Background/Hypothesis: We hypothesize that the progression of disease from the sentinel lymph node (SLN) to the non-SLN compartment is orderly and is associated with the worsening of the disease status. Thus, the sentinel and non-sentinel lymph node compartments are biologically different in that cancer cells, in general, arrive in the sentinel lymph node compartment before spreading to the non-sentinel lymph node compartment. To validate this concept, we use a large cohort of melanoma patients from our prospective SLN database.
Design: Retrospective analysis of a prospective melanoma database.
Setting: Academic tertiary medical center.
Patients: Adult cutaneous melanoma (CM) patients (n=291) undergoing CLND after a positive SLN result from 1994 to 2009.
Interventions: Wide local excision and SLN biopsy, followed by CLND.
Main Outcome: Comparison of 5-year disease-free survival and 5-year overall survival between positive and negative CLND groups.
Results: 225 patients had negative CLND and 66 had positive CLND (22.7%). The 5-year disease-free survival rates were 55% (95% CI: 49% - 62%) for patients with no additional LN on CLND versus 14% (95% CI: 8% - 26%) in patients with positive LN on CLND (p<0.0001, log-rank test). The median disease-free survival time was 7.4 years with CLND negative (95% CI: 4.4 to 15+ years) and 1.2 years with CLND positive (95% CI: 1.0 to 1.8 years).
The 5-year overall survival rates were 67% (95% CI: 61% - 74%) for negative CLND versus 38% (95% CI: 28% - 52%) for positive CLND (p<0.0001, log-rank test). The median overall survival time was 12.1 years for CLND negative (95% CI: 9.3 to 15+ years) and 2.5 years for CLND positive (95% CI: 2.2 to 5.7 years).
Conclusion: This study shows that CLND status is a significant prognostic factor for patients with positive SLNs undergoing CLND. In patients, when the non-SLN compartment is not involved with metastasis, their survival is much improved. Thus, information from CLND is important to predict the outcome of melanoma patients with a positive SLN biopsy.