title: Magnetic sentinel lymph node biopsy and localization properties of a magnetic tracer in an in vivo porcine model.
abstract: The standard for the treatment of early non-palpable breast cancers is wide local excision directed by wire-guided localization and sentinel lymph node biopsy (SLNB). This has drawbacks technically and due to reliance upon radioisotopes. We evaluated the use of a magnetic tracer for its localization capabilities and concurrent performance of SLNB using a handheld magnetometer in a porcine model as a novel alternative to the current standard. Ethical approval by the IRCAD Ethics Review Board, Strasbourg (France) was received. A magnetic tracer was injected in varying volumes (0.1-5 mL) subcutaneously into the areolar of the left and right 3rd inguinal mammary glands in 16 mini-pigs. After 4 h magnetometer counts were taken at the injection sites and in the groins. The magnetometer was used to localize any in vivo signal from the draining inguinal lymph nodes. Magnetic SLNB followed by excision of the injection site was performed. The iron content of sentinel lymph nodes (SLNs) were graded and quantified. All excised specimens were weighed and volumes were calculated. Univariate analyses were performed to evaluate correlation. Magnetic SLNB was successful in all mini-pigs. There was a significant correlation (r = 0.86; p < 0.01) between magnetometer counts and iron content of SLNs. Grading of SLNs on both H&E and Perl's staining correlated significantly with the iron content (p = 0.001; p = 0.003) and magnetometer counts (p < 0.001; p = 0.004). The peak counts corresponded to the original magnetic tracer injection sites 4 h after injection in all cases. The mean volume and weight of excised injection site specimens was 2.9 cm(3) (SD 0.81) and 3.1 g (SD 0.85), respectively. Injection of ≥0.5 mL magnetic tracer was associated with significantly greater volume (p = 0.05) and weight of excision specimens (p = 0.01). SLNB and localization can be performed in vivo using a magnetic tracer. This could provide a viable alternative for lesion localization and concurrent SLNB in the treatment of non-palpable breast cancer.
authors: Breast Surgery, Department of Research Oncology, King's College London, 3rd Floor Bermondsey Wing, Guy's Hospital Campus, Great Maze Pond, London, SE1 9RT, UK.
authors: Bauke
authors: B
authors: Anninga
authors: Muneer
authors: M
authors: Ahmed
authors: Mieke
authors: M
authors: Van Hemelrijck
authors: Joost
authors: J
authors: Pouw
authors: David
authors: D
authors: Westbroek
authors: Sarah
authors: S
authors: Pinder
authors: Bennie
authors: B
authors: Ten Haken
authors: Quentin
authors: Q
authors: Pankhurst
authors: Michael
authors: M
authors: Douek
mesh_terms: D000818:Animals; D003287:Contrast Media / Q000008:administration & dosage; D004353:Drug Evaluation, Preclinical; D005260:Female; D005290:Ferric Compounds / Q000008:administration & dosage; D006119:Groin; D007267:Injections; D008198:Lymph Nodes / Q000033:anatomy & histology / Q000737:chemistry*; D008280:Magnetics / Q000295:instrumentation; D008321:Mammary Glands, Animal / Q000033:anatomy & histology*; D053758:Nanoparticles / Q000008:administration & dosage; D012394:Rosaniline Dyes; D021701:Sentinel Lymph Node Biopsy / Q000295:instrumentation / Q000379:methods*; D013552:Swine; D013556:Swine, Miniature; D014018:Tissue Distribution
chemical_list: D003287:Contrast Media; D005290:Ferric Compounds; D012394:Rosaniline Dyes; C000499:ferric oxide; C008769:sulfan blue