Individualized Clinical Target Volume Delineation in Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma arises from the mucosa lining the nasopharynx. Although it is relatively uncommon worldwide, high incidence rates are observed in east and southeast Asia, North Africa, and the Middle East (Chang et al. 2021; Chen et al. 2019). Unlike other head and neck cancers, nasopharyngeal carcinoma tends to affect younger populations, peaking at approximately age 45–59 in high-risk populations (Chang et al. 2021). Radiation therapy remains the mainstay of treatment in these patients, resulting in excellent outcomes. Given the young ages of these patients at diagnosis and the high rates of tumor control, these patients are at risk for long-term toxicities from radiation therapy including xerostomia, swallowing dysfunction, endocrinopathies, cranial nerve deficits, hearing loss, and radiation necrosis. As such, it is imperative to consider how treatment outcomes can be improved in these patients. Delineation and coverage of microscopic disease within the clinical target volume (CTV) are crucial in head and neck radiation treatment planning. In this chapter, we discuss efforts to more accurately delineate target volumes in nasopharyngeal carcinoma.