COMBINED TREATMENT OF ADVANCED OROPHARYNGEAL CANCER WITH EXTERNAL RADIOTHERAPY AND 3-STEP RADIOIMMUNOTHERAPY

The prognosis of patients with locally advanced head and neck cancer r emains grim due to poor locoregional tumour control. In the attempt to eradicate residual disease, various novel modalities have been tested , among which radioimmunotherapy (RIT) has shown some potential. We pr esent a case of locally advanced oropharyngeal carcinoma successfully treated with a combination of various treatments including surgery, ra dio-chemotherapy and three-step RIT, with the avidin-biotin pretargeti ng system. A partial tumour response was achieved after surgery and ra dio-chemotherapy; persistent disease was documented at computed tomogr aphy (CT), ultrasound (US) and immunoscintigraphy (ISG) 10 weeks after the end of chemo-radiotherapy. The good correlation between the trace r localization in the scintigraphic images and residual mass visualize d at CT suggested the application of three-step RIT using systemic adm inistration of yttrium-90 (py) biotin. At present, 17 months after RIT , the patient is alive with no evidence of disease as documented by ma gnetic resonance imaging (MRI) and US. This is the first case of compl ete clinical remission of a head and neck carcinoma induced by combine d treatment including pretargeted RIT with Y-90-biotin.