Sentinel node staging of primary melanoma by the “10% rule”: pathology and clinical outcomes

Hot dots - which nodes should be removed in sentinel lymph node biopsy for melanoma?

BACKGROUND

Sentinel lymph node biopsy (SLNB) is a critical staging tool for melanoma patients. The optimal number of lymph nodes removed in SLNB remains unclear. In this study, we retrospectively analysed and tested different criteria for selecting sentinel lymph nodes (SLNs) by radiotracer uptake and blue dye, and their impact on nodal staging. We also evaluated the association between SLN tumour burden and radiotracer uptake.

METHODS

The study population consisted of melanoma patients undergoing SLNB. During the operation all radioactive and blue nodes were removed and sent for histopathological analysis. The ex vivo radioactive count and presence of blue dye of each node were recorded, and these were correlated with presence and size of metastasis in each SLN.

RESULTS

Altogether 175 patients with clinically occult metastasis presented with one or more positive, i.e. metastatic, SLNs. The mean number of lymph nodes removed was 4.5, and the mean number of positive lymph nodes was 1.5 per patient. The most radioactive or hottest node was negative in 38 patients (22%). By removing the hottest node and all nodes with radioactivity >10% of the hottest node, 97% of patients would have been staged correctly. In five patients, metastasis was found solely in a SLN with radioactivity <10% of the hottest node. Of all 267 positive nodes removed, 125 (47%) contained blue dye. Patients with a negative hottest node were associated with lower SLN tumour burden.

CONCLUSIONS

By removing the hottest node and all nodes with radioactivity >10% of the hottest node, 97% of patients with SLN metastases are correctly staged with or without using blue dye.

Cranial nerve outcomes in regionally recurrent head & neck melanoma after sentinel lymph node biopsy

OBJECTIVE

Characterize long-term cranial nerve (CN) outcomes following sentinel lymph node biopsy (SLNB) based management for head and neck cutaneous melanoma (HNCM).

METHODS

Longitudinal review of HNCM patients undergoing SLNB from 1997-2007.

RESULTS

Three hundred fifty-six patients were identified, with mean age 53.5 ± 19.0 years, mean Breslow depth 2.52 ± 1.87 mm, and 4.9 years median follow-up. One hundred five (29.4%) patients had SLNB mapping to the parotid basin. Eighteen patients had positive parotid SLNs and underwent immediate parotidectomy / immediate completion lymph node dissection (iCLND), with six possessing positive parotid non-sentinel lymph nodes (NSLNs). Fifty-two of 356 (14.6%) patients developed delayed regional recurrences, including 20 total intraparotid recurrences: five following false negative (FN) parotid SLNB, three following prior immediate superficial parotidectomy, two following iCLND without parotidectomy, and the remaining 12 parotid recurrences had negative extraparotid SLNBs. Parotid recurrences were multiple (4.9 mean recurrent nodes) and advanced (n = 4 extracapsular extension), and all required salvage dissection including parotidectomy. Immediate parotidectomy/iCLND led to no permanent CN injuries. Delayed regional HNCM macrometastasis precipitated 16 total permanent CN injuries in 13 patients: 10 CN VII, five CN XI, and one CN XII deficits. Fifty percent (n = 10) of parotid recurrences caused ≥1 permanent CN deficits.

CONCLUSIONS

Regional HNCM macrometastases and salvage dissection confer marked CN injury risk, whereas early surgical intervention via SLNB ± iCLND ± immediate parotidectomy yielded no CN injuries. Further, superficial parotidectomy performed in parotid-mapping HNCM does not obviate delayed intraparotid recurrences, which increase risk of CN VII injury. Despite lack of a published disease-specific survival advantage in melanoma, early disease control in cervical and parotid basins is paramount to minimize CN complications.

LEVEL OF EVIDENCE

4 (retrospective case series) Laryngoscope, 130:1707-1714, 2020.

