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

Prognostic factors associated with sentinel lymph node positivity and effect of sentinel status on survival: an analysis of 1049 patients with cutaneous melanoma

Sentinel lymph node biopsy (SLNB) is a widely accepted staging procedure in patients with melanoma. However, it is unclear which factors predict the occurrence of micrometastasis and overall prognosis and whether SLNB should also be performed in patients with thin primary tumors. At our Department of Dermatology, University of Munich (Germany), 1049 consecutive melanoma patients were identified for SLNB between 1996 and 2007, and were followed-up to assess disease-free and overall survival. Of those, a total of 854 patients were analyzed prospectively. Patients with positive SLN were subjected to selective lymphadenectomy. The association of patient characteristics with SLN was assessed by multivariate logistic regression. Survival curves were performed using the Kaplan-Meier method. Cox proportional hazard regression with different adjustments was used to estimate the effect of SLN on survival. The detection rate of SLN was 97.24%, of which 24.9% were metastatic. Significant parameters upon SLN positivity were tumor thickness and nodular type of melanoma. The 5-year overall survival was 90.1 and 58.1% in SLN-negative and SLN-positive patients, respectively. Upon multivariate analysis tumor thickness and SLN status were significant factors influencing both disease-free survival and overall survival. In conclusion, our data confirm that SLNB is relevant as a diagnostic and staging procedure and that tumor thickness is of predictive importance. SLN status should be taken into account when designing clinical trials and informing patients about the probable course of their disease. Our data suggest that in case of a nodular melanoma subtype SLNB should also be considered at a tumor thickness below 1 mm.

Tumor antigen cross-presentation and the dendritic cell: where it all begins?

Dendritic cells (DCs) are professional antigen-presenting cells (APCs) that are critical for the generation of effective cytotoxic T lymphocyte (CTL) responses; however, their function and phenotype are often defective or altered in tumor-bearing hosts, which may limit their capacity to mount an effective tumor-specific CTL response. In particular, the manner in which exogenous tumor antigens are acquired, processed, and cross-presented to CD8 T cells by DCs in tumor-bearing hosts is not well understood, but may have a profound effect on antitumor immunity. In this paper, we have examined the role of DCs in the cross-presentation of tumor antigen in terms of their subset, function, migration, and location with the intention of examining the early processes that contribute to the development of an ineffective anti-tumor immune response.

Sentinel lymph node biopsy in melanoma: Facts and controversies

Three decades after its introduction in the 1990s, the sentinel lymph node biopsy for patients with localized cutaneous melanoma is still the subject of great debate in dermatology. Many questions remain unanswered, and studies currently in progress may or may not bring us any closer to determining the truth about sentinel lymph node biopsy and melanoma. We discuss the effect of sentinel lymph node biopsy on overall survival, the clinical and therapeutic implications of sentinel lymph node biopsy, and the melanoma patients who might be candidates for sentinel lymph node biopsy.

Importance of tumor load in the sentinel node in melanoma: clinical dilemmas

There are two hypotheses to explain melanoma dissemination: first, simultaneous lymphatic and hematogeneous spread, with regional lymph nodes as indicators of metastatic disease; and second, orderly progression, with regional lymph nodes as governors of metastatic disease. The sentinel node (SN) has been defined as the first draining lymph node from a tumor and is harvested with the use of the triple technique and is processed by an extensive pathology protocol. The SN status is a strong prognostic factor for survival (83-94% for SN negative, 56-75% SN-positive patients). False-negative rates are considerable (9-21%). Preliminary results of the MSLT-1 trial did not demonstrate a survival benefit for the SN procedure, although a subgroup analysis indicates a possible benefit. A mathematical model has demonstrated 24% prognostic false positivity. SN tumor burden represents a heterogeneous patient population and is classified most frequently with the Starz, Dewar or Rotterdam Criteria. A completion lymph-node dissection might not be indicated in all SN-positive patients. Patients classified with metastases <0.1 mm by the Rotterdam Criteria have excellent survival rates. Ultrasound-guided fine-needle aspiration cytology is emerging as a staging tool for high-risk patients, but more research is necessary before this can change clinical practice.

Metastatic outgrowth encompasses COL-I, FN1, and POSTN up-regulation and assembly to fibrillar networks regulating cell adhesion, migration, and growth

Although the outgrowth of micrometastases into macrometastases is the rate-limiting step in metastatic progression and the main determinant of cancer fatality, the molecular mechanisms involved have been little studied. Here, we compared the gene expression profiles of melanoma lymph node micro- and macrometastases and unexpectedly found no common up-regulation of any single growth factor/cytokine, except for the cytokine-like SPP1. Importantly, metastatic outgrowth was found to be consistently associated with activation of the transforming growth factor-beta signaling pathway (confirmed by phospho-SMAD2 staining) and concerted up-regulation of POSTN, FN1, COL-I, and VCAN genes-all inducible by transforming growth factor-beta. The encoded extracellular matrix proteins were found to together form intricate fibrillar networks around tumor cell nests in melanoma and breast cancer metastases from various organs. Functional analyses suggested that these newly synthesized protein networks regulate adhesion, migration, and growth of tumor cells, fibroblasts, and endothelial cells. POSTN acted as an anti-adhesive molecule counteracting the adhesive functions of FN1 and COL-I. Further, cellular FN and POSTN were specifically overexpressed in the newly forming/formed tumor blood vessels. Transforming growth factor-beta receptors and the metastasis-related matrix proteins, POSTN and FN1, in particular, may thus provide attractive targets for development of new therapies against disseminated melanoma, breast cancer, and possibly other tumors, by affecting key processes of metastasis: tumor/stromal cell migration, growth, and angiogenesis.

