De-Intensification of Postoperative Radiotherapy in Patients With Squamous Cell Carcinoma of the Head and Neck

Inclusion Criteria: 1. Histologically proven squamous cell carcinoma of the oral cavity/larynx/oro-or hypopharynx (except glottis cancer (pT1/2pN0)) 2. Surgery of primary tumor and neck dissection performed according to predefined surgical standard 3. Indication for postoperative radio(chemo)therapy 4. No lymph node metastases \> 6cm 5. Lymph node metastases in not more than 3 lymph node level 6. No distant metastases (cM0) 7. Age ≥ 18 years, no upper age limit 8. Eastern Cooperative Oncology Group (ECOG) ≤ 2 9. Patients who understood protocol contents and are able to behave according to protocol 10. Signed study-specific consent form prior to therapy 11. Start of radiotherapy at least 6 weeks after last tumor-specific surgery (e.g. resection primary tumor, neck dissection, excluded are surgeries according to wound healing complications) Exclusion Criteria: 1. macroscopic incomplete resection R2 2. Distant metastases (cM1) 3. Radiologically or histologically proven early recurrence after surgery (time frame from surgery to start of radio(chemo)therapy) 4. Lymph node metastases in \> 3 lymph node level 5. pregnant or lactating/nursing women 6. fertile patients that are not willing to use highly effective methods of contraception (per institutional standards) during treatment 7. Any condition potentially hampering compliance with the study protocol and follow-up schedule 8. On-treatment participation on other clinical therapeutic trials 9. Prior tumor-specific therapy any other than surgery (like prior radiotherapy in the head and neck region, prior chemo- or immunotherapy (neoadjuvant/induction)) 10. Patients who have contraindication for MRI and CT with contrast agent (both) 11. Prior (\> 2 months before beginning of radio(chemo)therapy) neck dissection or surgery in the head and neck area affecting lymph drainage 12. History of another primary malignancy except for malignancy treated with curative intent and with no known active disease ≥5 years before diagnosis of head and neck cancer, adequately treated non-melanoma skin cancer or lentigo maligna without evidence of disease, adequately treated carcinoma in situ without evidence of disease