Melanoma recurrence patterns after negative sentinel lymphadenectomy.

HYPOTHESIS

A tumor-negative sentinel node (SN) does not eliminate the chance of melanoma recurrence. Patterns of metastasis can be identified and characterized in patients with tumor-negative SNs.

DESIGN

Retrospective review.

SETTING

Melanoma referral center.

PATIENTS

Patients who underwent lymphatic mapping and sentinel lymphadenectomy between 1995 and 2002 and whose SNs were negative for metastasis by hematoxylin-eosin and immunohistochemistry staining were included in the study. The SN specimens from patients with recurrent disease were reexamined for missed metastasis.

MAIN OUTCOME MEASURES

Differences in survival related to sites of recurrence and the rate of false-negative histopathologic SN diagnosis were determined.

RESULTS

At a median follow-up of 36.7 months, 69 (8.9%) of 773 patients with tumor-negative SNs had recurrent disease. Three-year survival after first recurrence was 17.1% in the 37 patients with distant recurrence, 48.7% in the 19 patients with local or in-transit recurrence, and 63.5% in the 13 patients with regional basin recurrence; the difference in survival between patients with local or regional and distant recurrences was statistically significant (P<.001). Histopathologic reexamination of SNs from the 69 patients identified 9 patients with false-negative SNs; 2 of these had same-basin recurrences.

CONCLUSIONS

The SN is a valuable prognostic indicator because only 8.9% of patients with tumor-negative SNs will develop recurrence. The low incidence (1.7%) of regional basin recurrence in patients with negative SNs supports the accuracy of our current method of lymphatic mapping and sentinel lymphadenectomy to identify occult regional nodal basin metastasis.