Is intra-operative gamma probe detection really necessary for inguinal sentinel lymph node biopsy?
BACKGROUND
Sentinel node (SN) biopsy has changed the surgical treatment of malignant melanoma. The literature has emphasized the importance of gamma probe detection (GPD) of the SN.


OBJECTIVE
Our objective was to evaluate the efficacy of patent blue dye (PBD) and GPD for SN biopsy in different lymphatic basins.


METHODS
Patients with cutaneous malignant melanoma in stages I and II were submitted to biopsy of the SN, identified by PBD and GPD, as part of a research project.


METHODS
Patients were seen at Hospital São Paulo by a multidisciplinary group (Plastic Surgery Tumor Branch, Nuclear Medicine and Pathology).


METHODS
64 patients with localized malignant melanoma were studied. The median age was 46.5 years. The primary tumor was located in the neck, trunk or extremities.


METHODS
Preoperative lymphoscintigraphy, lymphatic mapping with PBD and intraoperative GPD was performed on all patients. The SN was examined by conventional and immunohistochemical staining. If the SN was not found or contained micrometastases, only complete lymphadenectomy was performed.


METHODS
The SN was identified by PBD if it was blue-stained, and by GPD if demonstrated activity five times greater than the adipose tissue of the neighborhood.


RESULTS
Seventy lymphatic basins were explored. Lymphoscintigraphy showed ambiguous drainage in 7 patients. GPD identified the SN in 68 basins (97%) and PBD in 53 (76%). PBD and GPD identified SN in 100% of the inguinal basins. For the remaining basins both techniques were complementary. A metastatic SN was found in 10 basins. Three patients with negative SN had recurrence (median follow-up = 11 months).


CONCLUSIONS
Although both GPD and PBD are useful and complementary, PBD alone identified the SN in 100% of the inguinal lymphatic basins.
Oliveira Filho
R S
RS
Discipline of Plastic Surgery/Tumor branch, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil. rsoff@ig.com.br
Santos
I D
ID
Ferreira
L M
LM
de Almeida
F A
FA
Simões e Silvia Enokihara
M M
MM
Barbieri
A
A
Tovo Filho
R
R
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003911:Dextrans; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D007264:Inguinal Canal; D007432:Intraoperative Period; D008297:Male; D008545:Melanoma / Q000000981:diagnostic imaging* / Q000473:pathology; D008875:Middle Aged; D015609:Organotechnetium Compounds; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D021701:Sentinel Lymph Node Biopsy; D012878:Skin Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology
D003911:Dextrans; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; C034146:technetium Tc 99m dextran