Sentinel Lymph Node Biopsy for Melanoma: Comparison of Lymphocele Rates by Surgical Technique

Lymphocele is a common wound complication of sentinel lymph node biopsy (SLNB). The surgical technique may play a key role in lymphocele formation. This study compared rates of postoperative lymphocele formation by different surgical techniques (Harmonic Scalpel [HS], LigaSure [LS], and traditional electrocautery with clips) after SLNB in the groin or axilla for the staging of clinically node-negative cutaneous melanoma. Patients were selected by convenience sample from a single-institution, single-surgeon, prospectively collected melanoma database over a 27-month period. One hundred fifty consecutive patients underwent SLNB, 70 with clips, 37 with HS, and 43 with LS. The median number of nodes removed was two and did not vary significantly between groups. Twenty-three lymphoceles occurred for an overall rate of 15 per cent; rates were 9.9 and 26.5 per cent for the axilla and groin, respectively. Sixteen (70%) were aspirated for size or symptoms; lymphoceles after groin SLNB were significantly (P = 0.03) more likely to require aspiration. Lymphocele rates for the clip, HS, and LS groups were 20.0, 18.9, and 4.7 per cent, respectively. The differences between the LS and other groups were statistically significant. Use of the LS may lead to lower lymphocele rates after groin and axillary SLNB compared with electrocautery and clips.

Sentinel Lymph Node Biopsy in Head and Neck Melanoma: Long-term Outcomes, Prognostic Value, Accuracy, and Safety

OBJECTIVE

To evaluate the long-term outcomes of sentinel lymph node biopsy (SLNB) for head and neck cutaneous melanoma (HNCM).

STUDY DESIGN

Retrospective cohort study.

SETTING

Tertiary academic medical center.

SUBJECTS AND METHODS

Longitudinal review of a 356-patient cohort with HNCM undergoing SLNB from 1997 to 2007.

RESULTS

Descriptive characteristics included the following: age, 53.5 ± 19 years (mean ± SD); sex, 26.8% female; median follow-up, 4.9 years; and Breslow depth, 2.52 ± 1.87 mm. Overall, 75 (21.1%) patients had a positive SLNB. Among patients undergoing completion lymph node dissection following positive SLNB, 20 (27.4%) had at least 1 additional positive nonsentinel lymph node. Eighteen patients with local control and negative SLNB developed regional disease, indicating a false omission rate of 6.4%, including 10 recurrences in previously unsampled basins. Ten-year overall survival (OS) and melanoma-specific survival (MSS) were significantly greater in the negative sentinel lymph node (SLN) cohort (OS, 61% [95% CI, 0.549-0.677]; MSS, 81.9% [95% CI, 0.769-0.873]) than the positive SLN cohort (OS, 31% [95% CI, 0.162-0.677]; MSS, 60.3% [95% CI, 0.464-0.785]) and positive SLN/positive nonsentinel lymph node cohort (OS, 8.4% [95% CI, 0.015-0.474]; MSS, 9.6% [95% CI, 0.017-0.536]). OS was significantly associated with SLN positivity (hazard ratio [HR], 2.39; P < .01), immunosuppression (HR, 2.37; P < .01), angiolymphatic invasion (HR, 1.91; P < .01), and ulceration (HR, 1.86; P < .01). SLN positivity (HR, 3.13; P < .01), angiolymphatic invasion (HR, 3.19; P < .01), and number of mitoses (P = .0002) were significantly associated with MSS. Immunosuppression (HR, 3.01; P < .01) and SLN status (HR, 2.84; P < .01) were associated with recurrence-free survival, and immunosuppression was the only factor significantly associated with regional recurrence (HR, 6.59; P < .01).

CONCLUSIONS

Long-term follow up indicates that SLNB showcases durable accuracy, safety, and prognostic importance for cutaneous HNCM.

Sentinel lymph node biopsy in melanoma: Which hot nodes should be harvested and is blue dye really necessary?

OBJECTIVES

The '10% rule' has become widely accepted by surgeons performing sentinel lymph node biopsy (SLNB) for melanoma. The purpose of this study was to compare the '10% rule' with alternative node harvesting criteria. In particular, we were interested to see whether the use of blue dye had any impact on the sensitivity of the test and whether it is necessary to remove all hot nodes.

