title: Follow-up bone scan in breast cancer patients: what is the appropriate interpretation of purely rib uptake?
abstract: OBJECTIVE
  Although rib uptake is frequently detected in follow-up bone scans of breast cancer patients, few studies have assessed its clinical significance.
  
  
  METHODS
  Among 1208 breast cancer patients who underwent a bone scan between 2011 and 2014, 157 patients presented with newly detected rib uptake at follow-up. Patients who had underlying bone metastases (n=8) or had simultaneous new uptake in sites other than the rib (n=13) were excluded. The patients enrolled finally were those who had purely rib uptakes. The location, intensity, and final diagnosis of the uptake were evaluated by nuclear medicine physicians.
  
  
  RESULTS
  A total of 275 new instances of rib uptake were detected in follow-up bone scans of 136 patients. These were more frequently located on the ipsilateral side of the breast cancer (61.1%) and the anterior arc (65.1%), and they presented as moderate to intense (93.1%) uptakes. Among these, 265 lesions in 130 patients turned out to be benign fractures (96.4%), whereas only 10 lesions in six patients were metastases. The proportion of metastases was significantly higher if the uptake was linear or if the patient had recurrence. It was marginally higher if the uptake was located in the posterior arc. The proportion of metastases within the radiation field was significantly lower in patients with a history of irradiation.
  
  
  CONCLUSIONS
  Newly detected purely rib uptake on a follow-up bone scan in patients who have been treated for breast cancer is mostly because of fractures and rarely signals metastasis. However, if the patient has disease recurrence, metastasis should strongly be suspected, particularly when uptake is linear or located in the posterior arc.
authors.affiliation: Departments of aNuclear Medicine bSurgery cHematology and Oncology dRadiation Oncology ePathology fRadiology, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan gDepartment of Nuclear Medicine, Kosin University Gospel Hospital, Kosin University College of Medicine, Busan, Korea.
authors.forename: Minjung
authors.initials: M
authors.lastname: Seo
authors.forename: Byung Kyun
authors.initials: BK
authors.lastname: Ko
authors.forename: Soon Young
authors.initials: SY
authors.lastname: Tae
authors.forename: Su-Jin
authors.initials: SJ
authors.lastname: Koh
authors.forename: Young Ju
authors.initials: YJ
authors.lastname: Noh
authors.forename: Hye-Jeong
authors.initials: HJ
authors.lastname: Choi
authors.forename: Kyungkyg
authors.initials: K
authors.lastname: Bae
authors.forename: Minseo
authors.initials: M
authors.lastname: Bang
authors.forename: Sungmin
authors.initials: S
authors.lastname: Jun
authors.forename: Seol Hoon
authors.initials: SH
authors.lastname: Park
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001859:Bone Neoplasms / Q000000981:diagnostic imaging* / Q000556:secondary*; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D018567:Breast Neoplasms, Male / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012253:Rib Fractures / Q000000981:diagnostic imaging; D012272:Ribs / Q000000981:diagnostic imaging*