MaMaLoc: a study on the use of a magnetic marker for tumor localization in breast cancer surgery

INTERVENTION: Subjects will be allocated randomly to either WGL (control group) or MaMaLoc (interventional group) by drawing an envelope. In the interventional treatment group (N=35), localization is performed using magnetic localization: the MaMaLoc technique. With this technique, the radiologist places a magnetic marker in the tumour up to 30 days prior to surgery, using ultrasound guidance. . A two‐way mammography is obtained directly subsequently to confirm correct placement of the marker. For a subset of patients (max N=10) in the interventional group in which a biopsy site marker or other localisation marker (such as o‐ring, twist‐maker) was already in situ, at the day of surgery, patients will be asked to undergo an extra mammography to assess marker migration and ensure continued proper localization of the experimental marker. The other localisation marker is used as reference in both post‐placement and pre‐surgery images. During surgery, a commercially available magnetic detector (Endomag Sentimag) is used to accurately detect the marker, and guide surgery. During measuring at the OR, polymer surgical instruments are used to prevent disrupting the magnetic detector signal (B Braun Aesculaep SUSI instruments). If the technology is insufficient in guiding the surgeon, he or she may opt to fall back to ultrasound guided surgery. In the standard treatment group (N = 35), subjects receive the wire guided localization technique. In wire guided localization, a radiologist places a metal wire with an anchor tip in or near the tumour using ultrasound guidance, prior to surgery (at maximum one day in advance). A two‐way mammography is obtained directly subsequently to confirm correct placement of the wire (tip). During the subsequent surgery, the surgeon follows the wire and resects the tissue around the tip including the wire. CONDITION: Mamma carcinoma, Tumor localization, Patient outcome, Usability, Innovation ; ; PRIMARY OUTCOME: Surgical usability, (defined as the general System Usability Scale (SUS) SECONDARY OUTCOME: • Surgical convenience (questionnaire and RTA) ; ; • Radiologist satisfaction (SUS) ; ; • Patient reported pain (VAS) ; ; • Patient convenience of the technique (Likert scale) ; ; • Clinical parameters ; ; • Success rate of localization procedure ; ; • Resection margin status ; ; • Operation time ; ; • Re‐operation rate ; ; • Specimen weight and volume ; ; • Marker migration (intervention group subset, max N=10) ; ; • Learning curve for the MaMaLoc localization technique. ; INCLUSION CRITERIA: breast cancer patients aged =18 years unifocal tumour good ultrasound visibility scheduled for breast conserving surgery with localization