title: Predictive Ability of18F-fluorodeoxyglucose Positron Emission Tomography/computed Tomography for Pathological Complete Response and Prognosis after Neoadjuvant Chemotherapy in Triple-negative Breast Cancer Patients.
abstract: OBJECTIVE
  The mortality of patients with locally advanced triple-negative breast cancer (TNBC) is high, and pathological complete response (pCR) to neoadjuvant chemotherapy (NAC) is associated with improved prognosis. This retrospective study was designed and powered to investigate the ability of18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) to predict pathological response to NAC and prognosis after NAC.
  
  
  METHODS
  The data of 32 consecutive women with clinical stage II or III TNBC from January 2006 to December 2013 in our institution who underwent FDG-PET/CT at baseline and after NAC were retrospectively analyzed. The maximum standardized uptake value (SUVmax) in the primary tumor at each examination and the change in SUVmax(ΔSUVmax) between the two scans were measured. Correlations between PET parameters and pathological response, and correlations between PET parameters and disease-free survival (DFS) were examined.
  
  
  RESULTS
  At the completion of NAC, surgery showed pCR in 7 patients, while 25 had residual tumor, so-called non-pCR. Median follow-up was 39.0 months. Of the non-pCR patients, 9 relapsed at 3 years. Of all assessed clinical, biological, and PET parameters, N-stage, clinical stage, and ΔSUVmaxwere predictors of pathological response (pvalue of 0.0288, 0.0068, 0.0068 respectively; Fischer's exact test). The cut-off value of ΔSUVmaxto differentiate pCR evaluated by the receiver operating characteristic (ROC) curve analysis was 81.3%. Three-year disease-free survival (DFS) was lower in patients with non-pCR than in patients with pCR (p=0.328, log-rank test). The cut-off value of ΔSUVmaxto differentiate 3-year DFS evaluated by the ROC analysis was 15.9%. In all cases, 3-year DFS was lower in patients with ΔSUVmax<15.9% than in patients with ΔSUVmax≥15.9% (P=0.0078, log-rank test). In non-pCR patients, 3-year DFS was lower in patients with ΔSUVmax<15.9% than in patients with ΔSUVmax≥15.9% (P=0.0238, log-rank test).
  
  
  CONCLUSIONS
  FDG-PET/CT at baseline and after NAC could predict pathological response to NAC before surgery and the clinical outcome after surgery in locally advanced TNBC patients.
authors.affiliation: Department of Breast Oncology, National Hospital Organization Shikoku Cancer Center, Matsuyama, Japan.
authors.forename: Sachiko
authors.initials: S
authors.lastname: Kiyoto
authors.affiliation: Department of Diagnostic Radiology, National Hospital Organization Shikoku Cancer Center, Matsuyama, Japan.
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Sugawara
authors.affiliation: Department of Diagnostic Radiology, National Hospital Organization Shikoku Cancer Center, Matsuyama, Japan.
authors.forename: Kohei
authors.initials: K
authors.lastname: Hosokawa
authors.affiliation: Department of Clinical Laboratory, National Hospital Organization Shikoku Cancer Center, Matsuyama, Japan.
authors.forename: Rieko
authors.initials: R
authors.lastname: Nishimura
authors.affiliation: Section of Cancer Prevention and Epidemiology, Clinical Research Center, National Hospital Organization Shikoku Cancer Center, Matsuyama, Japan.
authors.forename: Natsumi
authors.initials: N
authors.lastname: Yamashita
authors.affiliation: Department of Breast Oncology, National Hospital Organization Shikoku Cancer Center, Matsuyama, Japan.
authors.forename: Shozo
authors.initials: S
authors.lastname: Ohsumi
authors.affiliation: Department of Radiology, Ehime University, Matsuyama, Japan.
authors.forename: Teruhito
authors.initials: T
authors.lastname: Mochizuki
keywords: FDG-PET/CT; Metabolic Response; Neoadjuvant Chemotherapy; Prognosis; Triple negative breast cancer