Development of RTOG Consensus Guidelines for the Definition of the Clinical Target Volume for Postoperative Conformal Radiation Therapy for Prostate Cancer
Received 7 August 2008; received in revised form 29 January 2009; accepted 3 February 2009. published online 24 April 2009.
Purpose
To define a prostate fossa clinical target volume (PF-CTV) for Radiation Therapy Oncology Group (RTOG) trials using postoperative radiotherapy for prostate cancer.
Methods and Materials
An RTOG-sponsored meeting was held to define an appropriate PF-CTV after radical prostatectomy. Data were presented describing radiographic failure patterns after surgery. Target volumes used in previous trials were reviewed. Using contours independently submitted by 13 radiation oncologists, a statistical imputation method derived a preliminary “consensus” PF-CTV.
Results
Starting from the model-derived CTV, consensus was reached for a CT image–based PF-CTV. The PF-CTV should extend superiorly from the level of the caudal vas deferens remnant to >8–12 mm inferior to vesicourethral anastomosis (VUA). Below the superior border of the pubic symphysis, the anterior border extends to the posterior aspect of the pubis and posteriorly to the rectum, where it may be concave at the level of the VUA. At this level, the lateral border extends to the levator ani. Above the pubic symphysis, the anterior border should encompass the posterior 1–2 cm of the bladder wall; posteriorly, it is bounded by the mesorectal fascia. At this level, the lateral border is the sacrorectogenitopubic fascia. Seminal vesicle remnants, if present, should be included in the CTV if there is pathologic evidence of their involvement.
Conclusions
Consensus on postoperative PF-CTV for RT after prostatectomy was reached and is available as a CT image atlas on the RTOG website. This will allow uniformity in defining PF-CTV for clinical trials that include postprostatectomy RT.
Reprint requests to: Jeff Michalski, M.D., Professor and Head, Department of Radiation Oncology, Washington University School of Medicine, 4921 Parkview Place, Campus box 8224, St. Louis, Missouri 63110. Tel: (314) 362-2856; Fax: (314) 747-9557
Supported by grants from the National Cancer Institute, CA21661, CA32115, and CA37422
ABSTRACT