METHODS

We reviewed 537 SLNBs performed for primary melanoma from 2009-2015. SLNB was offered to all patients with 1-4 mm Breslow thickness melanoma and sentinel nodes were harvested according to the '10% rule'.

RESULTS

One hundred sixteen patients (22%) had at least one positive sentinel node and there were 45 positive nodal basins from which more than one sentinel node had been harvested. Excluding blue dye and sampling only hot nodes would have enabled a 5% reduction in nodes harvested, without any compromise in the sensitivity of the test. However, applying harvesting criteria whereby not all hot nodes are taken was associated with a loss of sensitivity, with positive sentinel nodes being missed and patients understaged.

CONCLUSIONS

Our data do not support the continued use of blue dye in SLNB for melanoma, as it does not improve the sensitivity of the test. This series adds to growing evidence, suggesting that the '10% rule' with the inclusion of blue nodes should be reconsidered and that radiocolloid tracer alone is sufficient for sentinel node localisation.

Accuracy of sentinel lymph node mapping in detecting occult neck metastasis in papillary thyroid carcinoma

OBJECTIVES

The objectives of this study were to evaluate the following: 1) the accuracy of sentinel lymph node mapping (SLNM) in detecting metastasis in papillary thyroid carcinoma (PTC), and 2) if SLNM could modify the American Joint Committee on Cancer (AJCC) staging of previous cN0 PTC patients.

SUBJECTS AND METHODS

Forty SLNM were performed prospectively in 38 consecutive cN0 PTC patients, with total thyroidectomy and elective compartment neck dissection (CND). The results of SLNM were compared with CND pathological findings to verify the accuracy of sentinel SLNM.

RESULTS

The mean patients' follow-up was 36 months. A total of 133 SLN were found at levels VI, II, III and IV. The SLN was identified in 95% of the patients with one false negative, 95% sensitivity, a 94% negative predictive value and 97% accuracy. The SLNM upstaging from cN0 to pN+ was 49%, and to stages III and IVa, it was 21%.

CONCLUSIONS

For this series of cN0 PTC patients: 1) SLNM accuracy was 97%, and 2) SLNM upstaging from cN0 to pN+ was 49%, whereas to stages III and IVa, it was 21%.

Patients with sentinel lymph node positive melanoma: Who needs completion lymph node dissection?

INTRODUCTION

Completion lymph node dissection (CLND) for melanoma after positive sentinel lymph node biopsy (SLNB) was recently shown to improve regional but not overall survival, likely due to the majority of patients harboring no further nodal disease. We sought to determine predictors of non-sentinel node (NSN) positivity.

METHODS

Retrospective review of prospectively collected data on melanoma patients undergoing SLNB.

RESULTS

116 patients underwent 119 CLNDs. The incidence of NSN positivity was 17.6%; the average number of positive NSNs in those cases was 1.5. Cervical and inguinofemoral location were most likely to yield positive NSN(s) (40% each). Conversely, the axilla was least likely at 18% (p < 0.001). The average number of nodes harvested was 13 for NSN negative cases and 20 for NSN positive cases (p = 0.005). Tumor thickness increased the probability of positive NSN(s) (OR 1.2, p = 0.02).

CONCLUSIONS

Tumor thickness and nodal basin were predictors of NSN metastasis, factors that could help determine which patients may benefit from CLND. Further, CLNDs with fewer nodes may inadequately clear residual nodal disease.

Is pelvic sentinel node biopsy necessary for lower extremity and trunk melanomas?

OBJECTIVE

There is currently no consensus regarding how to address pelvic sentinel lymph nodes (PSLNs) in melanoma. Thus, our objectives were to identify the incidence and clinical impact of PSLNs.

METHODS

Retrospective review of a prospectively collected multi-institutional melanoma database.

