Can a peri-rectal hydrogel spaceOAR programme for prostate cancer intensity-modulated radiotherapy be successfully implemented in a regional setting?
BACKGROUND
The aim of this study was to investigate whether the implementation of a hydrogel spacer (SpaceOAR) programme for patients treated with 81 Gy prostate intensity-modulated radiotherapy (IMRT) in a regional setting can reduce rectal doses and toxicity.


METHODS
In this retrospective study, 125 patients with localised prostate cancer treated between April 2014 (programme commencement) and June 2015 were compared: 65 with SpaceOAR (inserted by five different urologists) and 60 patients treated over the same time period without SpaceOAR. Patients were treated with 81 Gy in 45Fx of IMRT over 9 weeks. Planning aims included restricting rectal doses to V40 Gy < 35%, V65 Gy < 17%, V75 Gy < 10%. Acute toxicity was assessed weekly during radiotherapy and at 12 weeks.


RESULTS
Rectal volume parameters were all significantly lower in the SpaceOAR group, with an associated reduction in acute diarrhoea (13.8% vs 31.7%). There were no significant differences in the very low rates of acute and late faecal incontinence or proctitis, however, there was a trend towards increased haemorrhoid rate in the SpaceOAR group (11.7% vs 3.1%, P = 0.09).


CONCLUSIONS
A SpaceOAR programme in a regional setting with urologists performing low volumes of insertions (<1 per month on average) is of clinical benefit, and was associated with significantly lower radiation doses to the rectum and lower rates of acute diarrhoea.
Radiation Oncology, Mid-North Coast Cancer Institute, Coffs Harbour, New South Wales, Australia.
Bridget L
BL
Te Velde
Radiation Oncology, Mid-North Coast Cancer Institute, Coffs Harbour, New South Wales, Australia.
Justin
J
Westhuyzen
Radiation Oncology, Mid-North Coast Cancer Institute, Port Macquarie, New South Wales, Australia.
Nader
N
Awad
Radiation Oncology, Mid-North Coast Cancer Institute, Coffs Harbour, New South Wales, Australia.
Maree
M
Wood
Radiation Oncology, Mid-North Coast Cancer Institute, Coffs Harbour, New South Wales, Australia.
Thomas P
TP
Shakespeare
D000368:Aged; D057918:Fiducial Markers; D006801:Humans; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000008:administration & dosage*; D008297:Male; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy*; D011879:Radiotherapy Dosage; D050397:Radiotherapy, Intensity-Modulated; D012007:Rectum / Q000528:radiation effects*; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
D020136:Hydrogel, Polyethylene Glycol Dimethacrylate
hydrogel; intensity-modulated radiotherapy; prostate cancer