Commentary on feliciani Giacomo et al.’s study of comparison of HDR-brachytherapy and tomotherapy for the treatment of non-melanoma skin cancers of the head and neck

We deeply appreciate and highly value the work of Feliciani G. et al. entitled “Comparison of HDR-brachytherapy and tomotherapy for the treatment of non-melanoma skin cancers of the head and neck,” which provides significant insights into a highly debated and clinically relevant topic of considerable importance in both clinical practice and research [1]. The comparison between interventional radiotherapy (IRT – brachytherapy) and external beam radiotherapy techniques, has been extensively studied, often yielding different results in terms of target coverage and dose to organs at risk (OARs) [2]. We found your focused analysis of using HDR-IRT in the postoperative setting for eyelids non-melanoma skin cancer particularly insightful, as this represents a challenging clinical scenario due to both biological and anatomical complexities [3]. Nevertheless, we would like to highlight two areas that we believe deserve further discussion and consideration: a) Approach with Interstitial Implants: While the authors compared contact HDR-IRT to tomotherapy it is worth noting that much of the existing evidence on IRT for eyelid NMSC lesions relies on interstitial implants; this type of approach is certainly more complex to perform in the procedural phase but allows for relevant dosimetric advantages such as a more tailored dose coverage of the thickness of the lesion, the chance to deliver a higher BED10 and the possibility to reduce excessive dose to OARs [4]. b) Impact of Bolus Use on Dosimetry: In the results section the authors state that “HT provided more consistent target coverage than HDR-BT, with a statistically significant difference”. While we agree with the use of the TG-186 for the dose calculation as suggested by the researchers since eyelid tumors are usually characterized by small clinical target volumes strictly adjacent to sensitive OARs (ocular structures), there is evidence that in this specific setting the use of bolus could modify both the CTV coverage and the dose to OARs in a clinically relevant way and we feel that this addition should be shared with the readers of this article [5]. Our comments, building on the groundwork laid by this paper, aim to provide readers with comprehensive clinical and dosimetric tools to advance understanding and practice in this important area. These tools focus on the use of HDR- IRT for treating NMSC lesions on the face, particularly around the eyelids, offering a conservative alternative to potentially disfiguring surgical approaches.