The role of preoperative lymphoscintigraphy in surgery planning for sentinel lymph node biopsy in malignant melanoma.

AIM

To evaluate four years of preoperative lymphoscintigraphy experience and the accuracy of sentinel lymph node biopsy in our institution in melanoma patients with various tumor thicknesses. An additional aim was to evaluate the recurrence rate related to pathohistological findings.

METHODS AND PATIENTS

During the period from February 2002 to November 2005, 201 patients underwent sentinel node biopsy. Lymphoscintigraphy for identification of sentinel nodes was performed four to six hours prior to operation of the patient. Sentinel lymph node biopsy using an intraoperative hand-held gamma probe was performed in all patients, together with wide local excision of biopsy wound or primary lesion (N=56). Immediate complete basin dissection was performed in patients with sentinel node metastases. In four patients delayed complete lymph node dissection was performed after definitive histopathologic examination of sentinel nodes. The accuracy of sentinel node biopsy was determined by comparing the intraoperative rates of sentinel node identification and the subsequent development of nodal metastases in regional nodal basins in patients with tumor-negative sentinel nodes and in those with tumorpositive sentinel nodes.

RESULTS

Using preoperative lymphoscintigraphy, we identified sentinel nodes in all but one of the 201 patients (99.0%), and in 248 nodal basins (1.2/patient) we observed 372 sentinel nodes (1.52 sentinels/basin; 1.8 sentinels/patient). The highest number of sentinel nodes was noticed in the groin of patients with melanoma on the lower extremities (1.5/patient), followed by the axilla (1.3/patient). Anomalous lymphatic drainage patterns were observed in 15.0% of all patients. The identification rate of sentinel nodes was 99.0% overall: 100% for the groin basins, and 98.0% for the axilla and head and neck basin. Forty-two patients (20.8%) had tumor-positive sentinel nodes. Ten patients (5.0%) had local or distant recurrences during a median follow-up of 23.1 months (range 2-46). The rate of false-negative lymphatic mapping and sentinel node biopsy as measured by nodal recurrence in patients with tumor-negative sentinel nodes was 1.3%. During the follow-up period, three of 201 patients died from other diseases and three patients died as the result of melanoma metastases, with a median follow-up of 13.5 months (range 12-22).

CONCLUSION

Preoperative lymphoscintigraphy is a sensitive, inexpensive and essential method for the identification of drainage basins, determination of the number and position of sentinel nodes and their location outside the usual nodal basins. Scintigraphic findings may lead to changes in surgical management due to the unpredictability of lymphatic drainage. The low incidence of regional disease recurrence in patients with tumor-negative sentinel nodes supports the use of preoperative lymphoscintigraphy and sentinel node biopsy as a safe and accurate procedure for staging the regional nodal basin in patients with malignant melanoma.