title: Breast cancer recurrence according to molecular subtype.
abstract: BACKGROUND
  To evaluate the location of tumor relapse and imaging modality for detection according to the breast cancer subtype: luminal A, luminal B, HER2 positive luminal B, nonluminal HER2 positive, and triple negative.
  
  
  METHODS
  A total of 1244 patients with breast cancer with known estrogen receptor (ER), progesterone receptor (PR), Ki-67 and human epidermal growth factor receptor 2 (HER2), who underwent breast surgery from 2009 to 2012 were analyzed. Patients were classified into the following categories: luminal A (n=458), luminal B (n=241), HER2 positive luminal B (n=227), nonluminal HER2 positive (n=145) and triple negative (n=173). A total of 105 cases of relapse were detected in 102 patients: locoregional recurrence (n=46), recurrence in the contralateral breast (n=28) and distant metastasis (n=31). Comparison of proportions was used to determine the difference between subtypes.
  
  
  RESULTS
  Relapse rates by subtypes are as follows: luminal A 23 of 458 (5.02%), luminal B 19 of 241 (7.88%), HER2 positive luminal B 15 of 227 (6.61%), nonluminal HER2 postive 19 of 145 (13.10%) and triple negative 29 of 173 (16.76%). Luminal A tumors had the lowest rate of recurrence and had significantly lower recurrence rate in comparison with nonluminal HER2 postive (p=0.0017) and triple negative subtypes (p<0.0001). Compared with all other subtypes except nonluminal HER2 positive, triple negative tumors had the highest rate of tumor recurrence (p<0.01). Triple negatives were most likely to develop contralateral recurrence against all subtypes (p<0.05). Detection rate of locoregional and contralateral tumor recurrence were 28.3% on mammography (n=17/60).
  
  
  CONCLUSIONS
  Luminal A tumors are associated with a low risk of recurrence while triple negative lesions have a high risk. In case of triple negative tumors, the contralateral breast has much more recurrence as compared with all other subtype. In terms of detection rates, breast USG was the best modality for detecting tumor recurrence, compared with other modalities (p<0.05). Subtyping of breast tumors using a molecular gene expression panel can identify patients who have increased risk of recurrence and allow prediction of locations of tumor recurrence for each subtype.
authors: Department of Radiology, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea E-mail : rad-ksh@catholic.ac.kr.
authors: Hee Jin
authors: HJ
authors: Shim
authors: Sung Hun
authors: SH
authors: Kim
authors: Bong Joo
authors: BJ
authors: Kang
authors: Byung Gil
authors: BG
authors: Choi
authors: Hyeon Sook
authors: HS
authors: Kim
authors: Eun Suk
authors: ES
authors: Cha
authors: Byung Joo
authors: BJ
authors: Song
mesh_terms: D000328:Adult; D014408:Biomarkers, Tumor / Q000378:metabolism; D005260:Female; D006801:Humans; D019394:Ki-67 Antigen / Q000378:metabolism; D008207:Lymphatic Metastasis / Q000473:pathology*; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology* / Q000473:pathology*; D011859:Radiography; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D064726:Triple Negative Breast Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery
chemical_list: D014408:Biomarkers, Tumor; D019394:Ki-67 Antigen; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; C508053:ERBB2 protein, human