Microscopic satellitosis in patients with primary cutaneous melanoma: implications for nodal basin staging

Microscopic satellitosis in melanoma is uncommon. The role of regional basin staging/therapy in patients with this high-risk feature has not been well defined.

Patients presenting from 1996 to 2005 with clinically localized melanoma containing microscopic satellitosis were identified from a prospective, single-institution database. Multiple factors were analyzed to determine their predictive value for recurrence. The management of the draining nodal basin was evaluated to determine its impact on recurrence and survival.

Thirty-eight patients presented to our institution during this time period with clinically localized melanoma containing microscopic satellitosis. The 5-year overall and disease-free survivals in these patients were 34% and 18%, respectively. Sixty-eight percent had pathologically involved regional nodal metastases. With median follow-up of 21 months, 68% recurred, with a median time to recurrence of 9 months. Lymphovascular invasion (LVI) (p = 0.01), tumor regression (p = 0.04), and positive regional lymph nodes (p = 0.02) were associated with an increased risk of recurrence. Of the 31 patients who underwent sentinel lymph node (SLN) biopsy, 22 had metastasis in the SLN (71%). Fifteen of these patients underwent completion lymphadenectomy (CLND) and seven were observed. There was no difference in disease-free survival (DFS), disease-specific survival (DSS), or overall survival (OS) between these groups (p = 0.42).

Pathological lymph node metastases were more prevalent (68%) than in any group previously defined. Regional nodal status predicted recurrence but not nodal recurrence. In SLN-positive patients, CLND did not improve DFS, DSS, or OS, although the number of patients was small. Further studies are needed to determine the utility of regional nodal staging/therapy in these high-risk patients.