Utility of lymph node assessment for atypical spitzoid melanocytic neoplasms

BACKGROUND

Atypical spitzoid melanocytic neoplasms (ASMN) are cutaneous lesions of uncertain malignant potential, which can be difficult to distinguish from cutaneous melanoma. Sentinel lymph node (SLN) biopsy is a safe and useful prognostic tool for staging melanoma, but its role in staging ASMNs is not established nor is the significance of positive SLNs in these patients known. This study attempts to characterize the significance of nodal disease in ASMN.

METHODS

Patients with ASMNs who presented to the melanoma service from 1992 to 2007 were identified from a prospective database. Histological review was performed by two dermatopathologists. Demographic, treatment, and outcome data were reviewed.

RESULTS

A total of 58 patients with ASMNs were treated during the time analyzed; 31 (53%) underwent wide local excision and observation (WLE); 27 underwent wide excision and SLN biopsy. Median age was 24 (range, 6-60) years. Mean Breslow thickness was 2.9 (range, 0.5-10) mm. Median follow-up was 56 (range, 1-160) months. Ten of 58 (17%) patients had nodal metastasis. Four (13%) of 31 patients who underwent WLE developed nodal recurrences, and 6 of 27 (22%) patients had a positive SLN biopsy. Of patients with positive SLNs, none have recurred after undergoing completion lymphadenectomy. One patient presented with synchronous brain metastasis and inguinal lymphadenopathy and died of disease.

CONCLUSIONS

Nodal status does not seem to convey the same prognosis that it does in standard melanoma. There may be a limited ability for progression within the nodal basin in patients with these lesions. This subset of patients would benefit from genetic data complementing histologic analysis.

Use of fluorescence in situ hybridization (FISH) to distinguish intranodal nevus from metastatic melanoma

With the increase in sentinel lymph node biopsies in melanoma patients, pathologists are frequently confronted with small deposits of morphologically bland melanocytes in the node, which occasionally cannot be readily classified as benign nodal nevi or melanoma. As most melanomas harbor characteristic chromosomal aberrations which can be used to distinguish them from benign nevi, we used fluorescence in-situ hybridization (FISH) with markers for 3 regions on chromosome 6 and 1 on chromosome 11 to determine the presence of chromosomal aberrations in sentinel lymph node specimens with small foci of melanocytes that had been diagnosed as metastatic melanoma or nodal nevi by histopathology. Fifty-nine tissue samples from 41 patients (24 lymph node metastases, 17 with nodal nevi, and 18 of the available corresponding primary melanomas) were analyzed by FISH. Twenty of 24 (83%) cases diagnosed as metastatic melanoma showed aberrations by FISH. Of the 4 negative cases, 3 were unequivocal melanoma metastases, whereas 1 on re-review was histopathologically equivocal. Of the 17 nodal nevi, 1 (6%) also showed aberrations by FISH, whereas the remainder was negative. Multiple aberrations were present in the positive case, some of which were also found in the corresponding primary tumor, suggesting that this case represents a deceptively bland melanoma metastasis that had been misclassified by histomorphology. Our data indicate that FISH is a useful adjunct tool to traditional methods in the diagnostic workup of deposits of melanocytes in lymph nodes that are histopathologically ambiguous.

Influence of sentinel lymph node tumor burden on survival in melanoma

BACKGROUND

Completion lymph node dissection (CLND) is the standard procedure for patients with positive sentinel lymph nodes (SLN). With extensive pathological workup, increased numbers of small metastatic deposits are detected in SLN. This study evaluated the prognostic significance of SLN metastatic deposits < or = 0.2 mm in patients treated in a referral cancer center in Brazil.

METHODS

Patients with stage I/II melanoma, consecutively submitted to a SLN procedure by the same surgeon from 2000 to 2006, were evaluated. All positive SLN and randomly selected negative cases were reviewed by two pathologists. Different prognostic factors and SLN tumor burden were recorded. Additional positive non-SLN after CLND, and disease outcome were evaluated.

