Patterns of first-recurrence and post-recurrence survival in patients with primary cutaneous melanoma after sentinel lymph node biopsy

Background: Sentinel lymph node biopsy (SLNB) has become well accepted in management of patients with primary cutaneous melanoma. An understanding of the pattern of recurrence after SLNB is helpful in coordinating a rational plan of follow-up in these patients. We sought to determine the site and timing of initial recurrence and post-recurrence survival after SLNB. Methods: Stage I/II melanoma patients who underwent SLNB during 1991-2004 were identified from a prospective single-institution database. Site and date of first recurrence after SLNB were recorded. Patterns of recurrence after SLNB and post-recurrence survival were analyzed. Results: One thousand and forty-six patients underwent SLNB. The sentinel lymph node (SLN) was positive in 164 patients (16%). Median follow-up was 36 months for survivors. Median and 3-year relapse-free survival for SLN-positive patients were 41 months and 56%, and for SLN-negative patients were not reached and 87%, respectively (P < .0001). Of the SLN-positive patients, 47% experienced recurrence, compared with 14% SLN-negative patients. The pattern of recurrence stratified by SLN status was similar between the two groups (P = NS). After recurrence, the site of recurrence was the only significant prognostic factor influencing survival (P < .0001). Conclusions: Although SLN-positive patients experience recurrence far earlier and more frequently than SLN-negative patients, the pattern of recurrence is similar. After recurrence, its site is the primary determinant of survival.