title: Histopathology of breast cancer after magnetic resonance-guided high-intensity focused ultrasound and radiofrequency ablation.
abstract: OBJECTIVE
  Magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) ablation and radiofrequency ablation (RFA) are being researched as possible substitutes for surgery in breast cancer patients. The histopathological appearance of ablated tissue has not been studied in great detail. This study aimed to compare histopathological features of breast cancer after MR-HIFU ablation and RFA.
  
  
  RESULTS
  MR-HIFU ablation and RFA were performed in- and ex-vivo. Tumours in six mastectomy specimens were partially ablated with RFA or MR-HIFU. In-vivo MR-HIFU ablation was performed 3-6 days before excision; RFA was performed in the operation room. Tissue was fixed in formalin and processed to haematoxylin and eosin (H&E) and cytokeratin-8 (CK-8)-stained slides. Morphology and cell viability were assessed. Ex-vivo ablation resulted in clear morphological changes after RFA versus subtle differences after MR-HIFU. CK-8 staining was decreased or absent. H&E tended to underestimate the size of thermal damage. In-vivo MR-HIFU resulted in necrotic-like changes. Surprisingly, some ablated lesions were CK-8-positive. Histopathology after in-vivo RFA resembled ex-vivo RFA, with hyper-eosinophilic stroma and elongated nuclei. Lesion borders were sharp after MR-HIFU and indistinct after RFA.
  
  
  CONCLUSIONS
  Histopathological differences between MR-HIFU-ablated tissue and RF-ablated tissue were demonstrated. CK-8 was more reliable for cell viability assessment than H&E when used directly after ablation, while H&E was more reliable in ablated tissue left in situ for a few days. Our results contribute to improved understanding of histopathological features in breast cancer lesions treated with minimally invasive ablative techniques.
authors.affiliation: Department of Radiology, University Medical Center Utrecht, Utrecht, the Netherlands.
authors.forename: Floortje M
authors.initials: FM
authors.lastname: Knuttel
authors.affiliation: Department of Surgery, University Medical Center Utrecht, Utrecht, the Netherlands.
authors.forename: Laurien
authors.initials: L
authors.lastname: Waaijer
authors.affiliation: Department of Radiotherapy, University Medical Center Utrecht, Utrecht, the Netherlands.
authors.forename: Laura G
authors.initials: LG
authors.lastname: Merckel
authors.affiliation: Department of Radiology, University Medical Center Utrecht, Utrecht, the Netherlands.
authors.forename: Maurice A A J
authors.initials: MA
authors.lastname: van den Bosch
authors.affiliation: Department of Surgery, University Medical Center Utrecht, Utrecht, the Netherlands.
authors.forename: Arjen J
authors.initials: AJ
authors.lastname: Witkamp
authors.affiliation: Image Sciences Institute, University Medical Center Utrecht, Utrecht, the Netherlands.
authors.forename: Roel
authors.initials: R
authors.lastname: Deckers
authors.affiliation: Department of Pathology, University Medical Center Utrecht, Utrecht, the Netherlands.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: van Diest
mesh_terms: D055011:Ablation Techniques; D001940:Breast / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D001943:Breast Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D005260:Female; D057086:High-Intensity Focused Ultrasound Ablation; D006801:Humans; D053533:Keratin-8 / Q000378:metabolism*; D008279:Magnetic Resonance Imaging; D008408:Mastectomy; D025321:Surgery, Computer-Assisted
chemical_list: D053533:Keratin-8
keywords: MR-HIFU; RFA; ablation; breast cancer; histopathology; magnetic resonance-guided high-intensity focused ultrasound ablation; minimally invasive; radiofrequency ablation