Open AccessComparison of four 3D conformal treatment techniques to optimise radiotherapy treatment for anal cancer
Author(s) -
Cray Alison,
Markham Cathy,
Ryan Michelle,
Herschtal Alan,
Ngan Samuel Y.,
Chander Sarat
Publication year - 2014
Publication title -
journal of medical radiation sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 18
eISSN - 2051-3909
pISSN - 2051-3895
DOI - 10.1002/jmrs.83
Subject(s) - medicine , contouring , nuclear medicine , anal cancer , diamond , cancer , materials science , composite material , engineering drawing , engineering
Abstract Introduction Chemoradiotherapy is the standard of care for anal cancer. Sizeable target volume leads to significant toxicity. We compared four different 3D conformal radiotherapy (3 DCRT ) techniques with the aim of finding the best technique to achieve the lowest dose to the organs at risk ( OAR ) without compromising the planning target volume ( PTV ) coverage. Methods Fifteen computed tomography ( CT ) data sets from previously treated anal cancer patients (five male and 10 female) were re‐contoured according to the Australasian Gastrointestinal Trials Group ( AGITG ) anal cancer contouring guidelines for N3 disease. Four different 3 DCRT plans for each CT data set (standard, V‐shape, diamond shape and alternate diamond shape) were generated. Comparisons of the radiation dose to non‐rectal bowel ( NRB ), urinary bladder, genitalia, and femurs were performed. Results V‐shape technique achieved significantly lower NRB V40 (mean = 59.6% SD = 11%) than diamond (63.8% SD = 13%), standard (63.8% SD = 11%) and alternate diamond (63.6% SD = 12%) techniques. V‐shape technique achieved the lowest mean bladder dose (mean = 45.3 Gy SD = 1.4 Gy). Diamond technique achieved the lowest femur V40 (mean = 32.4%) P < 0.001 for all comparisons between diamond and all other techniques. For genitalia V40, diamond technique (mean = 26.4% SD = 20%) and alternate diamond technique (mean = 27.6% SD = 20%) achieved significantly lower dose than V‐shape technique (mean = 43.2% SD = 26%) and standard technique (mean = 76.1% SD = 16%) P < 0.001 for all comparisons. Conclusions Sophisticated 3 DCRT techniques are superior to conventional techniques. Different 3 DCRT techniques provide varying levels of dose reduction to OAR , with none of the four techniques investigated capable of reducing dose to all OAR . A combination of techniques may provide the best solution. Further refinement of these techniques should be explored.