Evaluation of new putative tumor markers for melanoma

BACKGROUND

The early diagnosis of recurrent melanoma can contribute to better outcome if the disease can be surgically resected or if the metastases are responsive to systemic therapies. Lipid-associated sialic acid (LASA-P) and the S-100 protein (S-100) were evaluated as tumor markers for melanoma with the goal of early detection of recurrence.

METHODS

Sixty-seven patients were identified who had levels of S-100 and LASA-P drawn during their clinical course. A multivariate regression analysis was performed to determine the significance of the serum markers in relation to other prognostic factors for melanoma.

RESULTS

After a median follow-up of 30 months, 58 patients had recurrences, and 49 patients died of disease. LASA-P elevation was not associated with the time to recurrence (p = 0.2176) or survival (p = 0.2507). S-100 positivity was a significant predictor of recurrence (p < 0.0001) and survival (p = 0.0059). The median time to recurrence for S-100-positive and S-100-negative patients was 7.6 and 33.8 months, respectively. The median survival time was 59.2 months for S-100-negative patients and 29.6 months for patients positive for S-100.

CONCLUSIONS

Serum S-100 shows significant correlations to both time to recurrence and survival and could be useful in the clinical detection of malignant melanoma.

The use of intraoperative radiolymphoscintigraphy for sentinel node biopsy in patients with malignant melanoma

BACKGROUND

Selective lymphadenectomy or "sentinel node" biopsy has been introduced recently by Morton and colleagues (Arch Surg 1992;127:392-9) to stage patients with intermediate and thick malignant melanomas. It has proven to be an effective way to identify nodal basins at risk for metastasis without the morbidity of a complete lymph node dissection. The majority of biopsies can be performed under local anesthesia with small incisions, but technical difficulties occasionally result in unsuccessful explorations. Identification of the sentinel node can be enhanced by a intraoperative radiolymphoscintigraphy, a technique introduced Alex and Krag (Surg Oncol 1993;137-43) that uses radiolabeled sulfur colloid and a hand-held gamma probe.

OBJECTIVE

We used intraoperative radiolymphoscintigraphy in conjunction with 1% lymphazurin blue dye to define the sentinel node(s) in 148 patients with greater than 0.76 mm in thickness or Clark level IV melanomas. Sentinel lymph nodes were isolated, harvested, and examined using conventional histopathology, and immunohistochemistry for S-100 and HMB-45 antibodies.

RESULTS

The overall success rate of sentinel lymph node localization was 97% using a combination of the two techniques. Twenty-one (14%) patients had micrometastasis, and 17 of these subsequently underwent complete lymph node dissection. A total of 220 of 275 (80%) sentinel nodes harvested were radioactive or "hot" compared with 165 of 275 (60%) with the blue dye alone. Four of the patients with micrometastasis had sentinel nodes positive by gamma probe, but negative by blue dye mapping techniques.

CONCLUSION

Our results suggest that intraoperative radiolymphoscintigraphy using a hand-held gamma detecting probe improves the identification of sentinel lymph nodes during selective lymphadenectomy. This may reduce the number of "unsuccessful explorations" using the vital blue dye technique for lymphatic mapping, and appeal to a greater variety of surgeons, including dermatologic surgeons.

The tumor biology of melanoma nodal metastases

Approximately 20 per cent of melanomas greater than 0.76 mm in thickness will metastasize to the regional lymph nodes if treated with wide local excision alone (WLE). Elective lymph node dissection (ELND) is associated with significant morbidity, which includes lymphedema, wound complications, and paresthesias of the extremity. An alternative operative approach uses selective lymphadenectomy with the identification of the sentinel node, defined as the first node in the lymphatic basin that drains the primary cutaneous site. This study consisted of 132 patients with melanomas greater than 0.76 mm. One hundred nine patients (83%) had histologic negative sentinel nodes, and 23 patients (17%) had one or more sentinel nodes positive for disease. In patients with metastatic disease, 30/35 (86%) sentinel nodes were positive, and 25/357 (7%) nonsentinel nodes were positive (P < 0.001). In 18 patients (78%) of the 23 patients with metastatic disease, the sentinel node was the only node positive, strongly suggesting that there is an orderly progression of metastases. Two patients developed metastatic nodal disease after removal of a negative sentinel node (false negative rate = 1.5). The mean follow-up was 1 year. Sentinel node histology reflects the histology of the remainder of the nodes in the lymphatic basin and "skip" metastases, defined as a negative sentinel node but positive nodes higher in the regional chain positive for metastases or an axillary recurrence after a negative sentinel node biopsy, are rare for malignant melanoma. Harvesting the sentinel node in patients with intermediate or greater thickness melanoma will, therefore, identify a subset of patients with metastatic disease who have the most to benefit from a complete node dissection. This surgical approach allows for complete pathological staging and therapeutic management of patients while significantly reducing expense and overall morbidity.

The role of selective lymphadenectomy in the management of patients with malignant melanoma

BACKGROUND

A novel surgical technique based on selective lymphadenectomy was used to stage 132 patients with intermediate and thick cutaneous malignant melanoma. Preoperative and intraoperative lymph node mapping techniques were used to ascertain regional lymph node basins at risk for metastasis, and to identify the first node(s) the afferent lymphatics encounter in the basin, defined as the "sentinel" node(s). It has been shown that the histology of the sentinel node reflects the histology of the rest of the nodal bain, and according to preliminary studies using this technique, the likelihood of bypassing the sentinel node(s) to "higher" level nodes is less than 2%. Epidemiologic studies indicate that the long-term survival of patients with melanomas of intermediate thickness or greater is significantly compromised if regional lymph nodes are involved. Yet, the utility of performing lymph node dissections for the purposes of staging only is controversial, not only because of the morbidity and expense of the procedure, but the lack of proven survival benefit.

OBJECTIVE

In the present study, we performed preoperative and intraoperative lymphatic mapping, harvested clinically normal sentinel nodes, and examined them for micrometastasis by light microscopy. Both conventional stains and immunocytochemistry for S-100 protein and HMB-45 antibodies were performed, and only those patients with documented micrometastasis received complete lymph node dissections.

RESULTS

The sentinel node(s) was identified in each of the patients. Micrometastatic disease was detected in 31 (23%) of the patients by selective lymphadenectomy, and the sentinel node(s) was the only node involved in 83% of the cases upon subsequent complete nodal dissection.

CONCLUSION

Our preliminary results suggest that selective lymphadenectomy following lymphatic mapping is an effective procedure for staging melanoma patients with lesions of intermediate thickness or greater. Our results indicate that sentinel lymph nodes may be successfully identified and harvested in the majority of patients, and that they may be examined for the first evidence of micrometastasis without the need of a complete nodal dissection. Information as to whether micrometastases are present in the sentinel node would be valuable in staging patients, and identifying candidates for complete nodal dissections. We are participating in a National Cancer Institute-sponsored multicenter trial to ascertain whether this surgical approach can impact on the recurrence rate and survival of patients with stage 1 and 2 melanoma.