Control of nodal metastases in squamous cell head and neck cancer treated by radiation therapy or chemoradiation

Background and purpose: In the present study, prognostic values of several CT-based pre-treatment nodal and treatment-related characteristics were evaluated among patients with squamous cell head and neck cancer treated with non-surgical modalities. Patients and methods: Included were 79 patients with 210 pathological nodes, who underwent primary irradiation or chemoradiation. Several nodal characteristics were assessed on the planning CT scan. In addition, the 3D-dose distribution in the nodes was calculated by the planning system to allow for evaluation of underdosage in the pathological nodes and to correlate these results with control in the neck. Analysis was done on patient level (regional control) and node level (nodal control). Results: For regional control, total nodal volume and the use of chemotherapy in addition to radiation were significant prognostic factors. For nodal control, also the presence of central necrosis and radiological extranodal spread were of importance. In case of radiotherapy alone, a minimal dose <95% of the prescribed dose was associated with worse control. In case of combined modality treatment, the minimal radiation dose was of less importance. Conclusions: Nodal volume and chemotherapy are the most important prognostic factors to control pathological nodes in the neck. Radiological central necrosis and extranodal growth, nodal volume and chemotherapy were significant prognostic factors for nodal control. Additionally, it appears that regional control in patients treated with primary radiation alone or with chemoradiation in case of a total nodal volume of more than 3.0 cm3 results in an unacceptable high risk on regional recurrence