The role of microscopic evaluation in the management of cutaneous melanoma

Vital dye is enough for inguinal sentinel lymph node biopsy in melanoma patients

PURPOSE

The importance of gamma probe detection (GPD) combined with vital dye for sentinel node (SN) biopsy is well accepted. We evaluated the efficacy of patent blue dye (PBD) in identifying inguinal SN.

METHODS

Ninety-four cutaneous melanoma patients with inferior extremity lesions were submitted to SNB according to a established protocol. Patients were randomized in two groups: Blue group, where SN was identified by PPD and Probe group, where SN was identified by GPD. The median age was 44.2 years and median Breslow thickness was 2.1 mm. Preoperative lymphoscintigraphy, lymphatic mapping with PBD and intra-operative GPD was performed on all patients. Histological examination of SN consisted of hematoxylin-eosin and immunohistochemical staining. If micrometastases were present complete lymphadenectomy was performed. The SN was considered as identified by PBD if it was blue and identified by GPD if it demonstrated at least ten times greater radioactivity than background.

RESULTS

It was explored 94 inguinal lymphatic basins, 145 SN were excised (70 guided primarily by blue dye and 75 guided primarily by probe). All SN identified by preoperative lymphoscintigraphy were excised. In the Blue group PPD identified all SN and all of them were hot. In the Probe group all SN were identified by probe and were blue. The coincidence of PPD and GPD was 100%.

CONCLUSION

Patent blue dye is enough to identify superficial inguinal SN in cutaneous melanoma.

Prediction of metastatic melanoma in nonsentinel nodes and clinical outcome based on the primary melanoma and the sentinel node

Lymphatic mapping and sentinel node biopsy are well-established techniques for staging and managing patients with melanoma, breast cancer and other malignancies that spread initially to the regional lymph nodes. Identification of tumor in the sentinel node is the most precise staging technique currently available. The sentinel node is the site of metastatic melanoma in approximately 20% of melanoma patients and if tumor is present in the sentinel node it is customary to perform a complete dissection of the lymph nodes of the affected nodal basin. This may be overtreatment for some patients as tumor is identified in the nonsentinel nodes of only one-third of sentinel node-positive melanoma patients treated by completion lymphadenectomy. If it were possible accurately to identify the minority of patients with tumor in the nonsentinel nodes, the patients most likely to benefit from lymphadenectomy, the remaining patients could be spared a potentially morbid operation that is unlikely to confer clinical advantage. In 90 patients with a melanoma-positive sentinel node, who subsequently had a completion lymphadenectomy, we evaluated and compared the capacity of characteristics of the primary melanoma and of the sentinel node to predict individuals likely to have tumor in nonsentinel nodes. We assessed the Breslow thickness of the primary, the amount of tumor in the sentinel node (relative tumor area) and, as an index of immune modulation of the sentinel node, the density of dendritic leukocytes in the nodal paracortex. The relative area of tumor in the sentinel node and Breslow thickness of the primary melanoma most accurately predicted the presence of tumor in the nonsentinel nodes (P=0.0001 in both cases-Wilcoxon rank sums). The presence of melanoma in the nonsentinel nodes was also predicted by the density of dendritic leukocytes in the paracortex (P=0.008-Wilcoxon rank sums). These three observations assessed alone and in combination predict the presence of tumor in the nonsentinel nodes with high accuracy. The same characteristics also significantly correlated with tumor recurrence (tumor burden, P=0.0001, Breslow, P=0.0001 and dendritic cell density, P=0.0007) and death from melanoma (tumor burden, P=0.0001, Breslow, P=0.0001 and dendritic cell density, P=0.0026).

Optimized assessment of sentinel lymph nodes for metastatic melanoma: implications for regional surgery and overall treatment planning

Correct identification of the sentinel node (SN) and accurate evaluation of this node's tumor status constitute the most precise technique for staging clinically localized cutaneous melanoma. However, even if tumor is present in the SN (as in approximately 20% of patients), the remaining nodes in the basin are often tumor-free. We have found that the Breslow thickness of the primary, the relative area of tumor in the SN (with respect to the area of the SN), and the density of dendritic leukocytes in the SN paracortex not only can predict the likelihood of nonsentinel node metastases but also are correlated with likelihood of tumor recurrence and melanoma-specific survival. The most robust of these predictors is relative tumor area, and this may be used as the basis of practical predictive algorithms.

The amount of metastatic melanoma in a sentinel lymph node: does it have prognostic significance?

BACKGROUND

The amount of metastatic disease in the sentinel lymph node (SLN) is examined as a prognostic factor in malignant melanoma.

METHODS

SLN mapping was performed on 592 patients with stage I and II malignant melanoma from March 1, 1994, through December 31, 1999. One hundred four patients were found to have 134 sentinel SLNs containing metastatic melanoma. The slides were reviewed, and the size of the metastatic melanoma in each SLN was measured. The size of the metastatic deposit was defined as macrometastasis (>2 mm), micrometastasis (< or =2 mm), a cluster of cells (10-30 grouped cells) in the subcapsular space or interfollicular zone, or isolated melanoma cells (1 to > or =20 individual cells) in subcapsular sinuses.

RESULTS

The number of metastases in each SLN was isolated melanoma cells, n = 5 (3.7%); cluster of cells, n = 35 (26.1%); < or =2 mm, n = 45 (33.6%); and >2 mm, n = 49 (36.7%). Seventy-nine patients (76%) had a single positive SLN. The size of the largest nodal metastasis was used to stratify patients with multiple positive SLNs. The overall 3-year survival for patients with SLN micrometastases was 90%, versus 58% for patients with SLN macrometastases (P =.004).

CONCLUSIONS

The amount of metastatic melanoma in an SLN is an independent predictor of survival. Patients with SLN metastatic deposits >2 mm in diameter have significantly decreased survival.