Iodine grain isotope detection compared to standard metal guide detection for breast cancers: The IODINE BREAST, a randomised, non-inferiority trial.

[INTRODUCTION] Preoperative localization of non palpable breast lesions is crucial. Guide wire localization (GWL) is the gold standard technique. However, it is very painful, protrudes from the breast, thus limiting the patient's movements and generating discomfort. Radioguided seed localization consists of placing a radioactive I within the tumour. It offers greater comfort with lesser pain.

[MATERIALS AND METHODS] The IODINE BREAST is a randomized, non-inferiority trial. Patient were eligible if they were 18 years old with a non-palpable carcinoma requiring conservative surgical management. Patients were randomised for the preoperative localization technique. The primary objective is to compare the quality of surgical excision. Secondary objectives include re-operation rates, localization time, surgery duration, complications, and patients' satisfaction.

[RESULTS] A total number of 378 patients were included in the study; 184 were randomized in 99mTc guided arm and 186 in I-seed arm. Demographical characteristics were similar between both arms. The primary endpoint analysis showed non-inferiority between the 125I-seed and GWL methods for incomplete resection rates. Surgical outcomes, including re-operation rates and specimen volumes, were comparable. Time between device insertion and surgery differed significantly between the two groups, with the 125I-seed having a longer time-to-surgery. Patient's satisfaction was similar, though the 125I-seed arm reported less pain and discomfort.

[CONCLUSION] 125I-seed localization is shown to be non-inferior to guide-wire localization. It offers less pain, patient comfort and the possibility of its placement many days before surgery. 125I-seed redefines standards in breast surgery, by combining precision, convenience, and patient-centered care. The trial is registered with ClinicalTrials.gov under the number NCT02759133.