Radiation therapy on primary tumour of synchronous metastatic head and neck squamous cell carcinomas

Purpose: Patients with synchronous metastatic head and neck squamous cell carcinomas often present associated locoregional symptoms and a risk of life-threatening primary tumour progression. Few data have been published about the use of radiation therapy in the management of newly diagnosed metastatic disease associated with advanced locoregional disease. In this article, we aim to determine the role of radiation therapy of the primary tumour in the overall therapeutic strategy for these diseases. We further address radiation therapy modalities (technique, volumes, and fractionation) in such a context.

Material and methods: We conducted a literature survey on locoregional radiotherapy for newly diagnosed metastatic head and neck squamous cell carcinomas.

Results: Several retrospective studies have reported that locoregional radiotherapy is associated with improved overall survival of patients with synchronous metastatic head and neck squamous cell carcinomas. However, data about modalities such as timing of radiotherapy in the overall strategy, dose, fractionation and delineation volumes are scarce. Two schematic situations can be distinguished with respect to prognosis and treatment adaptations: polymetastatic/bulky or oligometastatic disease. In polymetastic/bulky disease associated with poor prognosis, standard-of-care is systemic therapy, but locoregional radiotherapy can be discussed either upfront, mainly for symptomatic palliation, or as consolidation after downsizing obtained by systemic therapy. As for oligometastatic disease, with the rise in use of efficacious and well-tolerated local ablative treatments of metastases, aggressive curative-intent locoregional radiotherapy can be considered with or without systemic therapy.

Conclusion: Because locoregional disease is a major cause of disease failure in patients with synchronous metastatic head and neck squamous cell carcinomas, aggressive locoregional radiation therapy to the primary tumour may be discussed in the initial management of the disease where systemic therapy alone may not induce sufficient primary tumour reduction. With recent technological advances in radiotherapy, the delivery of radiotherapy is safe and feasible even in metastatic setting. Clinical trials assessing radiotherapy use for metastatic head and neck squamous cell carcinomas are warranted.