Abstract: In metastatic or locally advanced head and neck tumors that present in frail patients or after chemotherapy progression, radiotherapy is normally used as a palliative treatment, with a high rate of symptom palliation and improvement in quality of life. However, there is controversy about what the optimal regimen is. Moreover, despite the poor prognosis of metastatic head and neck cancer, different retrospective studies have shown that a minority of patients with oligometastatic disease experience prolonged disease-free survival after adding curative radiotherapy treatment to the metastatic disease and/or primary tumor. Different retrospective studies have identified clinical prognostic factors that may be used to select candidate patients with metastatic head and neck cancer for a radical approach with radiotherapy. The purpose of this manuscript is to review the role of radiotherapy in metastatic and locally advanced head and neck tumors.
Keywords: palliative, head and neck cancer, radiotherapy, oligometastatic disease
Head and neck cancer (HNC) has a predominant locoregional pattern of recurrence, with local and/or regional recurrence rates of 45%–50% and incidence of distant metastasis (DM) <20%.1 However, in cases with advanced lymphatic cervical disease, such as N3 cases or when lower cervical nodes are affected, DM incidence may rise to approximately 30%.2 Cetuximab has been shown to prolong overall survival (OS) in patients with advanced or metastatic HNC (mHNC) who have received chemotherapy (from 7.4 months to 10.1 months, P=0.04) and is actually considered the first line palliative systemic treatment in this disease.3 On the other hand, radiotherapy (RT) has been used as palliative treatment in this clinical setting, with a high rate of symptom palliation and improvement in quality of life for patients presenting progression after chemotherapy or in frail patients who are not candidates for chemotherapy.4
Despite the poor prognosis of mHNC, different retrospective studies have shown that a minority of patients with oligometastatic disease experience prolonged disease-free survival after the addition of curative RT treatment to the metastatic disease and/or primary tumor. Moreover, technological and clinical advances achieved in the field of RT have improved the balance between tumor control and effects on normal tissue, increasing the therapeutic ratio.5 As a result, indications for RT have expanded in recent years to include patients that would not have been treated a few years ago. The purpose of this manuscript is to review the role of RT in patients with mHNC, and to study the prognostic factors that should be identified to select patients with mHNC who are suitable candidates for a more radical approach.
A search for the published results of stereotactic body RT or external RT for mHNC was carried out using Medline, Embase, and Ovid Online via the Athens website. Terms searched for (all fields) were “stereotactic radiosurgery”, “stereotactic body radiotherapy”, “stereotactic body radiation therapy”, “head and neck neoplasm”, “metastases”, and “oligometastases”. Appropriate manuscripts were selected from the lists generated, and additional papers found through a manual search of the references contained in these publications were added. The period of inclusion was 2007–2018.