Patterns of recurrence following a negative sentinel lymph node biopsy in 243 patients with stage I or II melanoma.

PURPOSE: To determine the patterns of recurrence and causes of regional nodal basin failure in stage I or II melanoma patients who had a histologically negative sentinel lymph node (SLN) and whose regional nodal basins were not dissected following lymphatic mapping and SLN biopsy.

PATIENTS AND METHODS: The records of 344 patients with primary cutaneous melanoma who underwent lymphatic mapping and SLN biopsy between 1991 and 1995 at The University of Texas M.D. Anderson Cancer Center were reviewed. Of 322 patients who underwent successful lymphatic mapping procedures, 270 had histologically negative SLNs; mapped nodal basins were observed without further surgical intervention in 243 of these 270 patients. Recurrence patterns were analyzed from this cohort and a histologic reevaluation of all previously identified SLNs on which a biopsy had been taken was performed in patients who developed recurrent disease.

RESULTS: Of 243 patients with a histologically negative SLN, 27 (11%) developed local, in-transit, regional nodal, and/or distant metastases after a median follow-up time of 35 months. Ten patients (4.1%) developed a nodal recurrence in the previously mapped basin, either solely or as a component of the first site of recurrence. Detailed analysis of the SLNs in these 10 patients demonstrated evidence of occult metastases in 80% by serial sectioning or immunohistochemical staining.

CONCLUSION: Regional nodal failures in melanoma patients following a negative SLN biopsy are infrequent and to date have most commonly occurred because conventional histologic evaluation was unable to identify occult metastatic disease. These data provide further evidence that lymphatic mapping and SLN biopsy accurately reflect the status of the regional nodal basin. Specialized pathologic techniques are necessary to reduce further the already low false-negative rates and to improve disease staging.