Prevention of critical weight loss. In patients with Squamous Cell Carcinoma of the Head and Neck (SCCHN) weight loss is a relevant clinical problem during radiotherapy and might result in higher treatment related toxicity and discontinuation of a potential curative treatment. Thus the investigators want to evaluate the efficacy of overnight parenteral nutritional (PN) support in patients with SCCHN treated with curative radiotherapy (RTX) in combination with Cetuximab (E) or Cisplatin (P).