[Oral cavity and pharyngo-laryngeal squamous cell carcinoma. What lymph node volumes to select for external beam radiation therapy?]

The selection of target volumes for head and neck cancer radiation therapy, particularly prophylactic volumes that reflect infra-clinic spreads, is a complex process. It is based on the knowledge of the natural history of these tumors and must take into consideration the special challenges due to the diversity and complexity of head and neck anatomy. The dosimetric and ballistic precision provided by modern radiation techniques has required strong strategic deliberation to ensure the relevance and reproducibility of target volumes. Specifically, regarding cervical lymph node volumes, two issues emerged. What lymph node area to select depending on the location and the staging of the primary tumor? How to convey that choice in the process of treatment planning and delivery? This debate has been progressively enriched over time resulting in the publication of several international guidelines to standardize the terminology of head and neck lymph node areas and to lay solid science-based foundations to drive practices. This abundance of information makes these guidelines complex, but their accurate understanding is required for adequate usage. We provide an overview of the main published recommendations for the selection of lymph node target volumes when treating oral cavity and pharyngo-laryngeal squamous cell carcinoma with radiation therapy.