title: Impact of tumour invasion on seminal vesicles mobility in radiotherapy of prostate cancer.
abstract: OBJECTIVE
  Mobility of the seminal vesicles relative to the prostate challenges adequate dose coverage. The aim of this study was to assess the impact of tumour invasion on SV mobility.
  
  
  METHODS
  Three groups of 30 prostate cancer patients with (1) no invasion on MR, (2) minimal invasion (<5mm), and (3) extensive invasion (>5mm) were studied. Translations and rotations of the SV were measured with CBCT and compared between the three groups.
  
  
  RESULTS
  In the extensive group the random SV translations were significantly lower in comparison with the no invasion group in the LR: 0.15 vs 0.16 cm (p=0.015), CC: 0.17 vs 0.23 cm (p=0.004) and AP direction: 0.19 vs 0.26 cm (p=0.002). Also the random SV rotation on the LR axis was significantly lower: 5.2 vs 6.3° (p=0.035). In comparison with the minimal invasion group the random SV translations were significantly lower in the extensive group in the CC: 0.17 vs 0.24 cm (p=0.001) and AP direction 0.19 vs 0.31 cm (p=0.007) and for the rotation on the LR axis: 5.2 vs 6.5° (p=0.043).
  
  
  CONCLUSIONS
  Increasing tumour invasion in the SV reduces the mobility of the SV, however the mobility remains considerable.
authors.affiliation: Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
authors.forename: Monica
authors.initials: M
authors.lastname: van der Burgt
authors.affiliation: Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
authors.forename: Laura
authors.initials: L
authors.lastname: Bergsma
authors.affiliation: Department of Radiation Oncology, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: Jeroen
authors.initials: J
authors.lastname: de Vries
authors.affiliation: Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
authors.forename: Floris J
authors.initials: FJ
authors.lastname: Pos
authors.affiliation: Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
authors.forename: Robin
authors.initials: R
authors.lastname: Kalisvaart
authors.affiliation: Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
authors.forename: Wilma
authors.initials: W
authors.lastname: Heemsbergen
authors.affiliation: Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
authors.forename: Peter
authors.initials: P
authors.lastname: Remeijer
authors.affiliation: Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands. Electronic address: u.vd.heide@nki.nl.
authors.forename: Uulke A
authors.initials: UA
authors.lastname: van der Heide
mesh_terms: D006801:Humans; D008297:Male; D009361:Neoplasm Invasiveness; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D012669:Seminal Vesicles / Q000503:physiopathology* / Q000528:radiation effects*
keywords: ART; Inter-fraction organ motion; Prostate radiotherapy; SV invasion