RESULTS

Of 2476 cases of lower extremity and trunk melanomas, 227 (9%) drained to PSLNs (181 to both PSLNs and superficial (inguinal or femoral) sentinel lymph nodes (SSLN) and 46 to PSLNs alone). Seventeen (7.5%) of 227 PSLN cases were positive for nodal metastasis, 8 of which drained to PSLNs only while 9 drained to both PSLNs and SSLNs. Complication rates between PSLN and SSLN biopsy were similar (15% vs. 14% respectively). In 181 cases with drainage to both SSLNs and PSLNs, PSLN biopsy upstaged one patient (0.6%), and completion dissection based on a positive PSLN did not upstage any.

CONCLUSIONS

PSLN biopsy is safe, however in the setting of negative SSLNs there is minimal clinical impact. We therefore recommend PSLN biopsy when the SSLNs are positive or when the tumor drains to PSLNs alone.

Prediction of sentinel node status and clinical outcome in a melanoma centre

Background. Sentinel lymph node biopsy (SLNB) is a standard procedure for patients with localized cutaneous melanoma. The National Comprehensive Cancer Network (NCCN) Melanoma Panel has reinforced the status of the sentinel lymph node (SLN) as an important prognostic factor for melanoma survival. We sought to identify predictive factors associated with a positive SLNB and overall survival in our population. Methods. We performed a retrospective chart review of 221 patients who have done a successful SLNB for melanoma between 2004 and 2010 at our department. Univariate and multivariate analyses were done. Results. The SLNB was positive in 48 patients (21.7%). Univariate analysis showed that male gender, increasing Breslow thickness, tumor type, and absence of tumor-infiltrating lymphocytes were significantly associated with a positive SLNB. Multivariate analysis confirmed that Breslow thickness and the absence of tumor-infiltrating lymphocytes are independently predictive of SLN metastasis. The 5-year survival rates were 53.1% for SLN positive patients and 88.2% for SLN negative patients. Breslow thickness and the SLN status independently predict overall survival. Conclusions. The risk factors for a positive SLNB are consistent with those found in the previous literature. In addition, the SLN status is a major determinant of survival, which highlights its importance in melanoma management.

Hot or not? The 10% rule in sentinel lymph node biopsy for malignant melanoma revisited

BACKGROUND

The surgeon needs a practical rule to follow when deciding whether to excise a lymph node during sentinel node biopsy (SLNB). The "10% rule" dictates that all nodes with a radiation count of greater than 10% of the hottest node and all blue nodes should be removed, and this study observes the effects of following this rule in SLNB in melanoma.

METHODS

We reviewed the records of 665 patients with primary melanoma who underwent sentinel lymph node over a 5-year period (2007-2011).

RESULTS

2064 nodes were identified in 898 nodal basins in 665 patients. 141 (21%) patients had at least one positive sentinel node. 105 positive nodal basins were identified in which more than one sentinel node was removed. In 18 of these, a less radioactive node was positive for tumour when the most radioactive node was negative. Of 175 positive nodes 157 (90%) contained blue dye staining. For cases in which the positive sentinel node was not the hottest node, the positive node had apparent blue dye staining in all 18 cases (100%), and was the second hottest node in the basin.

CONCLUSION

In this series removing just the hottest node and all blue nodes would not have missed a single positive basin and would have resulted in a 38% reduction in the number of nodes removed compared to those taken following the 10% rule, without changing the staging in any patient.

Effect of biopsy type on outcomes in the treatment of primary cutaneous melanoma

BACKGROUND

Surgical excision remains the primary and only potentially curative treatment for melanoma. Although current guidelines recommend excisional biopsy as the technique of choice for evaluating lesions suspected of being primary melanomas, other biopsy types are commonly used. We sought to determine the impact of biopsy type (excisional, shave, or punch) on outcomes in melanoma.

METHODS

A prospectively collected, institutional review board-approved database of primary clinically node-negative melanomas (stages cT1-4N0) was reviewed to determine the impact of biopsy type on T-staging accuracy, wide local excision (WLE) area (cm(2)), sentinel lymph node biopsy (SLNB) identification rates and results, tumor recurrence, and patient survival.

