title: Repeated inductive heating using a sintered MgFe2O4 needle for minimally invasive local control in breast cancer therapy.
abstract: OBJECTIVE
  This study investigated the efficacy of repeated thermotherapy for breast cancer utilising a novel sintered MgFe(2)O(4) needle and alternating current (AC) magnetic field in xenograft animal models mimicking human breast cancer.
  
  
  METHODS
  A sintered MgFe(2)O(4) needle and an apparatus to apply an AC magnetic field were prepared for this study. Animals bearing BT-474 tumours (mean (+/-standard deviation) volume, 471 +/- 153 mm(3)) were divided into four groups. A sintered MgFe(2)O(4) needle (length, 5 mm) was placed in the centre of each tumour. An AC magnetic field (amplitude, 4 kA/m; 2 kW; 540 kHz) was applied for 10 min once, twice or three times for the first, second and third groups, respectively, and was not applied for the control group. Temperature during treatment and tumour volume 8 weeks after first treatment were assessed.
  
  
  RESULTS
  Maximum tumour temperature tended to increase in repeated-application groups: group 1, 59.2 +/- 4 degrees C; group 2, 58.9 +/- 3.3 degrees C and 61.2 +/- 8.9 degrees C for the first and second applications; and group 3, 60.4 +/- 4.6 degrees C, 62.1 +/- 7.8 degrees C and 71.1 +/- 6.1 degrees C for the first, second and third applications. Tumour volumes in control, groups 1, 2 and 3 at 8 weeks after treatment were 3633 +/- 2478 mm(3), 3240 +/- 1031 mm(3), 1252 +/- 1289 mm(3) and 0 mm(3), respectively. Tumours were significantly smaller in group 3 than in the control and group 1 at 8 weeks.
  
  
  CONCLUSIONS
  The efficacy of repeated inductive heating utilising a sintered MgFe(2)O(4) needle was demonstrated. Thermotherapy using the present method may offer an effective non-surgical treatment for human breast cancer.
authors.affiliation: Department of Organ Regenerative Surgery, Ehime University, Ehime, Japan. onsen@m.ehime-u.ac.jp
authors.forename: Shungo
authors.initials: S
authors.lastname: Yukumi
authors.forename: Yuji
authors.initials: Y
authors.lastname: Watanabe
authors.forename: Atsushi
authors.initials: A
authors.lastname: Horiuchi
authors.forename: Takashi
authors.initials: T
authors.lastname: Doi
authors.forename: Kohichi
authors.initials: K
authors.lastname: Sato
authors.forename: Motohira
authors.initials: M
authors.lastname: Yoshida
authors.forename: Yuji
authors.initials: Y
authors.lastname: Yamamoto
authors.forename: Tsunehiro
authors.initials: T
authors.lastname: Maehara
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Aono
authors.forename: Takashi
authors.initials: T
authors.lastname: Naohara
authors.forename: Kanji
authors.initials: K
authors.lastname: Kawachi
mesh_terms: D000818:Animals; D001943:Breast Neoplasms / Q000628:therapy*; D005260:Female; D005290:Ferric Compounds; D006801:Humans; D006979:Hyperthermia, Induced / Q000295:instrumentation*; D055909:Magnetic Field Therapy / Q000379:methods*; D051379:Mice; D023421:Models, Animal; D009339:Needles; D009368:Neoplasm Transplantation; D010087:Oxides; D012881:Skin Temperature
chemical_list: D005290:Ferric Compounds; D010087:Oxides