title: ¹⁸F-FLT PET/CT as an imaging tool for early prediction of pathological response in patients with locally advanced breast cancer treated with neoadjuvant chemotherapy: a pilot study.
abstract: OBJECTIVE
  We evaluated whether (18)F-3'-deoxy-3'-fluorothymidine positron emission tomography (FLT PET) can predict the final postoperative histopathological response in primary breast cancer after the first cycle of neoadjuvant chemotherapy (NCT).
  
  
  METHODS
  In this prospective cohort study of 15 patients with locally advanced operable breast cancer, FLT PET evaluations were performed before NCT, after the first cycle of NCT, and at the end of NCT. All patients subsequently underwent surgery. Variables from FLT PET examinations were correlated with postoperative histopathological results.
  
  
  RESULTS
  At baseline, median of maximum standardized uptake values (SUVmax) in the groups showing a complete pathological response (pCR) + residual cancer burden (RCB) I, RCB II or RCB III did not differ significantly for the primary tumour (5.0 vs. 2.9 vs. 8.9, p = 0.293) or for axillary nodes (7.9 vs. 1.6 vs. 7.0, p = 0.363), whereas the Spearman correlation between SUVmax and Ki67 proliferation rate index was significant (r = 0.69, p < 0.001). Analysis of the relative percentage change of SUVmaxin the primary tumour (∆SUVTmax(t₁)) and axillary nodes (∆SUVNmax(t₁)) after the first NCT cycle showed that the power of ∆SUVTmax(t 1) to predict pCR + RCB I responses (AUC = 0.91, p < 0.001) was statistically significant, whereas ∆SUVNmax(t₁) had a moderate ability (AUC = 0.77, p = 0.119) to separate subjects with ΔSUVTmax(t₁) > -52.9 % into two groups: RCB III patients and a heterogeneous group that included RCB I and RCB II patients. A predictive score μ based on ΔSUVTmax(t₁) and ΔSUVNmax(t₁) parameters is proposed.
  
  
  CONCLUSIONS
  The preliminary findings of the present study suggest the potential utility of FLT PET scans for early monitoring of response to NCT and to formulate a therapeutic strategy consistent with the estimated efficacy of NCT. However, these results in a small patient population need to be validated in a larger independent cohort.
authors: Nuclear Medicine Unit, Fondazione IRCCS Istituto Nazionale dei Tumori - Milan (Italy), 20133, Milan, Italy.
authors: Flavio
authors: F
authors: Crippa
authors: Roberto
authors: R
authors: Agresti
authors: Marco
authors: M
authors: Sandri
authors: Gabriella
authors: G
authors: Mariani
authors: Barbara
authors: B
authors: Padovano
authors: Alessandra
authors: A
authors: Alessi
authors: Giulia
authors: G
authors: Bianchi
authors: Emilio
authors: E
authors: Bombardieri
authors: Ilaria
authors: I
authors: Maugeri
authors: Mario
authors: M
authors: Rampa
authors: Maria Luisa
authors: ML
authors: Carcangiu
authors: Giovanna
authors: G
authors: Trecate
authors: Claudio
authors: C
authors: Pascali
authors: Anna
authors: A
authors: Bogni
authors: Gabriele
authors: G
authors: Martelli
authors: Filippo
authors: F
authors: de Braud
mesh_terms: D000328:Adult; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy; D017024:Chemotherapy, Adjuvant; D015224:Dideoxynucleosides; D005260:Female; D006801:Humans; D008875:Middle Aged; D064847:Multimodal Imaging; D010865:Pilot Projects; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D014057:Tomography, X-Ray Computed
chemical_list: D015224:Dideoxynucleosides; D019275:Radiopharmaceuticals; C002854:alovudine