RESULTS

Of 381 patients who underwent SLN biopsy, 103 (27%) were positive. The mean/median Breslow tumor thickness in the overall group was 3.4/2.0 mm and in the SLN positive patients was 5.72/4.0 mm. Among these patients, 48 (47%) had metastatic deposits >2 mm (macrometastasis), 49 (47%) had metastatic deposits < or =2 mm but >0.2 mm (micrometastasis), and 6 (6%) had metastatic deposits < or =0.2 mm (submicrometastasis). Additional positive non-SLN were detected in 29% of patients with macrometastasis, in 25% of patients with micrometastasis, and in 0% of patients with submicrometastases. At median follow-up of 35 months, the estimated 3-year overall survival was 92% for negative SLN, 64% for micrometastases, 53% for macrometastases, and 100% for submicrometastases (P < 0.001).

CONCLUSION

In the present study, patients with SLN metastatic deposits < or =0.2 mm had no additional positive non-SLNs, and no recurrences or deaths were recorded, suggesting that their prognosis is equivalent to that of patients with negative SLN.

Significance of sentinel lymph node biopsy in malignant melanoma: overview of international data

The notion of sentinel lymph node (SLN) mapping and its use during surgery for staging cancer was initially reported in 1992, in a study involving patients with malignant melanoma. To date SLN biopsy (SLNB) has emerged as a rational approach for staging regional lymph nodes in patients with clinically node-negative melanoma (stage I and II disease). The significance of SLNB as a staging and prognostic tool in melanoma is widely accepted. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis of the SLN remains very controversial. Whether SLNB improves survival in melanoma patients remains an open question.

Cutting a sentinel lymph node into slices is the optimal first step for examination of sentinel lymph nodes in melanoma patients

The optimal processing for the pathology of sentinel lymph nodes of patients with melanoma is still a matter of debate. We compared two protocols of sentinel lymph node processing, which were consecutively applied. For the first protocol, the sentinel lymph nodes were cut into 1-2 mm thick slices. From each slice, 12 microtome sections were stained (multiple slices protocol). For the second protocol, which is a modification of the recent European Organisation for Research and Treatment of Cancer protocol, the sentinel lymph nodes were bivalved. Five consecutive series of microtome sections, with gaps of 50 microm between them, were prepared from each cut surface (bivalving protocol). H&E and immunohistochemical staining were integral elements of both protocols. A total of 584 sentinel lymph nodes (1.8+/-0.9 per patient) were examined. The percentages of micrometastases (29 versus 27%) and of capsular naevi (13 versus 15%) detected were very similar for both protocols. As shown by multivariate logistic regression, Breslow thickness (P=0.003) and younger age (P=0.01) correlated with nodal metastasis. The type of histological preparation, ulceration and sex were not significant. The multiple slices protocol produced, on average, 4 paraffin blocks and 46 microtome sections per node. The bivalving protocol constantly produced 2 paraffin blocks and 42 microtome sections. For technical processing, the multiple slices protocol required, on average, 38 min per sentinel lymph node, whereas the bivalving protocol required 55 min. Both protocols yielded excellent detection rates with a similar amount of work being required on the part of the pathologist. Compared with the bivalving protocol, the multiple slices protocol was less labor intensive for the technical staff.

Expert opinion in melanoma: the sentinel node; EORTC Melanoma Group recommendations on practical methodology of the measurement of the microanatomic location of metastases and metastatic tumour burden

The sentinel node (SN) status has been recognised to be the most important prognostic factor in melanoma. Many studies have investigated additional factors to further predict survival/lymph node involvement. The EORTC Melanoma Group (MG) has formulated the following question: How should we report the microanatomic location and SN tumour burden? The EORTC MG recommends the following: the EORTC MG SN pathology protocol or a similarly extensive protocol, which has also been proven to be accurate, should be used. Only measure what you can see not what you presume. Cumulative measurements decrease the accuracy and reproducibility of measuring. The most reproducible measure is a single measurement of the maximum diameter of the largest lesion in any direction (1-D). If there is any infiltration into the parenchyma, this lesion can no longer be considered solely subcapsular. Reporting of the microanatomic location of metastases should be an assessment of the entire sentinel node, not only of the largest lesion. Multifocality reflects a scattered metastatic pattern, not to be confused with multiple cohesive foci, which fall under the regular location system. A subcapsular metastasis should have a smooth usually curved outline, not ragged or irregular. We recommend all pathologists to report the following items per positive SN for melanoma patients: the microanatomic location of the metastases according to Dewar et al. for the entire node, the SN Tumour Burden according to the Rotterdam Criteria for the maximum diameter of the largest metastasis expressed as an absolute number, and the SN Tumour Burden stratified per category; <0.1mm or 0.1-1.0mm or >1.0mm.

Prognostic significance of a positive nonsentinel lymph node in cutaneous melanoma

PURPOSE

Sentinel lymph node (SLN) biopsy provides important prognostic information for patients with cutaneous melanoma. There may be additional prognostic significance to melanoma spreading from the SLN to nonsentinel lymph nodes (NSLN). We examined the implications of a positive NSLN for overall and distant disease-free survival.

METHODS

Using a prospectively maintained, Institutional Review Board-approved melanoma database we studied patients who had a cutaneous melanoma, a positive SLN, and a completion lymph node dissection (CLND). Survival was determined using a combination of hospital records and the Social Security Death Index (SSDI). Univariate and multivariate Cox regression analysis was performed to further characterize predictors of overall and distant disease-free survival. Kaplan-Meier analysis was used to generate survival curves.

