Prediction of nonsentinel lymph node metastasis in malignant melanoma.

BACKGROUND

Sentinel lymph node biopsy (SLNB) is the standard at many institutions caring for melanoma patients. Patients with positive SLNB results are currently offered completion lymph node dissection (CLND) of the affected lymph node basin. This procedure entails considerable morbidity and is often applied to patients with shortened life expectancies. Because 80% of CLNDs yield no additional positive nodes and there is no proof that CLND leads to survival improvement, criteria are needed to limit this procedure to those most likely to harbor nonsentinel lymph node (SLN) metastases.

METHODS

A retrospective review of 349 cases of melanoma from January 1999 to April 2007 that underwent sentinel lymph node biopsy at a single institution was done. Statistical analysis was used to compare two subgroups of patients: a positive CLND group and a negative CLND group. These two groups were compared with regards to multiple variables related to patient demographics, primary tumor characteristics, and SLN tumor burden.

RESULTS

Age and total size of SLN tumor deposit were the factors with the strongest correlation with CLND positivity. By applying a risk score model that uses the cutoff values of age 55 y and SLN tumor deposit of 5 mm, it is possible to predict CLND positivity in SLN-positive melanoma patients.

CONCLUSION

The likelihood of CLND positivity in SLN-positive melanoma patients can be predicted from two criteria readily available: size of SLN tumor deposit and patient age.