Adaptive radiotherapy for head and neck cancer: practical clinical benefits and future perspectives

Abstract

Background: Head and neck cancer (HNC) HNC is typically diagnosed in a locally advanced yet potentially curable stage, for which radiotherapy (RT), either alone or in combination with concurrent chemotherapy, is usually the main treatment of choice. The technological advancement in RT technology, including intensity-modulated radiation therapy (IMRT), Volumetric modulated arc therapy (VMAT), and image-guided radiation therapy (IGRT), yield precise delivery of radiation beams to the target and better sparing of normal tissues. Patients with HNC often experience anatomical changes during RT, which may result in unintended dosimetric shifting affecting the side effect profile and potentially the efficacy of the treatment. The small deviations from geometric data might greatly change the dose distribution in target volume and organ at risk from what is planned. During the RT of HNC, the parotid, minor salivary glands, submandibular, pharynx, larynx, spinal cord, and brain stem often exposed with substantial doses of radiation. Radiation-induced xerostomia is usually triggered by quantitative and qualitative changes in the salivary glands.

Aim: The aim of the study is to assess the real benefit of adaptive radiotherapy (ART) during the treatment in HNC, and also reveal the precise criterias to patient selection, optimal number and timing of re-planning, and convenient approaches to image registration and dose calculation.

Methods: Several case reports which were published over the period of last 18 years were studied analyzed. We performed an electronic review of articles published in PubMed/MEDLINE and authorized medical journal from January 2006 to December 2024. Our study was including to numerous articles Based on high reliability sources worldwide clinical and literary experience dealing with locally advanced HNC and anatomical/dosimetric variation in the context of ART.

Results:Numerous randomized prospective and retrospective trials have shown that adaptive radiotherapy (ART) in HNC demonstrates improved target coverage and reduction in doses to critical structures and suggests improved local control and reduced toxicity. Artificial Intelligence (AI) software program to facilitate radiotherapy replanning is a promising solution to improve treatment accuracy and efficiency and potentially improve the therapeutic ratio. Despite the large evidence-based information data, the diverse strategies of ART in HNC remain controversial, as well as the documented dosimetric and clinical advantages associated with these modalities.   

Conclusions: The accumulated information from many reliable studies and ongoing retrospective studies give hopes, that in the future, it will be possible to determine the exact criteria for conducting adaptive radiotherapy, such as correct patient selection. The ideal frequency and timing of re-planning and convenient approaches of dose-volume calculation and advanced technological modalities of image registration modes.