RESULTS

A total of 429 patients with positive SLN biopsies were identified, with at least one positive NSLN identified in 71 (17%). Median follow-up time was 36.8 months. Presence of a positive NSLN was significantly associated with poor outcome, although long-term survival was possible. Presence of ulceration, high mitotic rate, angiolymphatic invasion, total number of positive nodes, and volume of disease>1% in the SLN were significant predictors of survival on univariate analysis, but lost significance on multivariate. Multivariate Cox analysis revealed several predictors of overall survival: increasing age [hazard ratio (HR) 1.04, P<0.01], Breslow depth (HR 1.76, P<0.01), presence of extracapsular extension in the SLN (HR 2.39, P<0.01), and positive NSLN (HR 1.92, P<0.01).

CONCLUSION

Among node-positive melanoma patients, presence of a positive NSLN is a highly significant poor prognostic sign, even after considering the total number of positive nodes and volume of disease in the SLN. CLND after a positive SLN provides this important prognostic information.

Surgical management of melanoma

Melanoma is an increasing health care problem worldwide. Up to 80,000 cases of melanoma are diagnosed per year and it is the sixth leading cause of cancer death in the United States. The lifetime risk is estimated to be 1 in 75 individuals for the development of melanoma. Surgery remains the mainstay of treatment of melanoma, and in most cases it is curative. Several important surgical issues are discussed in this review, including the extent of surgical margins, Mohs micrographic surgery for melanoma in situ, the use of sentinel lymph node biopsy, the usefulness of lymphadenectomy, isolated limb perfusion, and the role of metastasectomy.

Regional nodal staging for early stage colon cancer in the era of endoscopic resection and N.O.T.E.S

Advanced endoscopic technologies and techniques capable of providing localized resection of colonic primaries are entering clinical practice. As much as Natural Orifice Transluminal Endoscopic Surgery (N.O.T.E.S.) may ultimately provide for transmural resection with narrow margins, intraluminal techniques such as endoscopic submucosal resection can now effect excision of early stage tumors from within the colon. However, the limit on the application of these approaches is oncological providence as current staging requires en bloc mesenteric resection in every case to ensure that adequate nodal assessment is assured. Furthermore, this requirement is also a limiting factor on the advance of innovative procedures such as Single-Incision Laparoscopic Surgery and N.O.T.E.S.-hybrid techniques as these approaches, while likely adept at the definitive management of the primary, have limitations regarding their ability to provide full base mesenteric resection (due mostly to constraints on retraction capacity as well as operating field space and exposure). Therefore a means to accurately and efficiently identify those patients who are truly node negative (and so in whom radical mesenteric lymphadenectomy could be avoided) would allow all of these techniques to advance with a clear focus on address of the primary. This review analyses the current state of the art of regional staging in the colonic mesentery in place of formal lymphadenectomy. It includes deliberation of both preoperative non-invasive testing as well as novel means of employing N.O.T.E.S. approaches to allow direct determination of lymph node status (in particular that of sentinel nodes) by either rapid histopathological examination or by emerging technologies such as Optical Coherence Tomography that may provide optical or 'virtual' biopsy.

Sentinel node tumor burden according to the Rotterdam criteria is the most important prognostic factor for survival in melanoma patients: a multicenter study in 388 patients with positive sentinel nodes

SUMMARY BACKGROUND DATA

The more intensive sentinel node (SN) pathologic workup, the higher the SN-positivity rate. This is characterized by an increased detection of cases with minimal tumor burden (SUB-micrometastasis <0.1 mm), which represents different biology.

METHODS

The slides of positive SN from 3 major centers within the European Organization of Research and Treatment of Cancer (EORTC) Melanoma Group were reviewed and classified according to the Rotterdam Classification of SN Tumor Burden (<0.1 mm; 0.1-1 mm; >1 mm) maximum diameter of the largest metastasis. The predictive value for additional nodal metastases in the completion lymph node dissection (CLND) and disease outcome as disease-free survival (DFS) and overall survival (OS) was calculated.

RESULTS

In 388 SN positive patients, with primary melanoma, median Breslow thickness was 4.00 mm; ulceration was present in 56%. Forty patients (10%) had metastases <0.1 mm. Additional nodal positivity was found in only 1 of 40 patients (3%). At a mean follow-up of 41 months, estimated OS at 5 years was 91% for metastasis <0.1 mm, 61% for 0.1 to 1.0 mm, and 51% for >1.0 mm (P < 0.001). SN tumor burden increased significantly with tumor thickness. When the cut-off value for SUB-micrometastases was taken at <0.2 mm (such as in breast cancer), the survival was 89%, and 10% had additional non-SN nodal positivity.

CONCLUSION

This large multicenter dataset establishes that patients with SUB-micrometastases <0.1 mm have the same prognosis as SN negative patients and can be spared a CLND. A <0.2 mm cut-off for SUB-micrometastases does not seem correct for melanoma, as 10% additional nodal positivity is found.

