients. Complete radiological response occurred in 18 patients, partial radiological response occurred in 29 patients. The initial surgical treatment consisted of breast-conserving surgery for all 47 patients, after a mean of 170 days (range: 70-220) after (125)I seed localization. In 19 patients pathology revealed no residual tumour, 23 patients showed a partial response. Only 3 lumpectomies were irradical.

CONCLUSION: This study has shown that (125)I seed localization is a novel and highly successful technique in localizing the tumour bed in patients who receive neo-adjuvant chemotherapy for breast cancer leading to a high percentage of radical margins in case of breast-conserving surgery.