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Nucl Med Commun, 20: 919-924,1998. ROLE OF LYMPHOSCINTIGRAPHY AND INTRAOPERATIVE GAMMA PROBE GUIDED SENTINEL NODE BIOPSY IN HEAD AND NECK MELANOMAS M Maccauro", F Gallino 2 , G Aliberti', G Savelli', MR Oastellani', C Villano'', 8M saio', AET Goilo", F Be1li 2 , L Mansi", and E Bombardier!' JUO Medicina Nucleare, 2Direzione Scientifica, Istituto Nazionale Tu- mori, Milan; 3II Universita degli Studi, Naples, Italy Correspondence to: Dr Marco Maccauro, UO Medicina Nucleare, Istituto Nazionale Tumori, Via Venezian 1,20133 Milano, Italy. E-mail maccau- ro@istitutotumori.mi.it Introduction The progress in the development of diagnostic techniques over the last 20 years has made it possible to identify tumors at an ear- lier stage. In particular, the technique of sentinel node (SLN) de- tection has reduced the need for more invasive procedures of tu- mor staging. The aim of this study was to identify the sentinel lymph node and its complex drainage in patients with melanoma of the head and neck region. We will try to demonstrate that this technique gives the surgeon a choice between elective and total lymph node dissection. Material and methods In this study 41 patients (27 males and 14 females) were eval- uated. All patients had a diagnosis of melanoma of the head or neck without any clinical evidence of lymph node metastases'>, The primary melanoma was located on the scalp in seven patients (17%), on the face in 21 patients (51%), on the ear in eight (20%), and in the neck in five patients (12%) (Table 1). In five patients the melanoma was still present at the time of Iym- phoscintigraphy, while in 36 patients the primary lesion had been removed: The thickness of the lesions was measured in all pa- tients. We used the procedure first described by Morton in 1992 6 . Lymphoscintigraphy was performed one day before surgery to identify the lymphatic basins that could not be recognized solely on the basis of anatomic knowledge. The radiopharmaceutical consisted of albumin particles ranging in size from 5 to 80 nm, labeled with technetium (Nanocolloidj'v. About 40 MBq of 99mTc Nanocoll was injected subcutaneously in the peritumoral region if the tumor was still present or around the scar if the primary' le- sion had been removed. After tracer administration 15-minute dy- namic acquisition followed by static acquisition for five minutes was carried out with a gamma camera (Picker Prism 1000 XP)9-12. A cobalt flood was used to obtain a better anatomic image. Final- ly, to facilitate the resection a reference mark was made with a cobalt? marker. For more precise isolation of the SLN methylene blue was injected just before surgery. Intraoperative identification of the SLN was done with a crystal scintillator NaI (Tl) probe (Navigator, Gamma Guidance System, USSC)13.14. Results It is very difficult to identify SLNs in melanomas of the head and neck as this area is rich in lymph nodes, so the drainage could be directed towards several lymph node stations. Lym- phoscintigraphy showed lymphatic distribution to more than one basin in 24 of our patients. Two basins were identified in 11 pa- tients (26%), three basins in six patients (15%) and four basins in seven patients (17%). In 16 patients only one basin was found and in one patient no basins could be identified (Table 2). The SLN was found in 40 of the 41 patients (98%). Eighty- five percent of the identified lymphatic basins were biopsied. The location of the visualized nodes was 25 submandibular ipsi- lateral to the lesion (31%), 23 laterocervical (29%), 17 parotid (20%),5 preauricular (6%), 4 postauricular (5%), 3 buccal (3%), 2 supraclavicular (2%), 1 maxillary (1%), 1 spinal (1%), 1 sub- mandibular contralateral to the lesion (1%) and in one patient no basins were visualized (l %). Lymph node metastases were found in ten patients (24%); three patients had metastases in more than one basin (30%). All patients with a positive SLN biopsy underwent total lymph node dissection. In seven of these patients the primary lesion had a thickness of = 3 mm, in two patients primary lesion thickness was in the range of 0-1.99 mm, and in one patient it was 2-2.99 mm. No complications occurred during this study and no morbidity was observed during hospi- talization. At the time of the present evaluation it was documented that 35 patients (85%) were still alive, three were dead (7%), one pa- tient had developed distant metastases and was lost to follow-up, and two patients were lost to follow-up after surgery was taken. Of the ten patients who underwent a lymphadenectomy, nine were still alive and six were free of disease. The other three de- veloped distant metastases (liver, lungs, brain and kidney); one of them had abandoned treatment. Patients had a follow-up from 1 to 40 months (median 21 months). In this period 33 of the 35 pa- tients (94%) survived: 31 (94%) were free of disease, one devel- oped distant brain metastases and one had a local recurrence and Table 1 - Scintigraphic sentinel node localization Location of No. Total no. Sub- Latero- Parotid Preauricular Other melanomas patients SLNs mandibular cervical locations Face 21 46 18 10 9 2 7 Scalp 7 19 4 4 6 1 4 Ear 8 10 2 5 2 1 0 Neck 5 7 1 4 0 1 I Total 41 82 25 (31%) 23 (29%) 17(20%) 5 (6%) 12 (14%)