Positive nonsentinel node status predicts mortality in patients with cutaneous melanoma

While sentinel lymph node biopsy (SLN) is a highly accurate and well-tolerated procedure for patients with cutaneous melanoma, the role of the completion lymph node dissection (CLND) for patients with positive SLN biopsy remains unknown. This study aimed to look at the prognostic value of a positive nonsentinel lymph node (NSLN). A prospectively maintained database identified 222 patients with cutaneous melanoma and a positive SLN biopsy, without evidence of distant disease. All of these patients underwent CLND, and 37 patients (17%) had positive NSLN. With median follow-up of 33 months, patients with negative NSLN had median survival of 104 months, while patients with positive NSLN had median survival of 36 months (p < 0.001). There were no survivors in the patients with positive NSLN beyond 6 years. When patients with an equal number of positive nodes were analyzed, the presence of a positive NSLN was still associated with worse melanoma-specific survival (66 months for NSLN- versus 34 months for NSLN+, p = 0.04). While increasing age, tumor thickness, and male sex were associated with an increased risk of death on multivariate analysis, a positive NSLN was the most important predictor of survival (hazard ratio 2.5). We conclude that positive NSLN is an independent predictor of disease-specific survival in patients with cutaneous melanoma.

False-positive cells in sentinel lymph nodes

Melanoma sentinel lymph nodes (SLN) are carefully evaluated to maximize sensitivity. Examination includes hematoxylin and eosin (H+E) stained sections at multiple levels through the node, with subsequent immunohistochemical (IHC) stains for melanocytic markers if H+E sections are negative for melanoma. However, not all IHC-positive cells in SLN are metastatic melanoma, as evidenced by the presence of MART-1 positive cells in SLN from breast cancer patients with no history of melanoma (so-called 'false-positive' cells). These 'false-positive cells' could be nodal nevus, non-melanocytic cells with cross-reacting antigenic determinants, phagocytic cells containing melanocyte antigens, or possibly melanocytes or melanocyte stem cells liberated at the time of biopsy of the cutaneous melanoma. Examination of SLN requires careful correlation of H+E and IHC findings.

Sentinel lymph node micrometastasis may predict non-sentinel involvement in cutaneous melanoma patients

BACKGROUND AND OBJECTIVES

Cutaneous melanoma patients with positive sentinel lymph node biopsy (SLNB) are being treated with completion lymph node dissection (CLND). The aim of our study was to determine the predictive value of sentinel lymph node (SLN) micrometastases (metastases less than 2 mm in diameter) in assessing further lymph node involvement in CLND.

METHODS

Between 2001 and 2005, we performed 476 SLNB in patients with stages I and II melanoma; 74 had metastases in SLN. We evaluated retrospectively the metastases in SLN according to their size and number. The presence of additional metastases in non-sentinel lymph nodes after CLND was evaluated.

RESULTS

Thirty-nine patients had micrometastases, 22 of them were solitary, 3 were double, and 14 patients had multiple micrometastases in SLN. Out of 22 solitary micrometastases, no patient had additional metastases in non-sentinel lymph nodes. From 3 patients with double micrometastases, 1 patient had further metastases in non-sentinel lymph nodes after CLND. Out of 14 patients with multiple micrometastases, 2 had additional metastases in CLND.

CONCLUSIONS

No patient with a single SLN micrometastasis had further metastases after CLND in our series. CLND may not be beneficial after detecting a single micrometastasis in SLN.

Do micromorphometric features of metastatic deposits within sentinel nodes predict nonsentinel lymph node involvement in melanoma?

INTRODUCTION

Multiple attempts have been made to identify melanoma patients with a positive sentinel lymph node (SLN) who are unlikely to harbor residual disease in the nonsentinel lymph nodes (NSLN). We examined whether the size and location of the metastases within the SLN may help further stratify the risk of additional positive NSLN.

METHODS

A review of our Institutional Review Board (IRB)-approved melanoma database was undertaken to identify all SLN positive patients with SLN micromorphometric features. Univariate logistic regression techniques were used to assess potential significant associations. Decision tree analysis was used to identify which features best predicted patients at low risk for harboring additional disease.

RESULTS

The likelihood of finding additional disease on completion lymph node dissection was significantly associated with primary location on the head and neck or lower extremity (P = 0.01), Breslow thickness >4 mm (P = 0.001), the presence of angiolymphatic invasion (P < 0.0001), satellitosis (P = 0.004), extranodal extension (P = 0.0002), three or more positive SLN (P = 0.02) and tumor burden within the SLN >1% surface area (P = 0.004). Sex, age, mitotic rate, ulceration, Clark level, histologic subtype, regression, and number of SLN removed had no association with finding a positive NSLN. Location of the metastases (capsular, subcapsular or parenchymal) showed no correlation with a positive NSLN. Decision tree analysis incorporating size of the metastatic burden within the SLN along with Breslow thickness can identify melanoma patients with a positive SLN who have a very low risk of harboring additional disease with the NSLN.

