A treatment planning study comparing helical tomotherapy with intensity-modulated radiotherapy for the treatment of anal cancer☆
Received 26 November 2008; received in revised form 28 September 2009; accepted 3 October 2009. published online 06 November 2009.
Abstract
Purpose
A planning study to compare helical tomotherapy (HT) and intensity-modulated radiotherapy (IMRT) for the treatment of anal canal cancer.
Materials and methods
Sixteen (8 males and 8 females) patients with anal cancer previously treated radically were identified. HT and IMRT plans were generated and dosimetric comparisons of the plans were performed. The planning goals were to deliver 54Gy to the tumor (PTV54Gy) and 48Gy to the nodes at risk (PTVNode) in 30 fractions.
Results
PTVs: HT plans were more homogeneous for both men and women. Male patients: HT vs. IMRT: Dmax: 55.87±0.58 vs. 59.17±3.24 (p=0.036); Dmin: 52.91±0.36 vs. 44.09±6.84 (p=0.012); female patients: HT vs. IMRT: Dmax: 56.14±0.71 vs. 59.47±0.81 (p=0.012); Dmin: 52.36±0.87 vs. 50.97±1.42 (p=0.028). OARs: In general, HT plans delivered a lower dose to the peritoneal cavity, external genitalia and the bladder and IMRT plans resulted in greater sparing of the pelvic bones (iliac crest/femur) for both men and women. Iliac crest/femur: the difference was significant only for the mean V10Gy of iliac crest in women (p⩽0.012). External genitalia: HT plans achieved better sparing in women compared to men (p⩽0.046). For men, the mean doses were 18.96±3.17 and 15.72±3.21 for the HT and IMRT plan, respectively (p⩽0.017). Skin: both techniques achieved comparable sparing of the non-target skin (p=NS).
Conclusions
HT and IMRT techniques achieved comparable target dose coverage and organ sparing, whereas HT plans were more homogeneous for both men and women.
ABSTRACT