[Impact of dynamic IMRT and tomotherapy in pelvic cancers: a prospective dosimetric study with 51 patients]

Abstract

Purpose: To compare the dosimetric results of different techniques of dynamic intensity modulated radiation therapy (IMRT) in patients treated for a pelvic cancer with nodal irradiation.

Patients and methods: Data of 51 patients included prospectively in the Artpelvis study were analyzed. Thirty-six patients were treated for a high-risk prostate cancer (13 with helical tomotherapy, and 23 with Rapid'Arc(®)) and 15 patients were treated for a localized anal cancer (nine with helical tomotherapy and six with Rapid'Arc(®)). Plan quality was assessed according to several different dosimetric indexes of coverage of planning target volume and sparing of organs at risk.

Results: Although some dosimetric differences were statistically significant, helical tomotherapy and Rapid'Arc provided very similar and highly conformal plans. Regarding organs at risk, Rapid'Arc(®) provided better pelvic bone sparing with a lower non-tumoral integral dose.

Conclusion: In pelvis cancer with nodal irradiation, Rapid'Arc and helical tomotherapy provided very similar plans. The clinical evaluation of Artpelvis study will verify this equivalence hypothesis.

Keywords: Comparaison dosimétrique; Dosimetric comparison; Dynamic IMRT; Pelvic radiotherapy; RCMI rotationnelle; Radiothérapie pelvienne; Rapid’Arc(®); Tomotherapy; Tomothérapie hélicoïdale.