CONCLUSION

Size of the metastatic burden within the SLN, measured as a percentage of the surface area, helps stratify the risk of harboring residual disease in the nonsentinel lymph nodes (NSLN), and may allow for selective completion lymphadenectomy.

Microscopic tumor burden in sentinel lymph nodes predicts synchronous nonsentinel lymph node involvement in patients with melanoma

PURPOSE

We and others have demonstrated that additional positive lymph nodes (LNs) are identified in only 8% to 33% of patients with melanoma who have positive sentinel LNs (SLNs) and undergo complete therapeutic LN dissection (cTLND). We sought to determine predictors of additional regional LN involvement in patients with positive SLNs.

PATIENTS AND METHODS

Patients with clinically node-negative melanoma who underwent SLN biopsy (1991 to 2003) and had positive SLNs were identified. Clinicopathologic factors, including extent of microscopic disease within SLNs, were evaluated as potential predictors of positive non-SLNs.

RESULTS

Overall, 359 (16.3%) of the 2,203 patients identified had a positive SLN. Positive non-SLNs were identified in 48 (14.0%) of the 343 patients with positive SLNs who underwent cTLND. On univariate analysis, several measures of SLN microscopic tumor burden, one versus three or more SLNs harvested, tumor thickness more than 2 mm, age older than 50 years, and Clark level higher than III were predictive of positive non-SLNs; primary tumor ulceration and number of positive SLNs had no apparent impact. On multivariable logistic regression analysis, measures of SLN microscopic tumor burden were the most significant independent predictors of positive non-SLNs; tumor thickness more than 2 mm and number of SLNs harvested also predicted additional disease. A model was developed that stratified patients according to their risk for non-SLN involvement.

CONCLUSION

In melanoma patients with positive SLNs, SLN tumor burden, primary tumor thickness, and number of SLNs harvested may be useful in identifying a group at low risk for positive non-SLNs and be spared the potential morbidity of a cTLND.

The survival benefit to patients with positive sentinel node melanoma after completion lymph node dissection may be limited to the subgroup with a primary lesion Breslow thickness greater than 1.0 and less than or equal to 4 mm (pT2-pT3)

BACKGROUND

The survival benefit of sentinel node biopsy is still controversial. The aim of our study was to assess the overall survival (OS; calculated both from the date of primary tumor excision and lymph node dissection) data from two large groups of AJCC 2002 stage-III cutaneous melanoma patients-after completion lymph node dissection (CLND after positive sentinel node biopsy) and after therapeutic LND (TLND for clinically/cytologically detected regional lymph node metastases).

MATERIALS AND METHODS

We analyzed the outcomes for 544 consecutive patients, who underwent CLND (47.4%; 258 patients) or TLND (52.6%; 286 patients) at one institution between December 1994 and January 2005. There were no significant differences between the two groups in terms of age and gender distribution and in the parameters of the primary tumor. Median follow-up time was 36 months (range 6-110 months).

RESULTS

We found no significant differences in OS (from the date of primary tumor excision) between CLND and TLND patients in the groups with primary tumor thicknesses of 1.0 mm or less or greater than 4.0 mm (pT1 and pT4); however, in patients with thicknesses greater than 1.0 mm and 4.0 mm or less (in subgroups pT2 and pT3), we found significantly better OS for CLND than for TLND patients-CLND: median OS not reached, 5-year OS was 57.2% (95%CI: 44.4-70.1%); TLND: median OS 42.1 months, 5-year OS was 37.9% (95%CI: 26.5-49.2%) (P = 0.0006). In the entire CLND and TLND groups, the median OS and 5-year OS rates were 60.5 months and 52.5% (95%CI: 45.6-61.5%) and 38.2 months and 39.5% (95%CI: 32.7-46.5%), respectively. Based on multivariate analysis, we have found that in the CLND group the important factors negatively influencing OS (from the date of lymphadenectomy) are: male gender, features of primary tumor (higher Breslow thickness and presence of ulceration) and features of nodal metastases (extracapsular invasion and number of involved nodes). In the TLND group, however, the negative prognostic factors are: male gender and features of nodal metastases (extracapsular invasion and number of involved nodes) without the impact of primary tumor characteristics.

CONCLUSION

The results of the study demonstrate that the survival benefit after positive sentinel node biopsy with subsequent CLND is probably limited only to the subgroup of patients with primary tumor thicknesses not larger than 4 mm and not less than 1 mm when compared with lymph node dissection of palpable nodes. The primary tumor features have no impact on survival after lymphadenectomy performed for clinically involved nodes.

