The Incidence of Inclusion of the Sigmoid Colon and Small Bowel in the Planning Target Volume in Radiotherapy for Prostate Cancer

Abstract

When systematically investigating the anatomic position of sigmoid colon and small bowel in patients accepted for prostate irradiation, parts of both organs were often observed in close vicinity to the PTV. Apart from the rectum, these organs may be dose-limiting in prostate radiotherapy.

Variability in Bladder Volumes of Full Bladders in Definitive Radiotherapy for Cases of Localized Prostate Cancer

“…In order to improve bladder volume consistency when the goal is to maintain a full bladder, many institutions specify the volume of liquids to be consumed and the times at which such liquids should be consumed (e.g., drink 500 ml of fluid an hour before the planning CT scan and treatment) [1,5,15,19,22]. However, large variations in bladder volume have been reported with such protocols [1].…”

“…One possible advantage of maintaining a full bladder is that part of the bladder is moved away from the target volume, thus, reducing bladder toxicity [6,11,12]. Moreover, a full bladder moves the small intestine and the sigmoid colon out of the irradiation field, also reducing toxicity in these organs [3,5,10,13]. For these reasons, we ask patients scheduled to undergo irradiation for prostate cancer to maintain a full bladder during irradiation.…”

Dose-Response Relations for Anal Sphincter Regarding Fecal Leakage and Blood or Phlegm in Stools after Radiotherapy for Prostate Cancer

“…The clinical target volume (CTV) was not distin- (13) guished from the GTV. The planning target volume (PTV) was derived from the CTV by adding a 2-cm margin around it apart from the apex, where the margin was 2.5 cm to allow positioning and mobility uncertainties concerning the microscopic spread outside the CTV [1,15,43]. The rectum was defined anatomically as extending from the sigmoid flexure to the anal verge.…”

The sigmoid colon and bladder shielding in whole pelvic irradiation at prostate cancer (forward planned IMRT from Institute of Oncology Ljubljana)

“…6,7 We are also respecting that more than half of urinary bladder should not receive doses higher than 70 Gy (V70<50%). Since the stricter dose constraints on bladder, that prevent G1 and G2 toxicity, 8,9 cannot be respected, applying WPI, the chosen restrictions are set to prevent G3 toxicity.…”