title: Distribution patterns of metastatic pelvic lymph nodes assessed by CT/MRI in patients with uterine cervical cancer.
abstract: BACKGROUND
  To investigate the three-dimensional (3D) distribution patterns of clinically metastatic (positive) lymph nodes on pretreatment computed tomography (CT)/magnetic resonance imaging (MRI) images of patients with locally advanced cervical cancer.
  
  
  METHODS
  We enrolled 114 patients with uterine cervical cancer with positive nodes by CT/MRI (≥10 mm in the shortest diameter). Pretreatment CT/MRI data were collected at 6 institutions. The FIGO stage was IB1 in 2 patients (2%), IB2 in 6 (5%), IIA in 3 (3%), IIB in 49 (43%), IIIB in 50 (44%), and IVA in 4 (4%) patients. The median cervical tumor diameter assessed by T2-weighted MRI was 55 mm (range, 10-87 mm). The anatomical distribution of the positive nodes was evaluated on CT/MRI images by two radiation oncologists and one diagnostic radiologist.
  
  
  RESULTS
  In these patients, 273 enlarged nodes were assessed as positive. The incidence of positive nodes was 104/114 (91%) for the obturator region, 31/114 (27%) for the external iliac region, 16/114 (14%) for the internal iliac region, 22/114 (19%) for the common iliac region, and 6/114 (5%) for the presacral region. The external iliac region was subdivided into four sub-regions: lateral, intermediate, medial, and caudal. The obturator region was subdivided into two sub-regions: cranial and caudal. The majority of patients had positive nodes in the cranial obturator and/or the medial external iliac region (111/114). In contrast, few had positive nodes in the lateral external iliac, caudal external iliac, caudal obturator, internal iliac and presacral regions. All cases with positive nodes in those low-risk regions also had positive nodes in other pelvic nodal regions concomitantly. The incidence of positive nodes in the low-risk regions/sub-regions was significantly related to FIGO stage (p=0.017) and number of positive nodes (p<0.001).
  
  
  CONCLUSIONS
  We demonstrated the 3D distribution patterns of clinical metastatic pelvic lymph nodes on pretreatment CT/MRI images of patients with locally advanced cervical cancer. These findings might contribute to future individualization of the clinical target volume of the pelvic nodes in patients with cervical cancer.
authors.affiliation: Department of Radiology, Graduate School of Medical Science, University of the Ryukyus, Okinawa, Japan. k108711@eve.u-ryukyu.ac.jp
authors.forename: Goro
authors.initials: G
authors.lastname: Kasuya
authors.forename: Takafumi
authors.initials: T
authors.lastname: Toita
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Furutani
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kodaira
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Ohno
authors.forename: Yuko
authors.initials: Y
authors.lastname: Kaneyasu
authors.forename: Ryouichi
authors.initials: R
authors.lastname: Yoshimura
authors.forename: Takashi
authors.initials: T
authors.lastname: Uno
authors.forename: Akira
authors.initials: A
authors.lastname: Yogi
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ishikura
authors.forename: Masahiro
authors.initials: M
authors.lastname: Hiraoka
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D064847:Multimodal Imaging; D009367:Neoplasm Staging; D010388:Pelvis; D014057:Tomography, X-Ray Computed; D002583:Uterine Cervical Neoplasms / Q000473:pathology*