Optimizing intensity-modulated radiation therapy for stage II nasopharyngeal cancer: A comparative study of 7-field and 9-field treatment plans

Abstract

This study aims to compare the efficacy of 7-field and 9-field intensity-modulated radiation therapy (IMRT) configurations in the treatment of stage II nasopharyngeal cancer (NPC) to determine the optimal approach for maximizing tumor coverage and minimizing radiation exposure to critical organs. Twenty-one patients with stage II NPC were treated using the Elekta Synergy Platform linear accelerator and the Monaco treatment planning system. Two IMRT configurations, 7-field and 9-field, were evaluated for their dose distributions to target volumes (PTV70, PTV60, and PTV54) and sparing of critical organs (spinal cord, brainstem, parotid glands, and optic structures). Dose-volume histograms (DVHs) were used to assess plan quality. The 9-field IMRT technique demonstrated superior dose coverage for target volumes and better sparing of critical organs compared to the 7-field technique. Specifically, the 9-field configuration achieved higher mean percentages of volume receiving the prescribed dose for PTV70, PTV60, and PTV54. Moreover, the 9-field technique resulted in lower mean doses to critical organs, including the spinal cord and parotid glands, while maintaining doses within clinically acceptable limits. The 9-field IMRT technique offers significant advantages in terms of tumor coverage and critical organ protection for stage II NPC patients. Despite the increased complexity and treatment time, the enhanced therapeutic efficacy and safety profile make the 9-field IMRT configuration the preferred choice for optimizing radiotherapy outcomes in NPC treatment.