title: Intensity modulated radiotherapy for high risk prostate cancer based on sentinel node SPECT imaging for target volume definition.
abstract: BACKGROUND
  The RTOG 94-13 trial has provided evidence that patients with high risk prostate cancer benefit from an additional radiotherapy to the pelvic nodes combined with concomitant hormonal ablation. Since lymphatic drainage of the prostate is highly variable, the optimal target volume definition for the pelvic lymph nodes is problematic. To overcome this limitation, we tested the feasibility of an intensity modulated radiation therapy (IMRT) protocol, taking under consideration the individual pelvic sentinel node drainage pattern by SPECT functional imaging.
  
  
  METHODS
  Patients with high risk prostate cancer were included. Sentinel nodes (SN) were localised 1.5-3 hours after injection of 250 MBq 99mTc-Nanocoll using a double-headed gamma camera with an integrated X-Ray device. All sentinel node localisations were included into the pelvic clinical target volume (CTV). Dose prescriptions were 50.4 Gy (5 x 1.8 Gy / week) to the pelvis and 70.0 Gy (5 x 2.0 Gy / week) to the prostate including the base of seminal vesicles or whole seminal vesicles. Patients were treated with IMRT. Furthermore a theoretical comparison between IMRT and a three-dimensional conformal technique was performed.
  
  
  RESULTS
  Since 08/2003 6 patients were treated with this protocol. All patients had detectable sentinel lymph nodes (total 29). 4 of 6 patients showed sentinel node localisations (total 10), that would not have been treated adequately with CT-based planning ('geographical miss') only. The most common localisation for a probable geographical miss was the perirectal area. The comparison between dose-volume-histograms of IMRT- and conventional CT-planning demonstrated clear superiority of IMRT when all sentinel lymph nodes were included. IMRT allowed a significantly better sparing of normal tissue and reduced volumes of small bowel, large bowel and rectum irradiated with critical doses. No gastrointestinal or genitourinary acute toxicity Grade 3 or 4 (RTOG) occurred.
  
  
  CONCLUSIONS
  IMRT based on sentinel lymph node identification is feasible and reduces the probability of a geographical miss. Furthermore, IMRT allows a pronounced sparing of normal tissue irradiation. Thus, the chosen approach will help to increase the curative potential of radiotherapy in high risk prostate cancer patients.
authors.affiliation: Department of Radiation Oncology, University of Tübingen, Tübingen, Germany. ute.ganswindt@med.uni-tuebingen.de
authors.forename: Ute
authors.initials: U
authors.lastname: Ganswindt
authors.forename: Frank
authors.initials: F
authors.lastname: Paulsen
authors.forename: Stefan
authors.initials: S
authors.lastname: Corvin
authors.forename: Kai
authors.initials: K
authors.lastname: Eichhorn
authors.forename: Stefan
authors.initials: S
authors.lastname: Glocker
authors.forename: Ilse
authors.initials: I
authors.lastname: Hundt
authors.forename: Mattias
authors.initials: M
authors.lastname: Birkner
authors.forename: Markus
authors.initials: M
authors.lastname: Alber
authors.forename: Aristotelis
authors.initials: A
authors.lastname: Anastasiadis
authors.forename: Arnulf
authors.initials: A
authors.lastname: Stenzl
authors.forename: Roland
authors.initials: R
authors.lastname: Bares
authors.forename: Wilfried
authors.initials: W
authors.lastname: Budach
authors.forename: Michael
authors.initials: M
authors.lastname: Bamberg
authors.forename: Claus
authors.initials: C
authors.lastname: Belka
mesh_terms: D000368:Aged; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011874:Radiometry; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D020266:Radiotherapy, Conformal / Q000379:methods; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D012306:Risk; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D014057:Tomography, X-Ray Computed