Computed tomogram prior to prostatectomy. Advantage in defining planning target volumes for postoperative adjuvant radiotherapy in patients with stage C prostate cancer?
OBJECTIVE
To evaluate the influence of a preoperative computed tomogram (CT) on delineation of the planning target volume (PTV) for adjuvant radiation therapy of pT3 pN0 prostate cancer.


METHODS
PTVs of ten patients who had an additional preoperative CT examination were contoured by three independent radiation oncologists. PTV included the former prostatic bed and seminal vesicles with a safety margin. First PTVs were drawn without knowledge of the preoperative CTs and in a second attempt, this procedure was repeated with these CTs available for visual comparison. Changes in PTV dimensions for every patient were analyzed.


RESULTS
In 93% of all PTVs there was a decision to increase the PTV after viewing the preoperative CT images. Mean PTV length increased from 7.3 to 8.4 cm and PTV volumes expanded 26% from 244 to 308 cm3. These differences were statistically significant for all three participating radiation oncologists.


CONCLUSIONS
Planning target volume definition probably is a critical factor in adjuvant radiation therapy after radical prostatectomy. As there is a considerable incertainty in PTV definition a preoperative CT is helpful and therefore may have beneficial influence on results.
Höcht
Stefan
S
Klinik für Radioonkologie und Strahlentherapie des Universitätsklinikums Benjamin Franklin, Freie Universität Berlin, Germany. hoecht@ukbf.fu-berlin.de
Wiegel
Thomas
T
Bottke
Dirk
D
Jentsch
Hilmar
H
Sternemann
Maria
M
Rosenthal
Peter
P
Hinkelbein
Wolfgang
W
D006801:Humans; D008297:Male; D009367:Neoplasm Staging; D015588:Observer Variation; D010348:Patient Care Team; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D011880:Radiotherapy Planning, Computer-Assisted; D018714:Radiotherapy, Adjuvant; D014057:Tomography, X-Ray Computed