Less false-negative sentinel node procedures in melanoma patients with experience and proper collaboration.

BACKGROUND AND OBJECTIVES: The aims of the study were to determine the percentage of false-negative sentinel node procedures in melanoma patients, to investigate the time cohort of these recurrences, whether a learning phase was involved and to search for causes of the failures.
METHODS: Between December 1993 and December 2008, 708 melanoma patients underwent a sentinel node biopsy. The procedure was considered false-negative if a recurrence developed in the basin from which a tumor-free sentinel node had been removed. Of all false-negative cases, the pre-operative images, operative report and pathology slides were reviewed.
RESULTS: Sentinel node biopsy was positive in 164 (23%) of the patients and false-negative in 10 (1.4%), which results in a false-negative rate of 5.7%. Five of the 10 failures occurred in the first year after the sentinel node biopsy was introduced. Causes for these false-negative procedures could be attributed once to the nuclear medicine physician, once to the surgeon and twice to the pathologist.
CONCLUSION: The sentinel node procedure failed to identify involvement in 5.7% of the patients with lymph node metastases. Half of the false-negative biopsies took place in the first year after the procedure was introduced, illustrating the existence of a learning period.