IMPROVEMENT OF RADIATION TREATMENT PLANNING IN SQUAMOUS-CELL HEAD ANDNECK-CANCER BY IMMUNO-SPECT

Previous studies have shown high accuracy for immunoscintigraphy with Tc-99m-MAb-174 in patients with squamous-cell carcinoma of the head an d neck region compared to CT and MRI. We conducted a prospective study to determine if immunoscintigraphy provides additional diagnostic inf ormation for radiation treatment planning, Methods: Radioimmunoscintig raphy (RIS) was performed on 40 patients (planar, whole-body, SPECT) w ith histologically confirmed squamous-cell carcinoma (30 primary tumor s, 10 recurrences) after injection of the Tc-99m (1.1 GBq) labeled mon oclonal anti-squamous-cell cancer antibody 174H0.64 (murine IgG1). Res ults were combined with information obtained by clinical examination, sonography, panendoscopy and x-ray CT. The strategy for radiation trea tment and the required treatment volumes were defined with and without immunoscintigraphical findings. Results: Additional diagnostically re levant information from RIS was obtained from 10 patients (25%) with a dvanced tumors or recurrences. In three patients (7.5%), the treatment volume had to be extended, The therapeutic strategy for seven patient s (17.5%) had to be changed due to the detection of metastatic disease beyond the head and neck region. RIS of patients with squamous-cell c ancers of the head and neck region with Tc-99m MAb-174H0.64 enabled th e detection of tumors that were not depicted by other conventional dia gnostic imaging procedures. Conclusion: The use of RIS in radiation tr eatment planning of advanced tumors of the head and neck region appear s lo yield important diagnostic information that may alter patient man agement.