Lymphoscintigraphy in tumors of the head and neck using double tracer technique

Knowledge of possible lymphatic drainage may facilitate planning of surgery for patients with head and neck tumors. Therefore, the aim of this study was to present a method of lymphoscintigraphy with special attention to an accurate correlation of lymphatic drainage to anatomic regions.

Lymphoscintigraphy was performed using a double tracer technique before surgery in a total of 75 patients with squamous cell carcinoma of the head and neck. All patients received 100 MBq 99mTc-colloid at three to four peritumoral sites. A perchlorate solution (2 mL) was given orally to block salivary glands and the thyroid gland. Patients received 50 MBq 99mTc-pertechnetate intravenously for body contouring 20 min postinjection. Planar images were obtained over 5 min each, at 30 min and 4 h postinjection from anterior, right lateral and left lateral views with a large-field-of-view gamma camera. Lymphatic drainage was assessed by visual inspection and assigned to six cervical compartments.

Neither the salivary glands nor the thyroid gland were seen in any of the patients. In 22 of 75 patients (29.3%), the injection site was the only focal tracer uptake seen. In contrast, lymphatic drainage was identified in the remaining 53 patients (70.7%), and lymph nodes could be assigned easily to the six cervical compartments. Of 75 patients, 36 (48%) exhibited ipsilateral lymphatic drainage. In addition, 17 patients (22.7%) with unilateral tumor showed bilateral (n = 12), contralateral (n = 2) or retropharyngeal (n = 3) lymphatic drainage. In 3 of these 17 patients, bilateral lymph node metastases were proven. A subgroup of 12 patients (16%) exhibited N2c nodal status, despite a unilateral localized primary tumor. In 3 of these 12 patients, surgery was extended as a result of scintigraphic findings from unilateral toward bilateral neck dissection, and histology confirmed nodal involvement in these patients.

Lymphoscintigraphy using the double tracer technique allows an accurate correlation of lymphatic drainage to the six cervical compartments. This may provide the basis for a re-evaluation of its impact in treatment planning of patients with head and neck tumors.