ABSTRACT
Objective
The use of conformal radiation therapy in the treatment of carcinoma of the prostate has
allowed for dose escalation and improved local control. The dose to the rectum is an
important consideration in determining complication rates. This study aims to evaluate
the effect of a Foleys rectal catheter balloon on the dose volume histograms to the rectum
and to assess the effect of the balloon catheter on prostate gland immobilization during
treatment of intermediate risk cancer of the prostate.
Design and methods
Ten patients with intermediate risk prostate cancer, each acting as his own control, were
recruited in the study; eight patients had complete data for analysis. CT scans were done
at intervals during treatment, with and without a rectal balloon filled with 30 ml of
contrast. 3 pairs of CT scans for each patient were performed and were available for
analysis. All patients were treated with 6-field conformal radiotherapy up to 66 Gy
followed by a boost of 12 Gy in 3 fractions to the prostate using a rectal balloon and a 3-
field plan. Dose volume histograms were calculated for the boost plan with and without
the rectal balloon. Movements of the prostate in the superior-inferior and the anteriorposterior
directions were measured with and without the balloon for each treatment. There was a slight reduction in the dose received by 1% and 2 % of the rectal volume
with the balloon (55% and 52% respectively), compared to without a balloon (57% and
54.3% respectively) (p> 0.05). Results There was a non significant increase in the dose received
by 50% of the rectum (p>0.05) with the use of the rectal balloon due to the rectum being
pushed towards the symphysis pubis by the balloon.
With the use of rectal balloon, the superior / inferior displacement of the prostate was
reduced (p=0.04) and a displacement of more than 5 mm was observed in one out of eight
patients. The anterior / posterior displacement of the prostate was decreased with the
rectal balloon with a mean of 4 mm compared to 5 mm with no rectal balloon. This was
not statistically significantly (p>0.05). However, displacement of more than 5 mm was
observed in 2 patients with the rectal balloon. No grade 3 acute rectal toxicity was
recorded in the 8 patients. Conclusion
There was no significant change in the percentage dose received by the rectum with the
use of the rectal balloon in this study. The study showed however that the rectal balloon
significantly reduced prostate movement during treatment.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:wits/oai:wiredspace.wits.ac.za:10539/5759 |
| Date | 15 October 2008 |
| Creators | Kanyike, Daniel Mukasa |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | application/pdf |
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