Timing or criteria to trigger adaptive radiotherapy (ART) for nasopharyngeal carcinoma (NPC): A systematic review

Abstract

Introduction

Nasopharyngeal carcinoma (NPC), prevalent in Southern China and Southeast Asia, is primarily treated with radiation therapy (RT) and concurrent chemoradiotherapy (CCRT). Due to its anatomical complexity and changes during treatment, adaptive radiotherapy (ART) is employed to adjust plans mid-course. However, ART is time-consuming and labor intensive. This systematic review aims to summarize and analyze the timepoints and criteria used to trigger replanning in NPC patients undergoing ART.

Methods

A systematic search was conducted in PubMed and Scopus to identify studies reporting on the timing or criteria for replanning in NPC patients treated with ART. Eligible studies were screened, and relevant data were extracted.

Results

51 studies met the inclusion criteria. Among these, 42 recommended a single replanning session, 3 suggested one or two sessions depending on individual factors, 4 proposed two sessions, and 2 recommended three. Week 5 was the most frequently reported timepoint for initiating ART, followed by weeks 4 and 3. Tumor volume reduction was a common criterion. Changes in parotid gland anatomy and dosimetric parameters were frequently cited due to their relevance as organs at risk. Body weight loss was a triggering factor in eleven studies, while four studies highlighted ill-fitted masks as indicators for ART initiation.

Conclusion

There is notable variability in the timing or criteria for initiating ART in NPC patients. Prospective studies are necessary to develop evidence-based ART guidelines and protocols.