Biblioteca Virtual en Salud

Most first relapses in patients with melanoma occur in regional lymph nodes basins. Such lesions are frequently diagnosed clinically during the first 2 y of follow-up. In the las few years, our group has been studying the usefulness of 99Tc-methoxy-isobutylisonitrile (MIBI) scintigraphy in the evaluation of recurrent melanoma lesions. The aim of the present study was to prospectively evaluate the clinical value of 99mTc-MIBI scintigraphy in the diagnosis of subclinical nodal metastases. Methods. We icnluded 66 patients within 3 mo of melanoma diagnosis, with Breslow thickness >1.0mm, all treated with wide local excision ofthe primary lesion. When 99mTc-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-fiel-of-view gamma camera equipped with a low-energy high-resolution collimator. Scan findings were confirmed by pathology of 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 the were initially 99mTc-MIBI negative, nodal metastases were found during follow-up. The following diagnostic values were calculated sensitivity, 0.91 (95 percent confidence interval CI, 0.75-0.98); specificity, 0.85 (95 percent CI0.67-0.94); likelyhood ratio of a positive test 6.0 (95 percent CI 2.7-13.5); and likelyhood ratio of a negative test, 0.11 )95 percent CI 0.036-0.32).

Conclusion:

99mTc-MIBI scanning may have a secondary role in the staging of regional lymph nodes in patients clinically localized melanoma who are not good candidates for sentinel node biopsy