title: Does the pretreatment tumor sampling location correspond with metabolic activity on 18F-FDG PET/CT in breast cancer patients scheduled for neoadjuvant chemotherapy?
abstract: OBJECTIVE
  To define the correlation between the core biopsy location and the area with highest metabolic activity on 18F-FDG PET/CT in stage II-III breast cancer patients before neoadjuvant chemotherapy. Also, we would like to select a subgroup of patients in which PET/CT information may optimize tumor sampling.
  
  
  METHODS
  A PET/CT in prone position was acquired in 199 patients with 203 tumors. The distance and relative difference in standardized uptake value (SUV) between core biopsy localization (indicated by a marker) and area with highest degree of FDG uptake were evaluated. A distance ≥ 2 cm and a relative difference in SUV ≥ 25% were considered clinically relevant and a combination of both was defined as non-correspondence. Non-correspondence for different tumor characteristics (TNM stage, lesion morphology on MRI and PET/CT, histology, subtype, grade, and Ki-67) was assessed.
  
  
  RESULTS
  Non-correspondence was found in 28 (14%) of 203 tumors. Non-correspondence was significantly associated with T-stage, lesion morphology on MRI and PET/CT, tumor diameter, and histologic type. It was more often seen in tumors with a higher T-stage (p = 0.028), diffuse (non-mass) and multifocal tumors on MRI (p = 0.001), diffuse and multifocal tumors on PET/CT (p<0.001), tumors >3 cm (p<0.001), and lobular carcinomas (p<0.001). No association was found with other features.
  
  
  CONCLUSIONS
  Non-correspondence between the core biopsy location and area with highest FDG uptake is regularly seen in stage II-III breast cancer patients. PET/CT information and possibly FDG-guided biopsies are most likely to improve pretreatment tumor sampling in tumors >3 cm, lobular carcinomas, and diffuse and multifocal tumors.
authors.affiliation: Department of Nuclear Medicine, Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands; Department of Surgical Oncology, Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands. Electronic address: b.koolen@nki.nl.
authors.forename: Bas B
authors.initials: BB
authors.lastname: Koolen
authors.forename: Lotte E
authors.initials: LE
authors.lastname: Elshof
authors.forename: Claudette E
authors.initials: CE
authors.lastname: Loo
authors.forename: Jelle
authors.initials: J
authors.lastname: Wesseling
authors.forename: Marie-Jeanne T F D
authors.initials: MJ
authors.lastname: Vrancken Peeters
authors.forename: Wouter V
authors.initials: WV
authors.lastname: Vogel
authors.forename: Emiel J Th
authors.initials: EJ
authors.lastname: Rutgers
authors.forename: Renato A
authors.initials: RA
authors.lastname: Valdés Olmos
mesh_terms: D000328:Adult; D000368:Aged; D062005:Biopsy, Large-Core Needle; D001943:Breast Neoplasms / Q000175:diagnosis / Q000188:drug therapy* / Q000378:metabolism*; D017024:Chemotherapy, Adjuvant / Q000706:statistics & numerical data*; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics; D006801:Humans; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D064847:Multimodal Imaging / Q000706:statistics & numerical data; D020360:Neoadjuvant Therapy / Q000706:statistics & numerical data; D009426:Netherlands; D049268:Positron-Emission Tomography / Q000706:statistics & numerical data*; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D018401:Sample Size; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000706:statistics & numerical data*; D016896:Treatment Outcome
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: 18F-FDG PET/CT; Breast cancer; Core biopsy; Heterogeneity; Neoadjuvant chemotherapy; Tumor localization