A dosimetric study of electron beam therapy vs. high-dose-rate mould brachytherapy in adjuvant treatment of non-melanoma skin carcinomas of the head and neck region

Abstract

Purpose: Radiation for superficial tumours of the head and neck region can be given either by brachytherapy or electrons. Brachytherapy (BT), due to rapid dose fall-off and minor setup errors, should be superior to external beam radiotherapy (EBRT) for treatment of lesions in difficult locations such as the nose and earlobe. The present study is a dosimetric comparison of computed tomography (CT)-based mould brachytherapy treatment plans with 3D conformal electron beam therapy in the treatment of non-melanoma skin cancers (NMSC). Material and methods: From December 2017 to November 2018 10 patients with NMSC of the head and neck region (forehead, nose, cheek) who underwent adjuvant radiation with HDR brachytherapy (BT) with a surface mould individual applicator were enrolled for analysis. We evaluated dose coverage by minimal dose to 90% of planning target volume (PTV, D 90), volumes of PTV receiving 90-150% of prescribed dose (PD) (VPTV 90-150), conformal index for 90% and 100% of PD (COIN 90 , COIN 100), dose homogeneity index (DHI), dose nonuniformity ratio (DNR), and exposure of organs at risk (OARs) (eyes, lens, underlying bone and skin). Prospectively, we created CT-based treatment plans for electron beam therapy. We compared conformity (COIN 90 , COIN 100), dose coverage of PTV (D 90 , VPTV 90 , VPTV 100), volumes of body receiving 10-90% of PD (V 10-V 90), doses to OARs (D 0.1cc and D 2cc) of BT and electron plans. Results: We obtained mean BT-DHI 0.81, BT-DNR 0.608, Electron-DHI 1.25. We observed no significant differences in VPTV 90,100 and D 90 between BT and electron beam. Mean BT-VPTV 125,150 were significantly higher than Electron-VPTV 100,125. COIN 90 was superior for BT plans. Conclusions: CT-based surface mould brachytherapy results in better conformity of superficial lesions on small, irregular surfaces such as the nose and inner canthus than electrons with a slightly higher skin dose.

High-dose-rate brachytherapy using Leipzig applicators for non-melanoma localized skin cancer

“…Souransu et al . reported much better conformity with HDR when compared to electrons in these situations [ 19 ]. Furthermore, the use of HDR has some advantages over other techniques: Leipzig-style applicators are easily placed, personal radioprotection of patient is maintained, with no isolation required, and HDR can be performed on an outpatient basis.…”

Brachytherapy in the Treatment of Non-Melanoma Skin Peri-Auricular Cancers—A Retrospective Analysis of a Single Institution Experience

“…Another solution is to use individual applicators attached to a thermoplastic mask [ 28 ]. The application of this method provides, with small and irregular changes, a more conformal dose distribution than electron brachytherapy with high treatment efficacy [ 29 ].…”

The value of brachytherapy in the age of advanced external beam radiotherapy: a review of the literature in terms of dosimetry

“…Six studies have been published on the dosimetric comparison of surface mould HDR-BT and VMAT for the treatment of skin lesions on the scalp and the extremities [62][63][64][65][66][67]. Boman et al [63] used four and three plans of patients treated with HDR-BT surface mould on the scalp and lower leg, respectively, and retrospectively created VMAT plans with the PTV created on the CTV of BT plans with an additional 3-mm setup margin.…”