Staging of regional lymph nodes in melanoma patients by means of 99mTc-MIBI scintigraphy.
Most first relapses in patients with melanoma occur in regional lymph node basins. Such lesions are frequently diagnosed clinically during the first 2 y of follow-up. In the last few years, our group has been studying the usefulness of (99m)Tc-methoxyisobutylisonitrile (MIBI) scintigraphy in the evaluation of recurrent melanoma lesions. The aim of the present study was to prospectively evaluate the clinical value of (99m)Tc-MIBI scintigraphy in the diagnosis of subclinical nodal metastases.


METHODS
We included 66 patients within 3 mo of melanoma diagnosis, with Breslow thickness > 1.0 mm, all treated with wide local excision of the primary lesion. When (99m)Tc-MIBI scanning was performed, 49 of them did not have evidence of nodal disease, and 17 had clinically questionable regional lymph node lesions. Planar images of lymph node regions were acquired 10 min after injection, using a dose of 740-1,110 MBq and a large-field-of-view gamma camera equipped with a low-energy high-resolution collimator. Scan findings were confirmed by pathology or by clinical follow-up (median, 35 mo).


RESULTS
Thirty of 33 patients with regional lymph node metastases received a correct diagnosis, 14 with palpable lesions and 16 with nonpalpable lesions. In 3 cases that were initially (99m)Tc-MIBI negative, nodal metastases were found during follow-up. The following diagnostic values were calculated: sensitivity, 0.91 (95% confidence interval [CI], 0.75-0.98); specificity, 0.85 (95% CI, 0.67-0.94); likelihood ratio of a positive test, 6.0 (95% CI, 2.7-13.5); and likelihood ratio of a negative test, 0.11 (95% CI, 0.036-0.32).


CONCLUSIONS
(99m)Tc-MIBI scanning may have a secondary role in the staging of regional lymph nodes in patients with clinically localized melanoma who are not good candidates for sentinel node biopsy.
Alonso
Omar
O
Nuclear Medicine Center, Clinical Hospital, University of Uruguay, Montevideo, Uruguay. oalonso@hc.edu.uy
Martínez
Miguel
M
Delgado
Lucía
L
De León
Ana
A
De Boni
Daniela
D
Lago
Graciela
G
Garcés
Mariela
M
Fontes
Flávia
F
Espasandín
José
J
Priario
Julio
J
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D008545:Melanoma / Q000000981:diagnostic imaging* / Q000473:pathology / Q000556:secondary*; D008875:Middle Aged; D009367:Neoplasm Staging / Q000379:methods*; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016037:Single-Blind Method; D012878:Skin Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D017256:Technetium Tc 99m Sestamibi
D019275:Radiopharmaceuticals; D017256:Technetium Tc 99m Sestamibi