Radioguided occult lesion localisation in breast cancer using an intraoperative portable gamma camera: first results

Abstract

The role of the radioguided occult lesion localisation (ROLL) technique in breast cancer has been increasing in recent years. One of the important drawbacks of such a technique is radiotracer spillage within the mammary gland that makes the precise lesion resection difficult, and this requires the use of a hook-wire collocation to reach the lesion. The possibility of obtaining an intraoperative image of the specimen could help to confirm whether the lesion is correctly removed. Some types of portable gamma cameras have been designed, but up to now, intraoperative use has been confined to surgery of parathyroid adenomas and sentinel lymph node location. The aim of the study was to value the usefulness of an intraoperative gamma camera to assess the resection of non-palpable breast lesions. The study involved 42 women diagnosed with non-palpable early breast cancer. Lymphoscintigraphy was performed on the day before surgery by injection of (99m)Tc-labelled nanocolloid. During surgery a gamma probe was used to guide the surgeon, and afterwards images of the surgical bed and the tumoral specimen were acquired by means of a portable gamma camera, fitted with a pinhole collimator. A (99m)Tc pointer was used to draw an outline image around the specimen. On lymphoscintigraphy, radiotracer was concentrated in 31 cases. During surgery, all lesions were removed. In the images acquired by the portable gamma camera, the lesion was centred inside the surgical specimen in 23 of 42 cases, non-centred in 15 and in contact in 4 cases. Congruence of 60% was found between the intraoperative images and the histopathological results. The posterior margin was the most frequently involved. The whole acquisition time for the tumoral specimen with its margins was 5 min at most. The use of portable gamma cameras in theatre is in an early phase. The short period of time required during the surgical procedure will allow the surgical team to improve this technique until it can replace hand-held probes. The intraoperative acquisition of such images can predict the involvement of surgical margins, avoiding future surgical procedures.