Indications for lymphatic mapping and sentinel lymphadenectomy in patients with thin melanoma (Breslow thickness < or =1.0 mm)

Predictive Values of Pathological and Clinical Risk Factors for Positivity of Sentinel Lymph Node Biopsy in Thin Melanoma: A Systematic Review and Meta-Analysis

Background

The indications for sentinel lymph node biopsy (SLNB) for thin melanoma are still unclear. This meta-analysis aims to determine the positive rate of SLNB in thin melanoma and to summarize the predictive value of different high-risk features for positive results of SLNB.

Methods

Four databases were searched for literature on SLNB performed in patients with thin melanoma published between January 2000 and December 2020. The overall positive rate and positive rate of each high-risk feature were calculated and obtained with 95% confidence intervals (CIs). Both unadjusted odds ratios (ORs) and adjusted ORs (AORs) of high-risk features were analyzed. Pooled effects were estimated using random-effects model meta-analyses.

Results

Sixty-six studies reporting 38,844 patients with thin melanoma who underwent SLNB met the inclusion criteria. The pooled positive rate of SLNB was 5.1% [95% confidence interval (CI) 4.9%-5.3%]. Features significantly predicted a positive result of SLNB were thickness≥0.8 mm [AOR 1.94 (95%CI 1.28-2.95); positive rate 7.0% (95%CI 6.0-8.0%)]; ulceration [AOR 3.09 (95%CI 1.75-5.44); positive rate 4.2% (95%CI 1.8-7.2%)]; mitosis rate >0/mm2 [AOR 1.63 (95%CI 1.13-2.36); positive rate 7.7% (95%CI 6.3-9.1%)]; microsatellites [OR 3.8 (95%CI 1.38-10.47); positive rate 16.6% (95%CI 2.4-36.6%)]; and vertical growth phase [OR 2.76 (95%CI 1.72-4.43); positive rate 8.1% (95%CI 6.3-10.1%)].

Conclusions

The overall positive rate of SLNB in thin melanoma was 5.1%. The strongest predictor for SLN positivity identified was microsatellites on unadjusted analysis and ulceration on adjusted analysis. Breslow thickness ≥0.8 mm and mitosis rate >0/mm² both predict SLN positivity in adjusted analysis and increase the positive rate to 7.0% and 7.7%. We suggest patients with thin melanoma with the above high-risk features should be considered for giving an SLNB.

A Population-Based Comparison of the AJCC 7th and AJCC 8th Editions for Patients Diagnosed with Stage III Cutaneous Malignant Melanoma in Sweden

BACKGROUND

Cutaneous melanoma is steadily increasing worldwide. The new AJCC 8th edition was recently launched and introduced several changes in melanoma staging, particularly for stage III. We conducted a population-based registry study with the purpose to evaluate the impact and prognostic accuracy of the new classification in Sweden.

METHODS

Consecutive patients diagnosed with stage III melanoma between January 2005 and September 2017 were identified by the Swedish Melanoma Registry (SMR) and included for analyses. Patients with multiple primary melanomas were excluded. Patients were classified according to the AJCC 7th as well as the 8th edition. Melanoma-specific survival (MSS) was retrieved from the Swedish Cause of Death Registry.

RESULTS

A total of 2067 eligible patients were identified from the SMR; 1150 patients (57%) changed stage III subgroup when reclassified according to the AJCC 8th edition. The median 5- and 10-year MSS for the whole cohort of stage III melanoma patients was 59% and 51% respectively. The MSS for substage IIIA, B, and C were all improved when patients were reclassified by using to the AJCC 8th edition. The newly defined substage IIID had the worst prognosis with a 10-year MSS of 16%.

CONCLUSIONS

A high proportion of patients diagnosed with stage III melanoma in Sweden between 2005 and 2017 was restaged to another subgroup, when they were reclassified according to the AJCC 8th of staging manual. We established an improved MSS for all substages compared with the former AJCC 7th edition. This may have implications on decisions about adjuvant treatment.

Vertical Growth Phase as a Prognostic Factor for Sentinel Lymph Node Positivity in Thin Melanomas: A Systematic Review and Meta-Analysis

BACKGROUND

The 2010 American Joint Committee on Cancer guidelines recommended consideration of sentinel lymph node biopsy for thin melanoma (Breslow thickness <1.0 mm) with aggressive pathologic features such as ulceration and/or high mitotic rate. The therapeutic benefit of biopsy-based treatment remains controversial. The authors conducted a meta-analysis to estimate the risk and outcomes of sentinel lymph node positivity in thin melanoma, and examined established and potential novel predictors of positivity.

METHODS

Three databases were searched by two independent reviewers for sentinel lymph node positivity in patients with thin melanoma. Study heterogeneity, publication bias, and quality were assessed. Data collected included age, sex, Breslow thickness, mitotic rate, ulceration, regression, Clark level, tumor-infiltrating lymphocytes, and vertical growth phase. Positivity was estimated using a random effects model. Association of positivity and clinicopathologic features was investigated using meta-regression.

RESULTS

Ninety-three studies were identified representing 35,276 patients with thin melanoma who underwent sentinel lymph node biopsy. Of these patients, 952 had a positive sentinel lymph node biopsy, for an event rate of 5.1 percent (95 percent CI, 4.1 to 6.3 percent). Significant associations were identified between positivity and Breslow thickness greater than 0.75 mm but less than 1.0 mm, mitotic rate, ulceration, and Clark level greater than IV. Seven studies reported on vertical growth phase, which was strongly associated with positivity (OR, 4.3; 95 percent CI, 2.5 to 7.7).

CONCLUSIONS

To date, this is the largest meta-analysis to examine predictors of sentinel lymph node biopsy positivity in patients with thin melanoma. Vertical growth phase had a strong association with biopsy positivity, providing support for its inclusion in standardized pathologic reporting.

Association Between Patient Age and Lymph Node Positivity in Thin Melanoma

Importance

More than half of all new melanoma diagnoses present as clinically localized T1 melanoma, yet sentinel lymph node biopsy (SLNB) is controversial in this population given the overall low yield. Guidelines for SLNB have focused on pathologic factors, but patient factors, such as age, are not routinely considered.

Objectives

To identify indicators of lymph node (LN) metastasis in thin melanoma in a large, generalizable data set and to evaluate the association between patient age and LN positivity.

Design, Setting, and Participants

A retrospective cohort study using the National Cancer Database, an oncology database representing patients from more than 1500 hospitals throughout the United States, was performed (2010-2013). Data analysis was conducted from October 1, 2016, to January 15, 2017. A total of 8772 patients with clinical stage I 0.50 to 1.0 mm thin melanoma undergoing wide excision and surgical evaluation of regional LNs were included for study.