RESULTS

Seven hundred nine patients were diagnosed by punch biopsy (23%), shave biopsy (34%), and excisional biopsy (43%). Shave biopsy results showed significantly more positive deep margins (P < .001). Both shave and punch biopsy results showed more positive peripheral margins (P < .001) and a higher risk of finding residual tumor (with resulting tumor upstaging) in the WLE (P < .001), compared with excisional biopsy. Punch biopsy resulted in a larger mean WLE area compared with shave and excisional biopsies (P = .030), and this result was sustained on multivariate analysis. SLNB accuracy was 98.5% and was not affected by biopsy type. Similarly, biopsy type did not confer survival advantage or impact tumor recurrence; the finding of residual tumor in the WLE impacted survival on univariate but not multivariate analysis.

CONCLUSIONS

Both shave and punch biopsies demonstrated a significant risk of finding residual tumor in the WLE, with pathologic upstaging of the WLE. Punch biopsy also led to a larger mean WLE area compared with other biopsy types. However, biopsy type did not impact SLNB accuracy or results, tumor recurrence, or disease-specific survival (DSS). Punch and shave biopsies, when used appropriately, should not be discouraged for the diagnosis of melanoma.

Clinicopathologic and Survival Differences between Upper and Lower Extremity Melanomas

This analysis was performed to compare differences in clinicopathologic factors, sentinel lymph node (SLN) status, and survival between upper extremity (UE) and lower extremity (LE) melanoma patients. Post hoc analysis of a prospective clinical trial was performed of all patients with extremity melanomas with complete data. Survival was evaluated with Kaplan-Meier analysis. Univariate and multivariate analyses were performed. A total of 1115 patients aged 18 to 70 years with extremity melanomas ≥ 1.0 mm Breslow thickness were analyzed; all underwent SLN biopsy with completion lymphadenectomy for a tumor-positive SLN. Compared with UE patients, LE melanoma patients were younger, predominantly female, and had a higher rate of SLN metastasis. Kaplan-Meier analysis revealed worse 5-year disease-free survival (DFS) and worse local and in-transit recurrence-free survival in LE versus UE melanoma patients, but no difference in overall survival (OS). Subgroup analysis revealed that older patients (age > 51 years) with LE melanomas had worse DFS, local and in-transit recurrence-free-survival, and OS. LE tumor location was not an independent risk factor for OS or DFS. Compared with UE melanoma patients, those with LE melanomas have a greater risk of tumor-positive SLN and local/in-transit recurrence.

False-Negative Sentinel Lymph Node Biopsy in Head and Neck Melanoma

Objective. The results of sentinel lymph node biopsy (SLNB) can be useful for staging and deciding on adjuvant treatment for patients with head and neck melanoma. False-negative SLNB can result in treatment delay. This study aimed to evaluate the characteristics and outcome of patients with false-negative SLNB in cutaneous melanoma of the head and neck.

Study Design. Longitudinal cohort study using a prospective institutional tumor registry.

Setting. Academic health center.

Subjects and Methods. Data from 153 patients who underwent SLNB for melanoma of the head and neck were analyzed. False-negative biopsy was defined as recurrence of tumor in a previously identified negative nodal basin. Statistical analysis was performed on registry data.

Results. Positive sentinel lymph nodes were identified in 19 (12.4%) patients. False-negative SLNB was noted in 9 (5.9%) patients, with a false-negative SLNB rate of 32.1%. Using multivariate regression analysis, only examination of a single sentinel lymph node was a significant predictor of false-negative SLNB ( P = .01). The mean treatment delay for the false-negative SLNB group was 470 days compared with 23 days in the positive SLNB group ( P < .001). The 2-year overall survival of patients with false-negative SLNB was 75% compared with 84% and 98% in positive and negative SLNB groups, respectively ( P = .02).

Conclusions. False-negative SLNB is more likely to occur when a single sentinel lymph node is harvested. There is significant treatment delay in patients with false-negative SLNB. False-negative SLNB is associated with poor outcome in patients with melanoma of the head and neck.

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 node staging of cutaneous melanoma: predictors and outcomes

BACKGROUND

The authors updated their experience with sentinel lymph node (SLN) biopsy of clinically node negative (N0) melanoma to clarify indications, predictive factors, and outcomes.

