Intensity Modulated Arc Therapy in Bilaterally Irradiated Head and Neck Cancer: A Comparative and Prospective Multicenter Planning Study

Abstract

A dosimetric comparison was made of Helical Tomotherapy (HT) and Rapid'Arc(®) (RA) in 115 patients with head and neck carcinoma included in a prospective and multicentric study. HT and RA provided highly conformal plans that easily complied with dose volume constraints for organs at risk. HT reduced high doses to the planning target volumes (PTVs) compared to RA and provided a more homogeneous dose distribution but with an increased Non Tumoral Integral Dose (NTID) than RA. However, the clinical consequences of these dosimetric advantages and disadvantages need further investigation.

Clinical Outcomes of Several IMRT Techniques for Patients With Head and Neck Cancer: A Propensity Score–Weighted Analysis

“…This result was confirmed by standard multivariate regression analysis. This difference could be explained by the better dosimetric homogeneity of Tomo-Therapy, as we showed in the dosimetric analysis of this trial (5). However, no statistical difference was observed for PFS and OS.…”

“…We acknowledge that the main limitation of this trial was that it was not randomized. This study is the first, to our knowledge, to demonstrate the relative importance of the radiation delivery methods we use in patients in terms of dosimetry, cost, and clinical analysis (5,6), even within the field of IMRT. High-quality evidence for many of our treatment techniques is still very much lacking, and with new techniques constantly becoming available, it should not be considered trivial to create trials comparing novel delivery techniques, for example, in the field of stereotactic body radiation therapy.…”

“…However, IMRT can be delivered with different techniques, helical TomoTherapy and VMAT (SmartArc or RapidArc) being the most common. We have previously shown that, beyond different treatment planning requirements, these techniques had different costs (6,25,26) and their dosimetric output was also significantly different (4,5). What remained to be assessed was whether these differences actually translated into any meaningful clinical impact.…”

“…Several IMRT techniques are available: helical TomoTherapy and volumetric modulated arc therapy (VMAT) (Elekta SmartArc or RapidArc). These different modes result in dosimetric differences that were previously evaluated (4,5). TomoTherapy reduced high doses to the planning target volumes compared with Rap-idArc treatment and provided a more homogeneous dose distribution with an increased nontumoral integral dose.…”