Main Outcome and Measures

The primary outcome of interest was presence of melanoma in a biopsied regional LN. Clinicopathologic factors associated with LN positivity were characterized, using logistic regression. Age was categorized as younger than 40 years, 40 to 64 years, and 65 years or older for multivariable analysis. Classification tree analysis was performed to identify high-risk groups for LN positivity.

Results

Among the study cohort (n = 8772), 333 patients had nodal metastases, for an overall positivity rate of 3.8% (95% CI, 3.4%-4.2%). A total of 4087 (54.0%) patients were women. Median age was 56 years (interquartile range [IQR], 46-67) in patients with negative LNs and 52 years (IQR, 41-61) in those with positive LNs (P < .001). In multivariable analysis, younger age, female sex, thickness of 0.76 mm or larger, increasing Clark level, mitoses, ulceration, and lymphovascular invasion were independently associated with LN positivity. In decision tree analysis, patient age was identified as an important risk stratifier for LN metastases, after mitoses and thickness. Patients younger than 40 years with category T1b tumors 0.50 to 0.75 mm, who would generally not be recommended for SLNB, had an LN positivity rate of 5.6% (95% CI, 3.3%-8.6%); conversely, patients 65 years or older with T1b tumors 0.76 mm or larger, who would generally be recommended for SLNB, had an LN positivity rate of only 3.9% (95% CI, 2.7%-5.3%).

Conclusions and Relevance

Patient age is an important factor in estimating lymph node positivity in thin melanoma independent of traditional pathologic factors. Age therefore should be taken into consideration when selecting patients for nodal biopsy.

Sentinel Node Biopsy for Thin Melanomas: Which Patients Should be Considered?

BACKGROUND

As the incidence of melanoma increases, thin melanomas are being diagnosed at an increasingly frequent rate. Currently available prognostic factors are limited in their ability to reliably discriminate which patients will manifest regional nodal metastasis and would be identified early through sentinel node biopsy.

METHODS

We summarized our experience with sentinel node biopsy for patients with cutaneous melanomas less than 1.00 mm in Breslow thickness, with evaluation of Clark level as a predictor of positive sentinel node metastasis.

RESULTS

Among the 409 patients identified, micrometastases were found in the sentinel node in 20 patients, for an overall incidence of nodal progression of 4.9%. A total of 252 (62%) were Clark level II or III (11 of whom had a positive sentinel node) and 157 (38%) were Clark level IV (9 of whom had a positive sentinel node). We reviewed the literature to identify reliable indicators that might be helpful in determining which patients with "thin melanomas" would be likely to manifest regional progression to warrant routinely undergoing a preoperative lymphoscintigraphy followed by a sentinel node biopsy.

CONCLUSIONS

Based on available data, patients with melanomas between 0.75 and 1.00 mm are appropriate candidates to be considered for sentinel node biopsy after discussing the likelihood of finding evidence of nodal progression, the risks of sentinel node biopsy (including the risk of a false-negative result), and the lack of proven survival benefit from any form of surgical nodal staging.

Clinical utilities and biological characteristics of melanoma sentinel lymph nodes

An estimated 73870 people will be diagnosed with melanoma in the United States in 2015, resulting in 9940 deaths. The majority of patients with cutaneous melanomas are cured with wide local excision. However, current evidence supports the use of sentinel lymph node biopsy (SLNB) given the 15%-20% of patients who harbor regional node metastasis. More importantly, the presence or absence of nodal micrometastases has been found to be the most important prognostic factor in early-stage melanoma, particularly in intermediate thickness melanoma. This review examines the development of SLNB for melanoma as a means to determine a patient’s nodal status, the efficacy of SLNB in patients with melanoma, and the biology of melanoma metastatic to sentinel lymph nodes. Prospective randomized trials have guided the development of practice guidelines for use of SLNB for melanoma and have shown the prognostic value of SLNB. Given the rapidly advancing molecular and surgical technologies, the technical aspects of diagnosis, identification, and management of regional lymph nodes in melanoma continues to evolve and to improve. Additionally, there is ongoing research examining both the role of SLNB for specific clinical scenarios and the ways to identify patients who may benefit from completion lymphadenectomy for a positive SLN. Until further data provides sufficient evidence to alter national consensus-based guidelines, SLNB with completion lymphadenectomy remains the standard of care for clinically node-negative patients found to have a positive SLN.

Sentinel Lymph Node Biopsy in Thin Cutaneous Melanoma: A Systematic Review and Meta-Analysis

BACKGROUND

Most patients with melanoma have a thin (≤1.00 mm) lesion. There is uncertainty as to which patients with thin melanoma should undergo sentinel lymph node (SN) biopsy. We sought to quantify the proportion of SN metastases in patients with thin melanoma and to determine the pooled effect of high-risk features of the primary lesion on SN positivity.

METHODS

Published literature between 1980 and 2015 was searched and critically appraised. Primary outcome was the proportion of SN metastases in patients with thin cutaneous melanoma. Secondary outcomes included the effect of high-risk pathological features of the primary lesion on the proportion of SN metastases. Summary measures were estimated by Mantel-Haenszel method using random effects meta-analyses.

RESULTS

Sixty studies (10,928 patients) met the criteria for inclusion. Pooled SN positivity was 4.5 % [95 % confidence interval (CI) 3.8-5.2 %]. Predictors of a positive SN were: thickness ≥0.75 mm [adjusted odds ratio (AOR) 1.90 (95 % CI 1.08-3.34); with a likelihood of SN metastases of 8.8 % (95 % CI 6.4-11.2 %)]; Clark level IV/V [AOR 2.24 (95 % CI 1.23-4.08); with a likelihood of 7.3 % (95 % CI 6.2-8.4 %)]; ≥1 mitoses/mm² [AOR 6.64 (95 % CI 2.77-15.88); pooled likelihood 8.8 % (95 % CI 6.2-11.4 %)]; and the presence of microsatellites [unadjusted OR 6.94 (95 % CI 2.13-22.60); likelihood 26.6 % (95 % CI 4.3-48.9 %)].

CONCLUSIONS

The pooled proportion of SN metastases in thin melanoma is 4.5 %. Thickness ≥0.75 mm, Clark level IV/V, mitoses, and microsatellites significantly increased the odds of SN positivity and should prompt strong consideration of SN biopsy.

Clinicopathologic predictors of sentinel lymph node metastasis in thin melanoma

PURPOSE

Indications for sentinel lymph node biopsy (SLNB) for thin melanoma are continually evolving. We present a large multi-institutional study to determine factors predictive of sentinel lymph node (SLN) metastasis in thin melanoma.

PATIENTS AND METHODS

Retrospective review of the Sentinel Lymph Node Working Group database from 1994 to 2012 identified 1,250 patients who had an SLNB and thin melanomas (≤ 1 mm). Clinicopathologic characteristics were correlated with SLN status and outcome.

RESULTS

SLN metastases were detected in 65 (5.2%) of 1,250 patients. On univariable analysis, rates of Breslow thickness ≥ 0.75 mm, Clark level ≥ IV, ulceration, and absence of regression differed significantly between positive and negative SLN groups (all P < .05). These four variables and mitotic rate were used in multivariable analysis, which demonstrated that Breslow thickness ≥ 0.75 mm (P = .03), Clark level ≥ IV (P = .05), and ulceration (P = .01) significantly predicted SLN metastasis with 6.3%, 7.0%, and 11.6% of the patients with these respective characteristics having SLN disease. Melanomas < 0.75 mm had positive SLN rates of < 5% regardless of Clark level and ulceration status. Median follow-up was 2.6 years. Melanoma-specific survival was significantly worse for patients with positive versus negative SLNs (P = .001).

CONCLUSION

Breslow thickness ≥ 0.75 mm, Clark level ≥ IV, and ulceration significantly predict SLN disease in thin melanoma. Most SLN metastases (86.2%) occur in melanomas ≥ 0.75 mm, with 6.3% of these patients having SLN disease, whereas in melanomas < 0.75 mm, SLN metastasis rates are < 5%. By using a 5% metastasis risk threshold, SLNB is indicated for melanomas ≥ 0.75 mm, but further study is needed to define indications for SLNB in melanomas < 0.75 mm.

Clark level risk stratifies patients with mitogenic thin melanomas for sentinel lymph node biopsy

BACKGROUND

The role for sentinel lymph node biopsy (SLNB) in patients with thin melanoma (≤1 mm) remains controversial. We examined a large cohort of patients with thin melanoma to better define predictors of SLN positivity.

METHODS

From 1995 to 2011, 781 patients with thin primary melanoma and evaluable clinicopathologic data underwent SLNB at our institution. Predictors of SLN positivity were determined using univariate and multivariate regression analyses, and patients were risk-stratified using a classification and regression tree (CART) analysis.

RESULTS

In the study cohort (n = 781), 29 patients (3.7%) had nodal metastases. In the univariate analysis, mitotic rate [odds ratio (OR) = 8.11, p = 0.005], Clark level (OR 4.04, p = 0.003), and thickness (OR 3.33, p = 0.011) were significantly associated with SLN positivity. In the multivariate analysis, MR (OR 7.01) and level IV-V (OR 3.45) remained significant predictors of SLN positivity. CART analysis initially stratified lesions by mitotic rate; nonmitogenic lesions (n = 273) had a 0.7% SLN positivity rate versus 5.6% in mitogenic lesions (n = 425). Mitogenic lesions were further stratified by Clark level; patients with level II-III had a 2.9% SLN positivity rate (n = 205) versus 8.2% with level IV-V (n = 220). With median follow-up of 6.3 years, five SLN-negative patients developed nodal recurrence and four SLN-positive patients died of disease.

CONCLUSIONS

SLN positivity is low in patients with thin melanoma (3.7%) and exceedingly so in nonmitogenic lesions (0.7%). Appreciable rates of SLN positivity can be identified in patients with mitogenic lesions, particularly with concurrent level IV-V regardless of thickness. These factors may guide appropriate selection of patients with thin melanoma for SLNB.

Sentinel node biopsy in thin and thick melanoma

BACKGROUND

Although sentinel node biopsy (SNB) has become standard of care in patients with melanoma, its use in patients with thin or thick melanomas remains a matter of debate.

METHODS

This was a retrospective analysis of patients with thin (≤1 mm) or thick (≥4 mm) melanomas who underwent SNB at two Italian centers between 1998 and 2011. The associations of clinicopathologic features with sentinel lymph node positive status and overall survival (OS) were analyzed.

RESULTS

In 492 patients with thin melanoma, sentinel node was positive for metastatic melanoma in 24 (4.9 %) patients. No sentinel node positivity was detected in patients with primary tumor thickness <0.3 mm. Mitotic rate was the only factor significantly associated with sentinel node positivity (p = 0.0001). Five-year OS was 81 % for patients with positive sentinel node and 93 % for negative sentinel node (p = 0.001). In 298 patients with thick melanoma, 39 % of patients had positive sentinel lymph nodes (median Breslow thickness 5 mm). In patients with positive sentinel node, 93 % had mitotic rate >1/mm(2). Five-year OS was 49 % for patients with positive sentinel lymph nodes and 56 % for patients with negative sentinel nodes (p = 0.005).

CONCLUSIONS

The rate of sentinel node positivity in patients with thin melanoma was 4.9 %. The only clinicopathologic factor related to node positivity was mitotic rate. Given its prognostic importance, SNB should be considered in such patients. SNB should also be the standard method for melanoma ≥4 mm, not only for staging, but also for guiding therapeutic decisions.

Outcome of sentinel lymph node biopsy and prognostic implications of regression in thin malignant melanoma

Thin melanomas with partial or complete regression may provide clues about antitumor immunity, but their management remains controversial. We have characterized the management and clinical outcomes of regressed thin (<1 mm) T1a melanomas and hypothesized that regression increases the risk of regional metastases when compared with nonregressed thin melanomas. A prospectively collected clinical database was reviewed, and T1a melanomas with regression were identified. Histology, surgical approach, outcome, and survival were evaluated. The primary outcome measures were sentinel node positivity, subsequent lymph node metastasis, and survival. A total of 75 patients with T1a or in-situ melanomas were grouped into three subsets. Group 1: 35 underwent a sentinel node biopsy (SNBx), none of which were positive. No patients developed nodal recurrence. The 5-year survival of this group was 93%, with a median follow-up of 52 months. Group 2: 31 were followed up without SNBx; two developed regional nodal disease (6.5%), neither of whom died of subsequent distant disease. The 5-year survival was 89%, with a median follow-up of 38 months. There was no significant difference in the survival between groups 1 and 2. Group 3: nine patients presented with metastatic disease concurrent with a regressed thin melanoma. These patients had a median survival of 2.3 years and a 4-year survival estimate of 22%. Regression should not be used as an indication for SNBx in T1a melanomas; we recommend that such patients be managed with wide local excision and a long-term clinical follow-up. The poor prognosis of thin regressed primary melanoma with simultaneous metastatic disease may indicate the existence of immune escape phenotypes supporting melanoma progression.

Sentinel node biopsy is indicated for thin melanomas ≥0.76 mm

BACKGROUND

A consensus for which patients with thin melanomas (≤1 mm) should undergo sentinel lymph node biopsy (SLNB) is not established. We describe a large single institution experience with SLNB for thin melanomas to determine factors predictive of nodal metastases.

METHODS

Retrospective review from 2005 to 2010 identified 271 patients with thin melanomas who underwent SLNB, along with 13 additional patients not treated with SLNB who developed a nodal recurrence as first site of recurrence. Clinicopathologic characteristics were correlated with nodal status and outcome.

RESULTS

Median age was 55 years, and 53% of patients were male. Median Breslow thickness was 0.85 mm. Overall, a positive sentinel lymph node (SLN) was found in 22 (8.1%) of 271 cases; 8.4% of melanomas ≥0.76 mm were SLN positive with 5% of T1a melanomas ≥0.76 mm and 13% of T1b melanomas ≥0.76 mm having SLN metastases. Only two of 33 highly selected patients with melanomas <0.76 mm (both T1b) had a positive SLN. Logistic regression analysis demonstrated that mitotic rate ≥1/mm(2) significantly correlated with nodal disease (p < 0.05) and ulceration correlated with SLN metastases (p < 0.05). Median follow-up was 2.1 years. Overall survival did not differ between positive and negative SLN patients (p = 0.53) but was worse for patients presenting with a nodal recurrence (p < 0.01).

CONCLUSIONS

SLN metastases were seen in 8.4% of thin melanomas ≥0.76 mm, including 5% of T1a melanomas ≥0.76 mm. We believe these rates are sufficient to justify consideration of SLNB in these patients, while the indications for SLNB in melanomas <0.76 mm remain to be defined.

Sentinel lymph node biopsy in patients with thin primary cutaneous melanoma

OBJECTIVES

To determine the rate and clinicopathologic factors predictive of sentinel lymph node (SLN) positivity, regional lymph node recurrence, and survival in a large series of patients with thin primary cutaneous melanoma who underwent SLN biopsy (SLNB).

METHODS

Patients with thin (≤1 mm) melanomas who underwent SLNB between 1992 and 2009 at Melanoma Institute Australia were identified from the Melanoma Institute Australia database. The association of clinicopathologic features with SLN status, lymph node recurrence, and survival was analyzed.

RESULTS

In 432 patients [226 men, 206 women; median age 49.5 years (range: 14.4-85.0 years)], SLNB was positive for metastatic melanoma in 29 (6.7%) patients. No SLN positivity was detected in 37 patients with primary tumor thickness 0.50 mm or less. Breslow thickness (P = 0.012) and presence of lymphovascular invasion (P = 0.018) were the only factors significantly associated with SLN positivity. Regional lymph node recurrence was significantly more common in tumors located in the head/neck region (4/33, 12%) than in extremities (3/245, 1.2%) and trunk (2/154, 1.3%) (P < 0.001). Primary tumor mitotic rate was a significant predictor of melanoma-specific survival (Hazard Ratio [HR] = 1.2, 95% confidence interval: 1.09-1.35, P < 0.001).

CONCLUSIONS

There is a low but significant rate of SLN positivity in patients with primary melanomas 0.51 to 1.0 mm in thickness. Given its prognostic importance, SLNB should be considered in such patients, particularly if there is lymphatic permeation by melanoma at the primary tumor site. More frequent regional node field recurrences in patients with head/neck primary tumors may be a consequence of complex lymphatic drainage patterns in this region.

Indications of Sentinel Node Biopsy in Thin Melanoma

OBJECTIVE

To assess data on survival, recurrence and histological factors in positive and negative sentinel lymph nodes in thin melanoma cases.

METHODS

A systematic review was conducted on observational studies in four databases (Cochrane Library, Medline, Embase and Lilacs). Positive and negative micrometastases in sentinel lymph node biopsy were compared regarding the clinical outcomes - death and recurrence - and six histological factors - vertical growth phase, Breslow thickness, Clark level, ulceration, regression and mitosis rate.

RESULTS

Positive sentinel lymph node is statistically associated with greater risk of death in six studies (OR: 7.2; 95%CI [2.37-21.83]; I2 0%) and also to recurrence in three studies (OR: 30.7; 95%CI [12.58-74.92]; I2 36%). Comparing positive and negative groups, the histological factors predicting positive sentinel nodes and poor prognosis were: mitosis rate ≥ 5/mm2 (OR: 16.29; 95%CI [3.64-72.84]; I2 40%); VGP (OR: 2.93; 95%CI [1.08-7.93]; I2 59%); Breslow thickness ≥ 0.75mm (OR: 2.23; 95%CI [1.29-3.86]; I2 0%); and Clark level IV-V (OR: 1.61; 95%CI [1.06-2.44]; I234%).

CONCLUSIONS

The statistically significant results associated with the presence of micrometastases in thin melanomas were Breslow thickness ≥ 0.75 mm, Clark level IV-V and mitoses ≥ 5/mm2, absence of regression. This histological factor of ulceration was associated, but not statistically significant.

Predictors of occult nodal metastasis in patients with thin melanoma

HYPOTHESIS

Thin primary lesions are largely responsible for the rapid increase in melanoma incidence, making identification of appropriate candidates for nodal staging in this group critically important. We hypothesized that common clinical variables may accurately estimate the risk of nodal metastasis after wide excision and determine the need for sentinel node biopsy.

DESIGN

Review of prospectively acquired data in a large melanoma database.

SETTING

A tertiary referral center.

PATIENTS

A total of 2211 patients with thin melanoma treated by wide local excision alone were identified in the database between January 1, 1971, and December 31, 2005. Of those, 1732 met entry criteria.

MAIN OUTCOME MEASURES

We examined the rate of regional nodal recurrence and the impact of clinical and demographic variables by univariate and multivariate analyses.

RESULTS

The overall nodal recurrence rate was 2.9%; median time to recurrence was 38.3 months. Univariate analysis of 1732 patients identified male sex (P < .001), increased Breslow thickness (P < .001), and increased Clark level (P < .001) as significant for nodal recurrence. Multivariate analysis identified male sex (hazard ratio, 3.5; 95% confidence interval, 1.8-7.0; P < .001), younger age (0.45; 0.24-0.86; P = .001), and increased Breslow thickness (2.5; 1.6-3.7; categorical P < .001) as significant for nodal recurrence. The Clark level was no longer significant (P = .63). Breslow thickness, age, and sex were used to develop a scoring system and nomogram for the risk of nodal involvement. Predictions ranged from 0.1% in the lowest-risk group to 17.4% in the highest-risk group.

CONCLUSIONS

Many patients with thin melanoma will have nodal recurrence after wide excision alone. Three simple clinical variables may be used to estimate recurrence risk and select patients for sentinel node biopsy.

Multidisciplinary treatment of primary melanoma

This article covers the multidisciplinary treatment of primary melanoma. Excision margins and the need for sentinel lymphadenectomy are mainly dictated by the Breslow thickness although exceptions to this dictum do exist. Interferon is the only FDA approved adjuvant therapy for high risk melanoma although its overall survival benefit is minimal. Trials examining different doses or duration of interferon therapy have not demonstrated any promising survival data so far. There have been several randomized vaccine trials for melanoma but none have shown an overall survival benefit. Research into T-cell regulation continues and will hopefully bring promise for the future of melanoma treatment.

Meta-analysis of sentinel lymph node positivity in thin melanoma (<or=1 mm)

BACKGROUND

Despite the lack of an established survival benefit of sentinel lymph node (SLN) biopsy, this technique has been increasingly applied in the staging of thin (

METHODS

MEDLINE, EMBASE, and Cochrane databases were searched for rates of SLN positivity in patients with thin melanoma. The methodologic quality of included studies was assessed using the Methodological Index for Non-Randomized Studies criteria. Heterogeneity was assessed using the Cochran Q statistic, and publication bias was examined through funnel plot and the Begg and Mazumdar method. Overall SLN positivity in thin melanoma patients was estimated using the DerSimonial-Laird random effect method.

RESULTS

Thirty-four studies comprising 3651 patients met inclusion criteria. The pooled SLN positivity rate was 5.6%. Significant heterogeneity among studies was detected (P = .005). There was no statistical evidence of publication bias (P = .21). Eighteen studies reported select clinical and histopathologic data limited to SLN-positive patients (n = 113). Among the tumors from these patients, 6.1% were ulcerated, 31.5% demonstrated regression, and 47.5% were Clark level IV/V. Only 4 melanoma-related deaths were reported.

CONCLUSIONS

Relatively few patients with thin melanoma have a positive SLN. To the authors' knowledge, there are no clinical or histopathologic criteria that can reliably identify thin melanoma patients who might benefit from this intervention. Given the increasing diagnosis of thin melanoma, in addition to the cost and potential morbidity of this procedure, alternative strategies to identify patients at risk for lymph node disease are needed.

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Key Words Collapse

MESH Headings

• Clinical Trials as Topic
• Female
• Humans
• Lymph Node Excision
• Lymphatic Metastasis
• Male
• Melanoma/secondary
• Middle Aged
• Mitosis
• Periodicals as Topic
• Sentinel Lymph Node Biopsy
• Skin Neoplasms/pathology

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Grants

• P30 CA016087 NCI NIH HHS
• 5 P30 CA 016087-27 NCI NIH HHS

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Affiliation(s)

Melanie A. Warycha Department of Dermatology, New York University School of Medicine, New York, NY
Jan Zakrzewski Department of Dermatology, New York University School of Medicine, New York, NY
Quanhong Ni Division of Biostatistics and Epidemiology, Department of Public Health, Weill Medical College of Cornell University, New York, NY
Richard L. Shapiro Department of Surgery, New York University School of Medicine, New York, NY
Russell S. Berman Department of Surgery, New York University School of Medicine, New York, NY
Anna C. Pavlick Department of Dermatology, New York University School of Medicine, New York, NY Department of Medicine, New York University School of Medicine, New York, NY
David Polsky Department of Dermatology, New York University School of Medicine, New York, NY Department of Pathology, New York University School of Medicine, New York, NY
Madhu Mazumdar Division of Biostatistics and Epidemiology, Department of Public Health, Weill Medical College of Cornell University, New York, NY
Iman Osman Department of Dermatology, New York University School of Medicine, New York, NY Department of Medicine, New York University School of Medicine, New York, NY

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Importance of sentinel lymph node biopsy in patients with thin melanoma

HYPOTHESIS

The status of the sentinel node (SN) confers important prognostic information for patients with thin melanoma.

DESIGN, SETTING, AND PATIENTS

We queried our melanoma database to identify patients undergoing sentinel lymph node biopsy for thin (< or =1.00-mm) cutaneous melanoma at a tertiary care cancer institute. Slides of tumor-positive SNs were reviewed by a melanoma pathologist to confirm nodal status and intranodal tumor burden, defined as isolated tumor cells, micrometastasis, or macrometastasis (< or =0.20, 0.21-2.00, or >2.00 mm, respectively). Nodal status was correlated with patient age and primary tumor depth (< or = 0.25, 0.26-0.50, 0.51-0.75, or 0.76-1.00 mm). Survival was determined by log-rank test.

MAIN OUTCOME MEASURES

Disease-free and melanoma-specific survival.

RESULTS

Of 1592 patients who underwent sentinel lymph node biopsy from 1991 to 2004, 631 (40%) had thin melanomas; 31 of the 631 patients (5%) had a tumor-positive SN. At a median follow-up of 57 months for the 631 patients, the mean (SD) 10-year rate of disease-free survival was 96% (1%) vs 54% (10%) for patients with tumor-negative vs tumor-positive SNs, respectively (P < .001); the mean (SD) 10-year rate of melanoma-specific survival was 98% (1%) vs 83% (8%), respectively (P < .001). Tumor-positive SNs were more common in patients aged 50 years and younger (P = .04). The SN status maintained importance on multivariate analysis for both disease-free survival (P < .001) and melanoma-specific survival (P < .001).

CONCLUSIONS

The status of the SN is significantly linked to survival in patients with thin melanoma. Therefore, sentinel lymph node biopsy should be considered to obtain complete prognostic information.

Surgery and sentinel lymph node biopsy

In patients with melanoma, surgery is pivotal not only for the primary tumor but also for regional and often distant metastases. The minimally invasive technique of sentinel node (SN) biopsy has become standard for detection of occult regional node metastasis in patients with intermediate-thickness primary melanoma; in these patients it has a central role in determining prognosis and a significant impact on survival when biopsy results are positive. Its role in thin melanoma remains under evaluation. The regional tumor-draining SN also is a useful model for studies of melanoma-induced immunosuppression. Although completion lymphadenectomy remains the standard of care for patients with SN metastasis, results of ongoing phase III trials will indicate whether SN biopsy without further lymph node surgery is adequate therapy for certain patients with minimal regional node disease.

The role of sentinel node biopsy in patients with cutaneous melanoma

The role of sentinel lymph node biopsy (SLNB) as a prognostic indicator in melanoma patients has been controversial in the fields of surgical oncology and dermatology for decades. This minimally invasive surgical technique was introduced in 1990 for diagnosing melanoma lymphatic metastases and has been deemed the standard of surgical care of cutaneous malignant melanoma by the World Health Organization and the Sunbelt Melanoma Clinical Trial. Its usefulness as a prognostic indicator of metastases led to expanded applications for breast, colon, gastric, esophageal, head and neck, thyroid, and lung cancers. This article first provides an overview of cutaneous melanoma and staging methods and treatment modalities. A brief study of the lymphatic system and the SLNB procedure are reviewed, followed by a discussion of its usefulness in patients who have melanoma, including risks and benefits. This article also discusses nursing considerations for patients undergoing the procedure, and patient education tips. Lastly, future indications for SLNB and new prognostic indicators for melanoma are discussed.

Sentinel lymph node biopsy in patients with thin melanomas

The aim of the present study is to report our experience with lymphatic mapping (LM) and sentinel lymph node biopsy (SLNB) in a selected group of patients with thin primary cutaneous melanomas. Fifty patients (22 females and 28 males; mean age, 57.8 years; range, 30-77 years) with a mean tumor thickness of 0.63 mm (range, 0.24-1.00 mm) underwent LM/SLNB. Twenty-eight (56%) of them had Clark level II, 20 (40%) had Clark level III, and two (4%) had Clark level IV. Tumor ulceration was present in two patients (4%) and histological regression in 35 patients (70%). Sentinel lymph node (SLN) metastases occurred in two of 50 patients (4%). The first case was a 0.88-mm thick, Clark level III, non-ulcerated superficial spreading melanoma of the trunk, without any regression. The second case was a 0.95-mm thick, Clark level IV, non-ulcerated superficial spreading melanoma of the neck, with regression. Both patients were disease-free 76 and 50 months after the SLNB procedure and followed complete lymph node dissection, respectively. The patients with negative SLN were disease-free after a median follow up of 44 months (mean, 43.2; range, 15-84 months). Published data and our experience suggest that LM/SLNB is not routinely indicated for melanomas less than 0.75 mm. Our results confirmed the accuracy of the new American Joint Committee on Cancer/International Union Against Cancer criteria, in which SLNB is required for thin melanomas less than 1.0 mm when they have ulceration or Clark level IV and V invasion.

Regional Nodal Metastatic Disease Is the Strongest Predictor of Survival in Patients with Thin Vertical Growth Phase Melanomas: A Case for SLN Staging Biopsy in These Patients

BACKGROUND

The benefit of sentinel lymph node (SLN) biopsy for patients with thin (< or =1.0 mm) melanomas, even for prognostic value, is controversial. This may partly result from the relatively small number and short follow-up of SLN-positive patients in this group. Previously, we have shown that clinical regional nodal metastatic disease (RNMD) serves as a good surrogate for SLN positivity. Here, we use RNMD as a validated surrogate for SLN positivity and examine its prognostic value in a large pre-SLN group of patients with thin vertical growth phase (VGP) lesions who would today commonly be offered SLN biopsy in our practice.

METHODS

Between 1972 and 1991, 472 patients with thin VGP melanomas with at least 10 years' follow-up were eligible for the study. Kaplan-Meier survival curves were computed for patients with and without RNMD. A multivariate Cox model and classification tree analysis were used to evaluate clinical and histopathologic predictors of survival.

RESULTS

Sixty-seven patients (14.2%) developed recurrence, 53.7% of whom developed RNMD. Forty-five patients (9.5%) experienced melanoma-related deaths (MRD). The most statistically significant predictor of MRD was RNMD (hazard ratio [HR] 13.5, P < .0001). Thickness (HR 10.5, P = .004), axial location (HR 4.6, P = .001), and age >60 years (HR 2.7, P = .005) additionally were independently associated with an increased risk of MRD. RNMD patients demonstrated a 44.4% 10-year disease-specific mortality.

CONCLUSIONS

RNMD was the most statistically significant factor associated with MRD in patients with thin VGP lesions. This supports the prognostic use of SLN biopsy in this group, recognizing that additional factors, including thickness, axial location, and older age were independently associated with a worse survival outcome.

Current surgical management of melanoma

The surgical management of melanoma has changed dramatically over the last few decades. Through the development and conduction of well-designed, prospective, randomized trials, we have been able to refine the way that we surgically manage patients with melanoma. Indeed, many important issues have been addressed through such trials: the proper surgical margins for the primary melanoma, utility of the elective lymph node dissection and the role for selective lymphadenectomy, to name a few. This review will also discuss what we have learned from past clinical trials and address several issues with regards to where we are going in the future.

Benefit of sentinel lymphadenectomy for patients with nonulcerated cutaneous melanomas in the Breslow range between 0.76 and 1 mm: A follow-up study of 148 patients

Sentinel lymphadenectomy (SLNE) is now internationally accepted for the primary treatment of melanomas thicker than 1 mm. But it is still controversial whether also patients with nonulcerated melanomas in the Breslow range between 0.76 and 1 mm should be included. At the authors' department, 87 of such patients (Group A) underwent SLNE in combination with wide local excision (WLE) of their primary melanomas in the years 1995 to 2001. SLN micrometastases were found in 10 of these patients (11.5%). Radical completion lymph node dissections (CLND) were added in 4 of the 10 patients without revealing any further nodal metastases. All the 87 Group A patients remained free from recurrent disease at a median follow-up time of 74 months. The control Group B from the same department encompassed 61 consecutive stage Ia patients with melanomas in the identical Breslow range, who had undergone only WLE of their primaries without SLNE in the years 1987 to 1993 (median follow-up time 115 months). Five of these 61 patients (8.2%) developed melanoma metastases within 12 to 68 (median 19) months of follow-up, 3 of them initially in regional lymph nodes. Four of the 5 individuals died because of the final distant dissemination of the melanoma. Kaplan-Meier comparisons between Groups A and B with log-rank testing showed a significantly worse outcome of Group B with respect to recurrence-free survival (p = 0.01), regional nodal progression (p = 0.041), distant metastasis (p = 0.023) and melanoma-related mortality (p = 0.03). The overall survival was not significantly different, because expiries not related to melanoma predominated in both groups. Our data suggest that SLNE seems to nearly completely eliminate the risk of melanoma recurrences in patients with melanomas between 0.76 and 1 mm thick.

p16 expression in primary malignant melanoma is associated with prognosis and lymph node status

Lymph node (LN) status is an important prognostic factor in melanoma patients. p16 expression and proliferation rate (MIB-1) of primary melanomas have been suggested as a marker of metastatic potential. In this study, the correlation of p16 expression and the proliferation rate (MIB-1) with LN status and tumor-specific survival was investigated in primary melanomas. MIB-1 and p16 expression were analyzed by immunohistochemistry in 64 patients with primary cutaneous melanoma. Thirty four nevi were used as control. All patients underwent sentinel lymph node staging. Three different p16 staining patterns were observed: a combination of nuclear and cytoplasmic staining, only cytoplasmic staining and absence of p16 expression. All 34 nevi displayed a nuclear and cytoplasmic p16 staining, whereas p16 was negative in 14 of 64 (22%) melanomas. The level of p16 expression gradually decreased from benign nevi to melanoma without metastasis to melanoma with metastasis. There was a significant correlation between cytoplasmic p16 expression and absence of metastasis (p < 0.05). Death of disease correlated with absence of p16 immunostaining (p = 0.01). MIB-1 expression was not associated with survival. These results confirm the relevance of p16 expression as a prognostic marker in melanoma patients. In addition, it was shown that cytoplasmic immunostaining for p16 in primary melanoma might serve as a predictor of the LN status. Therefore, immunohistochemical evaluation for p16 expression is of potential value for treatment planning in melanoma surgery.

Early-Stage Melanoma: Staging Criteria and Prognostic Modeling

Accurate risk assessment is central to the process of making rational surgical and systemic treatment recommendations for melanoma patients and in establishing appropriate clinical trial stratification criteria. The current American Joint Commission on Cancer melanoma staging system incorporated relevant prognostic variables to provide a framework for the estimation of risk for recurrence; however, significant prognostic heterogeneity exists within the stage groupings. In the stage I/II group, survival rates range from 40% to 95% as defined by the combination of tumor thickness and ulceration. The use of novel prognostic factors, such as mitotic rate, sentinel node biopsy, and prognostic modeling using a variety of factors, can minimize this prognostic heterogeneity and provide a more accurate and individualized prognostic profile. Recent modifications in the stage III criteria include the number of positive nodes, whether the nodal disease is microscopic or clinically apparent, and the presence of an ulcerated primary. Through these factors, survival estimates can be provided, but like the stage I/II group, wide ranges in prognosis exist. The complexion of the stage III population is in evolution as a result of increasing numbers of patients being diagnosed as having microscopic sentinel node disease. Contemporary efforts are focused on defining the prognosis and natural history of this group. Through prognostic modeling using the number of nodes involved, ulceration status, and a measure of disease burden--disease in the sentinel node--relatively homogeneous subgroups can be identified. Long-term follow-up of patients staged with PCR molecular techniques on sentinel nodes shows conflicting value in assessing prognosis and therefore cannot be routinely used outside a clinical trial. The combination of genomic profiling using microarray analyses and the development of targeted therapy holds the future promise of individualizing prognosis and therapy.

New American Joint Commission on Cancer Staging System for Melanoma: Prognostic Impact and Future Directions

Accurate melanoma staging is critical in establishing management strategies and estimating disease relapse. Combined with assessment of comorbidities and understanding treatment toxicities, risk assessment is central to offering appropriate surgical or systemic therapies. The American Joint Commission on Cancer (AJCC) melanoma staging system provides survival estimates within anatomically defined disease categories. Newer prognostic factors and methods of prognostic analyses can augment predictions for the presence of micro-metastatic disease and further define the risk for relapse. This article highlights relevant changes, evidence supporting future incorporation of more recently defined prognostic variables, novel approaches used as adjuncts to the current staging system, and future directions of the AJCC staging committee.

Predictors of regional nodal disease in patients with thin melanomas

BACKGROUND

Most melanoma patients present with thin (<or=1.0 mm) lesions. Indications for sentinel lymph node (SLN) biopsy are not well defined for this group. Previously, we reported an association between mitotic rate (MR) and SLN positivity in these patients. The study was limited by a relatively small sample size and low statistical power. In this study, we evaluated a large population of patients with thin melanoma from the pre-SLN era to identify predictors of regional nodal disease (RND) that may serve as a surrogate for SLN positivity.

METHODS

Eight hundred eighty-two patients evaluated between 1972 and 1991 were included in the study. Univariate and multivariate regression analyses were performed by using clinical and histological data to identify factors associated with RND. A multivariate logistic regression model was developed and applied to the previously reported group of patients with thin melanomas who underwent SLN biopsy between 1996 and 2004 for validation.

RESULTS

Thirty-eight patients (4.3%) had evidence of RND. In the multivariate analysis, a MR>0, vertical growth phase (VGP), male sex, and ulceration were statistically significant predictors of RND. Patients at the highest risk according to a classification tree analysis (VGP and MR>0) had an RND rate of 11.9%. The regression model developed predicted well the SLN status in the validation sample.

CONCLUSIONS

Investigation of a large pre-SLN population identified MR>0, ulceration, VGP, and male sex as independently predictive of RND in patients with thin melanomas. These factors may help to identify subgroups of these patients that have clinically significant risks of SLN positivity.

Population-based analysis of lymphatic mapping and sentinel lymphadenectomy utilization for intermediate thickness melanoma

BACKGROUND AND OBJECTIVES

Lymphatic mapping and sentinel lymphadenectomy (LM/SL) is the nodal staging procedure of choice for patients with intermediate thickness melanoma. We hypothesize that a significant portion of these patients are not undergoing LM/SL. We explore factors that influence use of LM/SL.

METHODS

Analysis was performed of all incident cases of invasive cutaneous melanoma in North Carolina between January 1, 1999 and December 31, 2001.

RESULTS

Three thousand four hundred and thirty-six cases of melanoma were reported for 1999-2001. Two hundred and seventy-three cases (8%) were excluded due to metastases. Nine hundred and sixteen cases (29%) were excluded because the T classification was not reported. Of the remaining cases, 1,242 (55%) were intermediate thickness (T2-3); 48% (596/1,242) underwent LM/SL. Subjects >or=60 years old were less likely to receive LM/SL than subjects <60 years (39% vs. 55.4%, P < 0.001). Subjects with head/neck primary tumors were less likely to receive LM/SL than other subjects (33% vs. 51%, P < 0.001). Subjects with T3 tumors were more likely to receive LM/SL than those with T2 tumors (54% vs. 42%, P < 0.001).

CONCLUSIONS

Half of all patients with intermediate thickness melanoma in North Carolina do not receive LM/SL. Use of LM/SL varies by patient age and primary tumor site. Further investigation is warranted to explore these differences.

Results of Sentinel Lymph Node Biopsy in Patients With Thin Melanoma

BACKGROUND

Sentinel lymph node (SLN) biopsy has been shown to be a highly accurate method of staging nodal basins in melanoma patients. Although this technique is widely accepted in patients with intermediate-thickness tumors, it is unclear what the indications are for thin (< or = 1 mm) melanoma.

METHODS

From May 1991 to October 2004, 223 patients with thin melanoma underwent SLN biopsy at Memorial Sloan-Kettering Cancer Center. Most patients with thin melanoma were selected for the procedure because of high-risk clinicopathologic features.

RESULTS

Nodal metastases were found in eight patients (3.6%) who underwent SLN biopsy. All positive SLNs were found in patients with > or = .75 mm-thick and Clark level IV melanoma (8 of 114; 7%). Age, sex, tumor location, thickness, Clark level, ulceration, regression, tumor-infiltrating lymphocytes, mitotic rate, and number of mapped nodal basins were not predictive of positive SLNs (chi(2); P = not significant). With a median follow-up of 25 months, there have been no recurrences or deaths in patients with melanoma < .75 mm. Six patients have had regional and/or systemic recurrences (2.7%), only one of whom had a positive SLN. Three patients have died of melanoma; all had negative SLNs.

CONCLUSIONS

Nodal metastasis in thin melanoma is uncommon, especially in patients with < .75 mm and Clark level II or III melanoma. In our experience, no single clinicopathologic factor was predictive of nodal metastases. The prognostic implications of positive SLNs in thin melanoma remain undefined.

American Joint Committee on Cancer Clinical Stage as a Selection Criterion for Sentinel Lymph Node Biopsy in Thin Melanoma

BACKGROUND

A significant proportion of newly diagnosed melanomas are thin lesions (< or = 1.00 mm). Because tumor thickness correlates with the risk for nodal metastases, sentinel lymph node (SLN) biopsy in this subset is controversial. Incorporating other prognostic factors (Clark level and ulceration), we evaluated the 6th edition American Joint Committee on Cancer (AJCC) clinical stage as a simple and widely applicable guideline for offering SLN biopsy for thin melanoma.

METHODS

This study was a review of a prospective melanoma SLN database from 1993 to 2003 with emphasis on SLN positivity rates based on the 6th edition AJCC primary tumor thickness intervals and clinical stage.

RESULTS

Three hundred five patients underwent SLN biopsy, with an overall positivity rate of 17.7%. By the 6th edition AJCC, lesions < or = 1.00 mm had an SLN positivity rate of 6.6%. By 6th edition clinical stage, SLN positivity rates were 4.9% for stage IA and 10.4% for stage IB. By using stage IA as the criterion for not offering SLN biopsy, this procedure would have been avoided in 46% (39 of 85) of < or = 1.00-mm melanoma patients with a negative SLN.

CONCLUSIONS

Sixth edition AJCC clinical stage IB as a selection criterion for performing SLN biopsy in thin melanoma identifies most patients with a positive SLN while also avoiding a negative SLN biopsy in many patients. Until additional widely accepted and validated selection criteria are available, SLN biopsy for clinical stage IB, but not stage IA, thin melanomas is a reasonable approach.

Sentinel lymph node biopsy in thin melanoma patients

BACKGROUND

We sought to determine the incidence of positive sentinel lymph nodes in thin melanoma (<or=1.0 mm) patients and if subgroups could be identified with a higher risk of occult nodal disease.

METHODS

Patients with <or=1.0 mm lesions treated between 1997 and 2003 were reviewed. Sentinel nodes underwent microscopic analysis including step sectioning and immunohistochemical examination. Some nodes underwent reverse transcriptase-polymerase chain reaction (RT-PCR) evaluation for melanoma markers.

RESULTS

Sixty-four of 107 thin melanoma patients underwent sentinel node biopsy (SNB). Mapped patients were more likely to have Clark >or= III and thicker lesions (mean 0.77 mm vs. 0.47 mm), but were not different in regards to age, sex, or lesion location. Eight percent and 58% of sentinel nodes were positive by routine histology and RT-PCR, respectively. Among mapped patients, younger age was the only significant prognostic factor for node positivity. With a median follow-up of 18 months among all patients, one regional recurrence (at 2 years) has been identified.

CONCLUSIONS

Given the low morbidity of sentinel lymph node biopsy, this procedure should be discussed with selected thin melanoma patients to detect microscopic disease, however PCR positivity by our methods is too commonly seen to be clinically significant in thin melanoma patients and requires additional study.

Should sentinel lymph-node biopsy be used routinely for staging melanoma and breast cancers?

The sentinel lymph node (SLN) is the lymph node that represents the 'gate-keeper' of the lymphatic basin; it is the first node to receive lymphatic drainage from the site of the primary tumor. SLN biopsy is a staging procedure and should be considered as such; it is not meant to be a therapeutic operation. The SLN can be mapped and biopsied using tracer agents (e.g. radiolabelled colloid and/or vital blue dye), which are injected around the primary tumor site. Pathologic analysis of the SLN using a combination of serial sectioning of the node, standard hematoxylin and eosin staining, and immunohistochemistry decreases the false-negative rate compared with traditional nodal processing. SLN biopsy is associated with lower morbidity than full lymphadenectomy. The SLN technique accurately reflects the metastatic status of the regional lymph-node basin; recurrent nodal disease in the mapped basin is rare following a tumor-free SLN biopsy result. The objectives of this review are to provide a current and concise overview of the current literature on SLN biopsy and describe its role in clinical oncology.

Sentinel node metastasectomy in thin ≤1-mm melanoma

BACKGROUND AND AIMS

Sentinel lymph node biopsy (SLNB) has been widely accepted as a precise tool to stage melanoma. In thin T1 melanomas (<or=1 mm), the indication of SLNB is controversial since the risk of nodal metastasis is low. The aim of this study was to assess if SLNB detects occult nodal metastases among patients with thin melanomas.

PATIENTS AND METHODS

SLNB was performed prospectively in 135 patients with invasive melanoma in any depth category, including 56 T1 melanomas.

RESULTS

Nodal metastases were detected in 18% by SLNB, and there were three sentinel-positive thin melanomas, constituting 5% of the T1 cases. Histopathologically, there were no factors of the primary tumors that would have predicted these metastases.

CONCLUSION

SLNB is a precise method to detect clinically silent nodal metastases in thin invasive melanoma. Certain histopathologic features of a thin primary lesion may correlate with the predictive probability of the sentinel node status. We were unable to identify these predictors, but the conclusions from this study are limited by the small sample size. Advanced melanoma is a lethal disease, and accurate staging is essential also in the T1 group. For stage III patients with occult nodal metastases, metastasectomy is a better option for cure than observation.