BACKGROUND: Especially elderly and frail patients have a limited ability to compensate for side effects of a radical treatment of head and neck malignancies. Limiting the target volume to the macroscopic disease, without prophylactic nodal irradiation, might present a feasible approach for these patients. The present work therefore aims evaluating an IMRT/IGRT -SIB concept for safety and efficacy. METHODS: The study retrospectively enrolled 27 patients with head and neck cancers treated between 01/2012 and 05/2015. We evaluated patient files for clinical status, concomitant diseases, treatment side, and treatment volumes as well as for side effects and tumor responses. To describe efficacy and risk factors for worse outcome and higher grade toxicities, we performed cox regression analysis as well as Kaplan-Meier survival time analysis. RESULTS: Median survival was 181 days, 75 % patients showed an early local response at six weeks of follow up. Most patients developed mild to moderate acute toxicities, only one patient with grade IV mucositis was seen. The grade of toxicities was correlated to the size of the PTV. Concomitant diseases, metastatic disease, and G3 Grading were indicators for worse prognosis. CONCLUSION: The IMRT/IGRT SIB concept is a safe and feasible radiotherapy concept for patients not able or not willing to undergo radical treatment.