The influence of sentinel lymph node tumour burden on additional lymph node involvement and disease-free survival in cutaneous melanoma--a retrospective analysis of 392 cases

Twenty per cent of sentinel lymph node (SLN)-positive melanoma patients have positive non-SLN lymph nodes in completion lymph node dissection (CLND). We investigated SLN tumour load, non-sentinel positivity and disease-free survival (DFS) to assess whether certain patients could be spared CLND. Sentinel lymph node biopsy was performed on 392 patients between 1999 and 2005. Median observation period was 38.8 months. Sentinel lymph node tumour load did not predict non-SLN positivity: 30.8% of patients with SLN macrometastases (> or =2 mm) and 16.4% with micrometastases (< or =2 mm) had non-SLN positivity (P=0.09). Tumour recurrences after positive SLNs were more than twice as frequent for SLN macrometastases (51.3%) than for micrometastases (24.6%) (P=0.005). For patients with SLN micrometastases, the DFS analysis was worse (P=0.003) when comparing those with positive non-SLNs (60% recurrences) to those without (17.6% recurrences). This difference did not translate into significant differences in DFS: patients with SLN micrometastasis, either with (P=0.022) or without additional positive non-SLNs (P<0.0001), fared worse than patients with tumour-free SLNs. The 2-mm cutoff for SLN tumour load accurately predicts differences in DFS. Non-SLN positivity in CLND, however, cannot be predicted. Therefore, contrary to other studies, no recommendations concerning discontinuation of CLND based on SLN tumour load can be deduced.

Factors predictive of nonsentinel lymph node involvement and clinical outcome in melanoma patients with metastatic sentinel lymph node

BACKGROUND

Identification of melanoma patients who need completion lymphadenectomy and adjuvant treatment after positive sentinel lymph node (SLN) biopsy would be a fundamental step forward toward personalized medicine. This study tested the hypothesis that the microscopic features of metastatic SLNs might predict not only nonsentinel lymph node (NSLN) status, but also patients' clinical outcomes.

METHODS

A retrospective analysis was performed on 96 consecutive melanoma patients who underwent completion lymphadenectomy after positive SLN biopsy. Patients' age and sex, primary tumor Breslow thickness, number of positive SLNs, the largest diameter and depth of invasion of metastatic deposits in the SLN, S stage, and pattern of nodal involvement were correlated with the presence of metastatic disease in NSLNs as well as with the likelihood of tumor recurrence and patient death.

RESULTS

At pathological examination, 20 patients (20.8%) had metastatic melanoma in the NSLN. Pattern of nodal involvement, depth of invasion of SLN by metastatic disease, and S stage were statistically significantly associated with the presence of metastatic disease in NSLN. Multivariate analysis revealed that only the SLN depth of invasion was an independent predictor of NSLN status (P = .0035). This parameter was also significantly associated with disease-free and overall survival, both by univariate (P < .0001 and P = .0006, respectively) and multivariate (P < .0001 and P = .0013, respectively) survival analysis.

CONCLUSIONS

These findings support further investigation of SLN depth of invasion as a predictive factor of potential clinical use to select patients as candidates for completion lymphadenectomy and adjuvant treatment.

Prognostic false-positivity of the sentinel node in melanoma

It is a basic tenet of the sentinel lymph-node biopsy procedure that all positive sentinel lymph nodes will inevitably progress to palpable nodal recurrence if not removed. Comparison of survival is, therefore, considered permissible among patients with positive sentinel lymph nodes who undergo early lymphadenectomy with that among patients who have delayed lymphadenectomy for palpable regional node metastasis, providing that survival is calculated from the date of wide local excision of the primary tumor. Here, that fundamental assumption is contested and evidence is presented to show that a positive sentinel lymph node might have no adverse prognostic relevance in up to one-third of patients. Furthermore, in the same patients, progression to palpable nodal disease might not have occurred even if the positive sentinel node had not been removed. The term prognostic false-positivity is used to describe this phenomenon. Such patients are incorrectly up-staged, are given inaccurate prognostic information and can undergo unnecessary completion lymphadenectomy and unnecessary adjuvant therapy.

Prognostic significance of isolated HMB45 or Melan A positive cells in Melanoma sentinel lymph nodes

The detection of micrometastases (defined as groups of malignant cells) in the sentinel lymph node (SLN) is an important prognostic tool in melanoma. The use of immunohistochemistry with melanocytic markers such as HMB45 and Melan A increases the detection rate of micrometastases but there are also cases with isolated immunohistochemically positive cells (IPC). To determine the prognostic significance of isolated HMB45 and/or Melan A positive cells in melanoma SLN, we compared the clinical course of 47 patients with IPC to 308 patients with negative SLN and to 122 patients with micrometastases. The mean follow-up was 38.1 months. By Kaplan-Meier analyses, relapse free survival and overall survival of patients with IPC were similar to SLN negative patients, whereas patients with micrometastases had a significantly worse relapse free survival and overall survival. In the 47 patients with IPC, 6 relapses (12.8%) and 3 melanoma-related death (6.4%) occurred, in the SLN negative patients 36 relapses (11.7%) and 17 melanoma-related deaths (5.5%), in the patients with micrometastases 46 relapses (37.7%) and 29 melanoma-related deaths (23.8%). Prognosis of patients with IPC in SLN did not correlate with type of positive staining (HMB45, Melan A, or both), capsular involvement, number of cells, presence of cytologic atypias of IPC, or tumor penetrative depth. In conclusion, with short-term follow-up IPC in melanoma SLN are without prognostic significance.

