title: FDG PET/CT during neoadjuvant chemotherapy may predict response in ER-positive/HER2-negative and triple negative, but not in HER2-positive breast cancer.
abstract: BACKGROUND
  Response monitoring with MRI during neoadjuvant chemotherapy (NAC) in breast cancer is promising, but knowledge of breast cancer subtype is essential. The aim of the present study was to evaluate the relevance of breast cancer subtypes for monitoring of therapy response during NAC with 18F-FDG PET/CT.
  
  
  METHODS
  Evaluation included 98 women with stages II and III breast cancer. PET/CTs were performed before and after six or eight weeks of NAC. FDG uptake was quantified using maximum standardized uptake values (SUVmax). Tumors were divided into three subtypes: HER2-positive, ER-positive/HER2-negative, and triple negative. Tumor response at surgery was assessed dichotomously (presence or absence of residual disease) and ordinally (breast response index, representing relative change in tumor stage). Multivariate regression and receiver operating characteristic (ROC) analyses were employed to determine associations with pathological response.
  
  
  RESULTS
  A (near) complete pathological response was seen in 19 (76%) of 25 HER2-positive, 7 (16%) of 45 ER-positive/HER2-negative, and 20 (71%) of 28 triple negative tumors. Multivariate regression of pathological response indicated a significant interaction between change in FDG uptake and breast cancer subtype. The area under the ROC curve was 0.35 (0.12-0.64) for HER2-positive, 0.90 (0.76-1.00) for ER-positive/HER2-negative, and 0.96 (0.86-1.00) for triple negative tumors. We found no association between age, stage, histology, or baseline SUVmax and pathological response.
  
  
  CONCLUSIONS
  Response monitoring with PET/CT during NAC in breast cancer seems feasible, but is dependent on the breast cancer subtype. PET/CT may predict response in ER-positive/HER2-negative and triple negative tumors, but seems less accurate in HER2-positive tumors.
authors: 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.
authors: Bas B
authors: BB
authors: Koolen
authors: Kenneth E
authors: KE
authors: Pengel
authors: Jelle
authors: J
authors: Wesseling
authors: Wouter V
authors: WV
authors: Vogel
authors: Marie-Jeanne T F D
authors: MJ
authors: Vrancken Peeters
authors: Andrew D
authors: AD
authors: Vincent
authors: Kenneth G A
authors: KG
authors: Gilhuijs
authors: Sjoerd
authors: S
authors: Rodenhuis
authors: Emiel J Th
authors: EJ
authors: Rutgers
authors: Renato A
authors: RA
authors: Valdés Olmos
mesh_terms: D000328:Adult; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D019540:Area Under Curve; D002277:Carcinoma / Q000737:chemistry / Q000175:diagnosis* / Q000188:drug therapy*; D017024:Chemotherapy, Adjuvant; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008875:Middle Aged; D064847:Multimodal Imaging; D020360:Neoadjuvant Therapy; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D012372:ROC Curve; D019275:Radiopharmaceuticals; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis; D011960:Receptors, Estrogen / Q000032:analysis; D014057:Tomography, X-Ray Computed; D064726:Triple Negative Breast Neoplasms / Q000175:diagnosis* / Q000188:drug therapy*
chemical_list: D019788:Fluorodeoxyglucose F18; D019275:Radiopharmaceuticals; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; C508053:ERBB2 protein, human
keywords: Breast cancer; Neoadjuvant chemotherapy; PET/CT; Response monitoring; Subtype