Clinical imaging of head and neck cancer with technetium-99m-labeled monoclonal antibody E48 IgG or F(ab')2

Methods: In 32 patients who were suspected of having a neck lymph node metastasis from a histologically proven squamous-cell carcinoma of the head and neck (HNSCC), the diagnostic value of 99mTc-labeled (750 MBq) monoclonal antibody (1-2 mg) E48 IgG (n = 17) and its F(ab')2 fragment (n = 15) was evaluated and compared. Preoperative findings on lymph node status obtained by radioimmunoscintigraphy (RIS), computerized tomography (CT), magnetic resonance imaging (MRI) and palpation were defined per side (left and/or right side of the neck) as well as per lymph node level (I through V) and compared to the histopathological outcome of the neck dissection specimen. Results: All 31 tumors at the primary site were visualized. RIS was correct in 201 of 221 levels (accuracy 91%) and in 38 of 47 sides (accuracy 81%). Fifteen levels and seven sides with limited tumor load were scored false-negative and five levels and two sides were scored false-positive. Sensitivity and specificity of RIS were similar to those of palpation, CT and MRI. The diagnostic value of RIS with E48 F(ab')2 or E48 IgG appeared to be similar. Conclusions: The present study shows that RIS with either E48 F(ab')2 or E48 IgG is as valuable as the other imaging techniques. The selective accumulation of radioactivity in tumor tissues, in combination with the known intrinsic radiosensitivity of HNSCC, justifies the development of radioimmunoconjugates for radioimmunotherapy