Sentinel lymph node biopsy in melanoma: a micromorphometric study relating to prognosis and completion lymph node dissection

BACKGROUND

Sentinel lymph node (SLN) positivity has been found to be strongly associated with a poor prognosis in melanoma.

OBJECTIVES

This large referral centre study was conducted: (i) to confirm the powerful prognostic value of SLN biopsy (SLNB); (ii) to correlate patient prognosis to the micromorphometric features of SLN metastasis in SLN-positive patients; and (iii) to correlate these micromorphometric features to the likelihood of positive completion lymph node dissection (CLND).

PATIENTS AND METHODS

SLNB was performed in 455 cases of primary melanoma between January 1999 and December 2004; for patients with positive SLN, the following micromorphometric features were registered: size of the largest metastasis (two diameters), depth of metastasis, number of millimetric slices involved, maximum number of metastases on a single section, presence of intracapsular lymphatic invasion and extracapsular spread. Kaplan-Meier survival curves were compared with the log-rank test; multivariate analysis was performed using a Cox regression model. Dependence of CLND status on micromorphometric features of SLN was assessed by the chi(2) test and predictive values of the different features were evaluated by multivariate analysis using a logistic regression model.

RESULTS

A positive SLN was identified in 98 of our 455 cases. Survival was significantly shorter in SLN-positive patients than in SLN-negative patients. Extracapsular invasion was found to be an independent prognostic factor of disease-free survival; ulceration of the primary and the maximum diameter of the largest metastasis were identified as independent predictive factors of disease-specific survival. Age and the lowest diameter of the largest metastasis were identified as independent predictive criteria of positive CLND, whereas depth of metastasis was not. Positivity of CLND was not significantly associated with a worse prognosis.

CONCLUSIONS

Our study confirms the previously demonstrated strong prognostic value of SLNB. It also confirms the relationship between tumour burden in the SLN (evaluated by the maximum diameter of the largest metastasis) and clinical outcome. We point out a new micromorphometric feature of SLN, which seems to be predictive of CLND status: the lowest diameter of the largest metastasis.

Prediction of Nonsentinel Lymph Node Involvement in Patients with a Positive Sentinel Lymph Node in Malignant Melanoma

Completion lymph node dissection (CLND) is routinely performed after metastatic melanoma is detected at sentinel lymph node (SLN) biopsy. Nonsentinel lymph node (NSLN) involvement is found in less than one-third of the cases. Possible predictors of NSLN involvement are examined. A retrospective review of 70 patients with a positive SLN biopsy for melanoma and drainage to one lymphatic basin was performed. The size of metastatic deposits was defined as macrometastases (>2 mm), micrometastases (≤2 mm), a cluster of cells (10–30 grouped cells) in the subcapsular space or interfollicular zone, or isolated melanoma cells (1–20 or more individual cells) in sub-capsular sinuses. Tumor stage, ulceration, SLN tumor burden, mitoses, number of positive SLNs, and total number of lymph nodes removed were examined as predictors of NSLN involvement after CLND. Two additional models based on SLN tumor burden and the number of nodes biopsied were designed. Nineteen patients (24.3%) were found to have NSLN metastases after CLND. Tumor stage, ulceration, SLN tumor burden, mitoses, number of positive SLN, and number of lymph nodes removed were not statistically significant. Residual disease at CLND stratified by SLN tumor burden was: isolated melanoma cells, 0; cluster of cells, 8 (38.1%); ≤2 mm, 5 (20.8%); and >2 mm, 6 (27.3%). A comparison of the means for the models was not predictive of NSLN involvement. None of the risk factors or models examined could predict nonsentinel lymph node involvement with melanoma. The SLN sample and minimal SLN metastatic disease when defined as isolated clusters of cells warrant further study as a potential indicator against CLND after positive SLN.

Prognostic significance of histopathological parameters in sentinel nodes of melanoma patients

AIMS

The presence of micrometastases in the sentinel lymph node (SLN) is an important prognostic parameter for melanoma patients. The aim was to determine the prognostic relevance of histopathological characteristics of micrometastases in the SLN, which has not been adequately addressed thus far.

METHODS AND RESULTS

In 169 melanoma patients with positive SLN, histopathological features of the SLN were correlated with overall survival (OS) and relapse-free survival (RFS). Tumour burden, expansion of melanoma cells in the periphery (infiltration of capsule) and towards the centre of the SLN [tumour penetrative depth (TPN)] were of prognostic significance for OS and RFS on univariate analysis. Multivariate analysis revealed three independent significant parameters which predict a poor prognosis: presence of infiltration of the SLN capsule, TPN > or = 2 mm and size of the largest tumour deposit > or = 30 cells.

CONCLUSIONS

Histopathological analysis of SLN allows the identification of patients with a poor prognosis depending on the location of melanoma cells and tumour burden.