Prostate bed localization with image-guided approach using on-board imaging: reporting acute toxicity and implications for radiation therapy planning following prostatectomy.
OBJECTIVE
To report our experience using Image-Guided Radiation Therapy (IGRT) in patients undergoing post-prostatectomy irradiation.


METHODS
Twenty-six patients were treated with radiotherapy following radical prostatectomy using Intensity Modulated Radiation Therapy (IMRT). Prostate bed localization was done using image guidance to align surgical clips relative to the reference isocenter on the planning digitally reconstructed radiographs. Assuming surgical clips to be surrogate for prostate bed, daily shifts in their position were calculated after aligning with the bony anatomy. Shifts were recorded in three dimensions. The acute toxicity was measured during and after completion of treatment.


RESULTS
The average (standard deviation) prostate bed motion in anterior-posterior, superior-inferior and left-right directions were: 2.7mm (2.1), 2.4mm (2.1) and 1.0mm (1.7), respectively. The majority of patients experienced only grade 1 symptoms, two patients had grade 2 symptoms and none had grade 3 or higher acute toxicity.


CONCLUSIONS
Daily IGRT is recommended for accurate target localization during radiation delivery to improve efficacy of treatment and enhance therapeutic ratio. Larger studies with longer follow-up are necessary to make definitive recommendations regarding magnitude of margin reduction around clinical target volume.
Department of Radiation Oncology, Division of Urology and Medical Oncology, University of California, San Diego Medical Center, La Jolla, CA 92093-0843, USA. apsandhu@ucsd.edu
Ajay
A
Sandhu
Rajni
R
Sethi
Roger
R
Rice
Jia-Zhu
JZ
Wang
Logan
L
Marcus
Carol
C
Salem
Tracy
T
Downs
J Kellogg
JK
Parsons
Fred
F
Millard
Todd
T
Pawlicki
Arno
A
Mundt
D000368:Aged; D006801:Humans; D008297:Male; D008875:Middle Aged; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery*; D015641:Radiography, Interventional; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D018714:Radiotherapy, Adjuvant / Q000009:adverse effects / Q000379:methods*; D016879:Salvage Therapy; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome