Sentinel lymph node biopsy in thin melanoma patients

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.

Use and Costs of Sentinel Lymph Node Biopsy in Non-Ulcerated T1b Melanoma: Analysis of a Population-Based Registry

BACKGROUND

The utility of sentinel lymph node biopsy (SLNB) for non-ulcerated T1b melanoma is debated and associated costs are poorly characterized. Prior work using institutional registries may overestimate the incidence of nodal positivity in this population.

OBJECTIVE

The aim of this study was to estimate the use of SLNB, positivity prevalence, and procedural costs in patients with non-ulcerated T1b melanoma using a population-based registry.

METHODS

We identified patients with clinically node-negative, non-ulcerated melanoma 0.8-1.0 mm thick (T1b according to the 8th edition standard of the American Joint Committee on Cancer) in the Surveillance, Epidemiology, and End Results database from 2010 to 2016. The prevalence of SLNB procedures and positive sentinel nodes were calculated. Factors associated with SLNB and sentinel node positivity were assessed using logistic regression. Medicare reimbursement costs and patient out-of-pocket expenses for SLNB and wide local excision (WLE) versus WLE alone were estimated.

RESULTS

Among 7245 included patients, 3835(53%) underwent SLNB, 156 (4.1%, 95% confidence interval 3.5-4.7) of whom had a positive SLNB. Younger age, >1 mitosis per mm², female sex, and truncal tumor location were associated with higher odds of positivity. The estimated SLNB cost to identify one patient with stage III disease was $71,700 (range $54,648-$83,172). Out-of-pocket expenses for a Medicare patient were estimated to be $652 for a WLE and SLNB and $79 for a WLE alone.

CONCLUSIONS

In this population-based study, only 4% of selected non-ulcerated T1b patients had a positive SLNB, which is lower than prior reports. At the population level, SLNB is associated with high costs per prognostic information gained.

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.

Sentinel node biopsy in patients with primary cutaneous melanoma of any thickness: A cost-effectiveness analysis

OBJECTIVE

To assess the cost-effectiveness of the sentinel node biopsy with lymphadenectomy for nodal metastases (SNB) in patients with primary cutaneous melanoma (CM) of different Breslow thickness (intermediate, thick, thin).

METHODS

Decision tree models were constructed to compare two different strategies of management of patients with CM, wide excision of the primary lesion and SNB and wide excision only (WE). Tree models were created for every Breslow thickness over 1-, 5- and 10-year time horizons. Mean and total direct healthcare costs, life years saved (LYSs), quality-adjusted life years (QALYs), cost effectiveness ratio (CER), and incremental cost effectiveness ratio (ICER) were estimated. Every model was considered as a base case, and its results tested with sensitivity analyses.

RESULTS

Base case analyses showed that the best results were obtained for intermediate CM over 10-year time horizon. In this case, ICER for SNB was 130,508€/QALY, well over the threshold of acceptance (30,000€/QALY). In patients with intermediate CM over 1 and 5 years, and for those with thick and thin CM at any time horizon, negative ICER values were estimated since SNB was proved to be more expensive and less effective than WE. Sensitivity analyses confirmed the robustness of our results.

CONCLUSIONS

SNB caused no improvement in health outcomes in terms of LYSs and QALYs in patients with thick and thin CM, and only a slight benefit in those with intermediate CM. WE was more cost-effective compared with SNB for any CM thickness over any time horizon up to 10 years.

A retrospective, multicenter analysis of the predictive value of mitotic rate for sentinel lymph node (SLN) positivity in thin melanomas

BACKGROUND

There is a paucity of studies to substantiate whether the presence of a single mitosis justifies sentinel lymph node (SLN) biopsy (SLNB) in thin melanomas.

OBJECTIVE

We sought to determine if mitotic rate is associated with SLNB outcome when taking into account other prognostic factors.

METHODS

All cases of melanoma that underwent SLNB in the province of Alberta, Canada, between 2007 and 2013 were reviewed through a provincial tumor database.

RESULTS

A total of 1072 patients fulfilled inclusion criteria. When analyzing all melanomas regardless of thickness, mitotic rate was a good predictor of SLN status. When stratified by Breslow thickness, only intermediate melanomas (1.01-2.0 mm) demonstrated a significant relationship between mitotic rate and positive SLN status (P = .010). For melanomas 1 mm or smaller, mitotic rate was not associated with SLN status. A statistically significant interaction was identified between Breslow thickness and mitotic rate such that for decreasing Breslow depth, the effect of mitotic rate on SLNB status diminished (P = .028).

LIMITATIONS

The study was retrospective in nature. There is underlying variability in mitotic rate reporting methods over time, and between different dermatopathologists.

CONCLUSIONS

Mitotic rate does not have unequivocal utility in predicting SLNB status in thin melanomas. There is a significant interaction between mitotic rate and Breslow depth, such that the predictive value of mitotic rate on SLN positivity may be dependent on Breslow thickness.

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.

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.

Cutaneous malignancies: melanoma and nonmelanoma types

This article reviews melanoma and nonmelanoma cutaneous malignancies.

Lymphatic mapping and sentinel lymph node biopsy in patients with melanoma: a meta-analysis

PURPOSE

To perform a meta-analysis of all published studies of sentinel lymph node (SLN) biopsy for staging patients with melanoma.

METHODS

Published literature in all languages between 1990 and 2009 was critically appraised. Primary outcomes evaluated included the proportion successfully mapped (PSM) and test performance including false-negative rate (FNR), post-test probability negative (PTPN), and positive predictive value in the same nodal basin recurrence.

RESULTS

A total of 71 studies including 25,240 patients met full eligibility criteria. The average PSM was 98.1% (95% CI, 97.3% to 98.6%) and increased with the year of publication, female sex, ulceration, age, and the quality score of the studies. The FNR ranged from 0.0% to 34.0%, averaging 12.5% overall (95% CI, 11% to 14.2%). FNR increased with the length of follow-up (P = .002) but decreased with greater PSM (P = .001). PTPN averaged 3.4% (95% CI, 3.0% to 3.8%), which also increased in studies with longer follow-up, younger age, female sex, deeper Breslow thickness, and with tumor ulceration while decreasing with greater PSM (P < .001). Approximately 20% of the patients with a positive SLN had additional lymph nodes in the complete lymph node dissection and 7.5% of the patients with positive SLN developed recurrence in the same nodal basin which was greater in studies that also reported higher FNR (P = .01).

CONCLUSION

The estimated risk of nodal recurrence after a negative SLN biopsy was ≤ 5% supporting the use of this technology for staging patients with melanoma.

Sentinel lymph nodes in cutaneous melanoma: handling, examination, and clinical repercussion

CONTEXT

Within the last 15 years, evaluation of sentinel lymph nodes (SLNs) has become the most popular method of early staging of several malignancies, including melanoma. Sentinel lymph nodes are usually examined on formalin-fixed, paraffin-embedded sections and by routine histology/immunohistochemistry (research protocols have used other techniques such as polymerase chain reaction). Approximately 20% of patients with cutaneous melanoma have metastasis in the SLN. In most studies, detection of positive SLN conveys a poorer prognosis for patients with cutaneous melanoma.

OBJECTIVE

To review the morphologic patterns of melanoma metastasis in the SLN, the differential diagnosis, and the quantification of tumor burden as a prognostic factor.

DATA SOURCES

Personal observations and review of the pertinent literature.

CONCLUSIONS

Evaluation of sentinel lymph nodes is certainly becoming a widespread technique and most authors agree on its prognostic power for staging patients with cutaneous melanoma. Current studies are evaluating the possible therapeutic value of removal of positive SLNs.

Sentinel Lymph Nodes in Cutaneous Melanoma

Examination of sentinel lymph nodes (SLN) has probably become the most popular method of early staging of patients who have cutaneous melanoma because SLN are considered to be the lymph nodes most likely to contain metastatic deposits; they can be examined in a more intense manner than in standard lymphadenectomy. There are several protocols to examine SLN but most of them use formalin-fixed, paraffin-embedded sections stained with hematoxylin and eosin with the addition of immunohistochemistry. By using these protocols, approximately 20% of patients who have cutaneous melanoma have melanoma cells in the SLN. Current studies are evaluating the possible therapeutic value of removal of positive SLN, but it is accepted by most authors that detection of positive SLN conveys an impaired prognosis for patients who have cutaneous melanoma.

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.

The cost-effectiveness of sentinel node biopsy in patients with intermediate thickness primary cutaneous melanoma

BACKGROUND

The aim of this study was to determine the cost-effectiveness of wide excision (WEX) + sentinel node biopsy (SNB) compared with WEX only in patients with primary melanomas >/=1 mm in thickness.

METHODS

A Markov model was populated with probabilities of disease progression and survival from the published literature. Costs were obtained from diagnostic-related group weightings and health outcomes were measured in quality-adjusted life years (QALYs).

RESULTS

Base case analyses suggested that, over a 20-year timeframe, the mean total cost per patient receiving WEX only was AU $23,182 with 10.45 life years (LY) and 9.90 QALYs. The mean cost per patient for WEX + SNB was AU $24,045 with 10.77 LY and 10.34 QALYs. The incremental cost effectiveness ratio for WEX + SNB was AU $2,770 per LY and AU $1,983 per QALY.

CONCLUSION

WEX + SNB appears to offer an improvement in health outcomes (in both LYs and QALYs) with only a slight increase in cost.

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.

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.