METHODS

A review of patients from the authors' institution's prospective database (n = 397) was performed; survival statistics were obtained from the institutional tumor registry.

RESULTS

The SLN-positive (SLN+) rate was 16% (47 of 282) for lesions >1 mm thick; only 2 of 105 T1 lesions were SLN+. Thickness >2 mm, upper extremity primary, and ulceration predicted SLN+ status. Most SLN+ patients underwent completion node dissection; 12% had additional positive nodes. The false-negative SLN biopsy rate was 4.0%; the majority involved lower extremity and head and neck primaries. The overall complication rate was 26%; all were minor and resolved within 6 months. Overall 5-year survival rates were 73% and 92% for SLN+ and SLN-negative patients, respectively. SLN status was the most significant predictor of survival.

CONCLUSIONS

SLN status, the most important determinant of outcome for clinically N0 melanoma, correlated with T stage, ulceration, and site. Staging of T1 lesions had low yield. A minority of completion node dissections yielded additional positive nodes.

A comprehensive overview of radioguided surgery using gamma detection probe technology

The concept of radioguided surgery, which was first developed some 60 years ago, involves the use of a radiation detection probe system for the intraoperative detection of radionuclides. The use of gamma detection probe technology in radioguided surgery has tremendously expanded and has evolved into what is now considered an established discipline within the practice of surgery, revolutionizing the surgical management of many malignancies, including breast cancer, melanoma, and colorectal cancer, as well as the surgical management of parathyroid disease. The impact of radioguided surgery on the surgical management of cancer patients includes providing vital and real-time information to the surgeon regarding the location and extent of disease, as well as regarding the assessment of surgical resection margins. Additionally, it has allowed the surgeon to minimize the surgical invasiveness of many diagnostic and therapeutic procedures, while still maintaining maximum benefit to the cancer patient. In the current review, we have attempted to comprehensively evaluate the history, technical aspects, and clinical applications of radioguided surgery using gamma detection probe technology.

Utility of frozen-section analysis of sentinel lymph node biopsy specimens for melanoma in surgical decision making

BACKGROUND

Debate exists whether frozen-section analysis of sentinel lymph nodes (SLNs) for melanoma is an accurate method to detect disease that has metastasized to the lymph nodes. The purpose of this study was to evaluate the utility of intraoperative frozen section for SLNs in melanoma.

METHODS

We reviewed 133 patients (271 nodes) who underwent SLN biopsy with frozen section for melanoma between April 2003 and September 2007. Frozen-section diagnosis was compared with final diagnosis to determine concordance between intraoperative and postsurgical diagnosis.

RESULTS

A total of 11 nodes (8% of patients) were found to have metastatic disease. All patients underwent lymph node dissections at the time of SLN biopsy. No false-positive SLNs were found on frozen section. The false-negative rate for SLN biopsy frozen section was 8% (1 of 133 patients).

CONCLUSIONS

Intraoperative frozen section can be an accurate and reliable tool in the right setting for analysis of sentinel nodes in cutaneous melanoma and deserves further study.

OX40 (CD134) expression in sentinel lymph nodes correlates with prognostic features of primary melanomas

BACKGROUND

The expression of OX40 (CD134) on activated CD4+ T cells has been associated with favorable cancer patient outcomes. Because of recent reports that sentinel lymph nodes (SLNs) may represent an immunosuppressive environment, we investigated the expression of OX40 in SLNs from patients with primary cutaneous melanoma.

METHODS

Samples of peripheral blood lymphocytes and a section of 71 SLNs from 53 patients with clinically node negative melanoma were purified for CD4+ T cells, stained for OX40, and analyzed by flow cytometry.

RESULTS

The mean percentage of OX40 on CD4 T cells in the SLNs versus peripheral blood lymphocytes was related indirectly to the T stage of the primary tumor and was decreased in ulcerated primary tumors and positive sentinel nodes.

CONCLUSIONS

The expression of OX40 on CD4+ T cells in SLNs draining primary melanomas decreased with more advanced tumor features (higher T stage, ulceration) and nodal involvement, suggesting that such tumors may have an immunosuppressive effect on the SLN microenvironment.