Department of Oncology, Helsinki University Central Hospital, Helsinki, Finland.
To evaluate the benefits of adaptive radiotherapy for bladder cancer in decreasing irradiation of small bowel.
Five patients with muscle invasive bladder cancer received adaptive radiotherapy to a total dose of 55.8-65Gy with daily cone-beam computed tomography scanning. The whole bladder was treated to 45-50.4Gy, followed by a partial bladder boost. The plan of the day was chosen from 3 to 4 pre-planned treatment plans according to the visible extent of bladder wall in cone-beam computed tomography images. Dose volume histograms for intestinal cavity volumes were constructed and compared with corresponding histograms calculated for conventional non-adaptive radiotherapy with single treatment plan of 2cm CTV-PTV margins. CTV dose coverage in adaptive treatment technique was compared with CTV dose coverage in conventional radiotherapy.
The average volume of intestinal cavity receiving⩾45Gy was reduced from 335±106cm(3) to 180±113cm(3) (1SD). The maximum volume of intestinal cavity spared at 45Gy on a single patient was 240cm(3), while the minimum volume was 65cm(3). The corresponding reduction in average intestinal cavity volume receiving⩾45Gy calculated for the whole bladder treatment only was 66±36cm(3). CTV dose coverage was improved on two out of five patients and decreased on three patients.
Adaptive radiotherapy considerably reduces dose to the small bowel, while maintaining the dose coverage of CTV at similar level when compared to the conventional treatment technique.
Written by:
Tuomikoski L, Collan J, Keyriläinen J, Visapää H, Saarilahti K, Tenhunen M. Are you the author?
Reference: Radiother Oncol. 2011 Mar 21. Epub ahead of print.
PubMed Abstract
PMID: 21429607
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