Background: A negative sentinel node biopsy (SNB) implies a good prognosis for melanoma patients. The purpose of this study was to determine the long-term outcome for melanoma patients with a negative SNB.
Methods: Survival and prognostic factors were analyzed for 836 SNB-negative patients. All patients with a node field recurrence were reviewed, and sentinel node (SN) tissue was reexamined.
Results: The median tumor thickness was 1.7 mm, and 23.8% were ulcerated. The median follow-up was 42.1 months. Melanoma specific survival at 5 years was 90%, compared with 56% for SN-positive patients (P < .001). On multivariate analysis, only thickness and ulceration retained significance for disease-free and disease-specific survival. Five-year survival for patients with nonulcerated lesions was 94% vs. 78% with ulceration. Eighty-three patients (9.9%) had a recurrence. Twenty-seven patients developed recurrence in the regional node field, and in 22 of these, it was the first recurrence site. Six developed local recurrence, 17 an in-transit metastasis, and 58 distant disease. The false-negative rate was 13.2%. SN slides and tissue blocks were further examined in 18 patients with recurrence in the node field, and metastatic disease was found in 3 of them.
Conclusions: This large, single-center study confirms that patients with a negative SNB have a significantly better prognosis than those with positive SNs. In those with a negative SNB, primary tumor thickness and ulceration are independent predictors of survival. Incorrect pathologic diagnosis contributed to only a minority of the false-negative results in this study.