title: Correlation of Molecular Subtypes of Invasive Ductal Carcinoma of Breast with Glucose Metabolism in FDG PET/CT: Based on the Recommendations of the St. Gallen Consensus Meeting 2013.
abstract: OBJECTIVE
  This study aimed to investigate the relationship between the SUVmax of primary breast cancer lesions and the molecular subtypes based on the recommendations of the St. Gallen consensus meeting 2013.
  
  
  METHODS
  Clinical records of patients who underwent F-18 FDG PET/CT for initial staging of invasive ductal carcinoma (IDC) of the breast were reviewed. A total of 183 patients were included. SUVmax was correlated with the molecular subtypes defined by the St. Gallen Consensus Meeting 2013, i.e., luminal A-like (LA), luminal B-like HER2 negative (LBHER2-), luminal B-like HER2 positive (LBHER2+), HER2 positive (HER2+), and triple negative (TN), and with the clinicohistopathologic characteristics.
  
  
  RESULTS
  The molecular subtype was LA in 38 patients, LBHER2- in 72, LBHER2+ in 21, HER2+ in 30, and TN in 22. The mean SUVmax in the LA, LBHER2-, LBHER2+, HER2+, and TN groups were 4.5 ± 2.3, 7.2 ± 4.9, 7.2 ± 4.3, 10.2 ± 5.5, and 8.8 ± 7.1, respectively. Although SUVmax differed significantly among these subtypes (p< 0.001), the values showed a wide overlap. Optimal cut-off SUVmax to differentiate LA from LBHER2-, LBHER2+, HER2+ and TN were 5.9, 5.8, 7.5, and 10.2 respectively, with area under curve (AUC) of 0.648, 0.709, 0.833, and 0.697 respectively. The cut-off value of 5.9 yielded the highest accuracy for differentiation between the LA and non-LA subtypes, with sensitivity, specificity, and AUC of 79.4 %, 57.9 %, and 0.704 respectively.
  
  
  CONCLUSIONS
  The SUVmax showed a significant correlation with the molecular subtype. Although SUVmax measurements could be used along with immunohistochemical analysis for differentiating between molecular subtypes, its application to individual patients may be limited due to the wide overlaps in SUVmax.
authors.affiliation: Department of Nuclear Medicine, Busan Paik Hospital, University of Inje College of Medicine, 75 Bokji-ro, Busanjin-gu, Busan, 47392 Republic of Korea.
authors.forename: Sun Seong
authors.initials: SS
authors.lastname: Lee
authors.affiliation: Department of Nuclear Medicine, Haundae Paik Hospital, University of Inje College of Medicine, 875 Haeun-daero, Haeundae-gu, Busan, 48108 Republic of Korea.
authors.forename: Sang Kyun
authors.initials: SK
authors.lastname: Bae
authors.affiliation: Department of Nuclear Medicine, Busan Paik Hospital, University of Inje College of Medicine, 75 Bokji-ro, Busanjin-gu, Busan, 47392 Republic of Korea.
authors.forename: Yun Soo
authors.initials: YS
authors.lastname: Park
authors.affiliation: Department of Nuclear Medicine, Busan Paik Hospital, University of Inje College of Medicine, 75 Bokji-ro, Busanjin-gu, Busan, 47392 Republic of Korea.
authors.forename: Ji Sun
authors.initials: JS
authors.lastname: Park
authors.affiliation: Department of Surgery, Busan Paik Hospital, University of Inje College of Medicine, 75 Bokji-ro, Busanjin-gu, Busan, 47392 Republic of Korea.
authors.forename: Tae Hyun
authors.initials: TH
authors.lastname: Kim
authors.affiliation: Department of Pathology, Busan Paik Hospital, University of Inje College of Medicine, 75 Bokji-ro, Busanjin-gu, Busan, 47392 Republic of Korea.
authors.forename: Hye Kyoung
authors.initials: HK
authors.lastname: Yoon
authors.affiliation: Department of Pathology, Busan Paik Hospital, University of Inje College of Medicine, 75 Bokji-ro, Busanjin-gu, Busan, 47392 Republic of Korea.
authors.forename: Hyo Jung
authors.initials: HJ
authors.lastname: Ahn
authors.affiliation: Department of Nuclear Medicine, Busan Paik Hospital, University of Inje College of Medicine, 75 Bokji-ro, Busanjin-gu, Busan, 47392 Republic of Korea.
authors.forename: Seok Mo
authors.identifier: 0000-0003-4826-1368
authors.initials: SM
authors.lastname: Lee
keywords: Breast cancer; F-18 FDG PET/CT; Invasive ductal carcinoma; Molecular subtype; SUVmax