OBJECTIVE: There remains concern regarding the use of fiducial-based image-guided radiotherapy (IGRT) in patients with high-risk prostate cancer also undergoing intensity-modulated radiotherapy (IMRT) to pelvic nodes. By a retrospective study, we aim to ascertain the impact of the use of fiducial-based IGRT on lymph node planned target volume (PTV) coverage. METHODS: 30 consecutive IMRT prostate and pelvic node plans were reviewed, and dose was recalculated with 1-mm increment movements in anterior, posterior, superior, inferior, right and left directions up to 10 mm. All patients were treated with a full bladder after drinking 450-750 ml of water and empty rectum with the use of sodium citrate enemas daily. Dose-volume histogram parameters were recorded at each position, specifically nodal PTV V95%, V99% and V100%. A local IGRT database was used to identify the likelihood of a particular bony to fiducial offset in all directions. The combined data were used to calculate the percentage risk of underdosing the lymph node PTV on any given fraction. RESULTS: The likelihood of an offset in the left, right and anterior directions occurring and resulting in a failure to cover the PTV was <0.25%. The likelihood of a posterior offset occurring and resulting in inadequate coverage was slightly higher but remained <1%. CONCLUSION: This study confirms the safety of fiducial-based image-guided IMRT (IG-IMRT) with a strict bowel and bladder protocol, allowing a reduction of the clinical target volume to PTV margin of the prostate volume and consequent reduction in rectal toxicity. ADVANCES IN KNOWLEDGE: This study strengthens the evidence supporting the safe implementation of fiducial-based IG-IMRT treating the prostate and pelvic nodes in high-risk prostate cancer.
OBJECTIVE: There remains concern regarding the use of fiducial-based image-guided radiotherapy (IGRT) in patients with high-risk prostate cancer also undergoing intensity-modulated radiotherapy (IMRT) to pelvic nodes. By a retrospective study, we aim to ascertain the impact of the use of fiducial-based IGRT on lymph node planned target volume (PTV) coverage. METHODS: 30 consecutive IMRT prostate and pelvic node plans were reviewed, and dose was recalculated with 1-mm increment movements in anterior, posterior, superior, inferior, right and left directions up to 10 mm. All patients were treated with a full bladder after drinking 450-750 ml of water and empty rectum with the use of sodium citrate enemas daily. Dose-volume histogram parameters were recorded at each position, specifically nodal PTV V95%, V99% and V100%. A local IGRT database was used to identify the likelihood of a particular bony to fiducial offset in all directions. The combined data were used to calculate the percentage risk of underdosing the lymph node PTV on any given fraction. RESULTS: The likelihood of an offset in the left, right and anterior directions occurring and resulting in a failure to cover the PTV was <0.25%. The likelihood of a posterior offset occurring and resulting in inadequate coverage was slightly higher but remained <1%. CONCLUSION: This study confirms the safety of fiducial-based image-guided IMRT (IG-IMRT) with a strict bowel and bladder protocol, allowing a reduction of the clinical target volume to PTV margin of the prostate volume and consequent reduction in rectal toxicity. ADVANCES IN KNOWLEDGE: This study strengthens the evidence supporting the safe implementation of fiducial-based IG-IMRT treating the prostate and pelvic nodes in high-risk prostate cancer.
Authors: R C Zellars; P L Roberson; M Strawderman; D Zhang; H M Sandler; R K Ten Haken; D Osher; P W McLaughlin Journal: Int J Radiat Oncol Biol Phys Date: 2000-06-01 Impact factor: 7.038
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Authors: R K Ten Haken; J D Forman; D K Heimburger; A Gerhardsson; D L McShan; C Perez-Tamayo; S L Schoeppel; A S Lichter Journal: Int J Radiat Oncol Biol Phys Date: 1991-06 Impact factor: 7.038
Authors: S O Asbell; K L Martz; K H Shin; W T Sause; R L Doggett; C A Perez; M V Pilepich Journal: Int J Radiat Oncol Biol Phys Date: 1998-03-01 Impact factor: 7.038
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Authors: Aart J Nederveen; Homan Dehnad; Uulke A van der Heide; R Jeroen A van Moorselaar; Pieter Hofman; Jan J W Lagendijk Journal: Radiother Oncol Date: 2003-07 Impact factor: 6.280
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