Sentinel lymph node biopsy and melanoma: 2010 update Part II

Differentiation of benign nevoid rests and metastatic melanoma in sentinel lymph node biopsy

Patients with cutaneous melanoma routinely undergo sentinel lymph node (SLN) biopsy. If this first lymph node is clear, the entire lymph node basin is very likely to be free from the metastatic disease. Lymph node analysis is therefore of great importance with respect to prognostication and further management. Various cell types, including benign nevoid rests, can mimic metastatic melanomatous cells in the SLN. There is no standardized method to differentiate naevoid rests from metastatic melanoma. Diagnosis is based on cell location, morphology and multiple immunohistochemical techniques, with no single test being completely diagnostic. We present a patient with Lentigo Maligna melanoma, who was found to have benign nevoid rests on SLN biopsy, and discuss the diagnostic tests and considerations in differentiating benign nevoid rests from metastatic melanoma.

Five-year survival in patients with nodular and superficial spreading melanomas in the US population

BACKGROUND

Although superficial spreading melanomas (SSM) are diagnosed as thinner lesions, nodular melanomas (NM) have a more rapid growth rate and are biologically more aggressive compared with other histologic subtypes.

OBJECTIVE

To determine the difference in 5-year relative survival in patients with NM and SSM at the same Breslow depth and TNM stage.

METHODS

A population-based cross-sectional analysis compared the 5-year relative survival of patients with NM and SSM using data from the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER)∗Stat software (version 8.2.1-8.3.5). Chi-square tests compared the proportions, and Kaplan-Meier method with Z-score compared 5-year relative survival.

RESULTS

For patients receiving a diagnosis between 2004 and 2009, 5-year relative survival was lower in NM compared with SSM (53.7% vs 87.3%; Z score, -41.35; P < .001). Similarly, for patients receiving a diagnosis between 2010 and 2015, 5-year relative survival was lower in NM compared with SSM (61.5% vs 89.7%; Z score, -2.7078; P < .01). Subgroup analyses showed inferior survival in NM in T1b, and survival differences remained significant after excluding patients with nodal or distant metastases.

CONCLUSIONS

Five-year relative survival is worse in NM compared with SSM especially in T1b, T2a, and T2b melanomas. Melanoma subtype should be taken into consideration when making treatment recommendations.

Clinicopathologic features correlated with paradoxical outcomes in stage IIC versus IIIA melanoma patients

Under current AJCC staging criteria, stage IIC patients paradoxically have worse outcomes than IIIA patients despite the lack of nodal metastatic disease. This study sought to identify additional clinicopathologic characteristics correlated with worse patient outcomes. Retrospective chart review of stage IIC and IIIA melanoma patients were evaluated between 1995 and 2011 with clinical follow-up through 2015. Records were reviewed for demographics, clinical characteristics, and tumor pathology. Fisher's exact test and Wilcoxon's rank-sum test were used to assess group differences. Clinicopathologic features were evaluated relative to overall survival (OS), time to distant metastases, and local/regional recurrence. Overall, 128 patients were included (45 stage IIC and 83 stage IIIA) with a median follow-up time of 5.7 years. Compared with stage IIIA patients, stage IIC patients were older, and their melanomas were more likely to be nodular, amelanotic, thicker, have higher mitotic rate, tumor lymphocytic infiltrate, no radial growth phase, and less likely to have associated precursor lesions. Stage IIC patients had shorter OS and time to distant metastases; multivariate regression revealed that older age (>55 years) and mitotic rate (>5 mitoses/mm) were independent predictors of OS. Melanomas in stage IIC disease may be biologically distinct from those that are seen in stage IIIA. While sentinel node biopsies remain the standard-of-care, these results suggest that clinicians may want to assess the clinicopathologic characteristics described above to aggressively counsel, screen for distant disease, and consider adjuvant therapy, in particular for older patients and higher mitotic rates in thicker primary tumors, regardless of nodal status.

Sentinel Node Biopsy in Young Patients with Atypical Melanocytic Tumors of the Head and Neck

Objective

To examine the diagnostic value of the sentinel lymph node biopsy in pediatric through young adult head and neck melanocytic tumors of unknown malignant potential.

Study Design

Retrospective case series.

Setting

Single academic institution.

Subjects and Methods

Demographics, histology, and outcomes were examined in 14 patients aged 4 to 24 years with head and neck melanocytic tumors of unknown malignant potential. Information on age at diagnosis, primary lesion characteristics, and sentinel lymph node biopsy were compared.

Results

Of 14 patients meeting criteria for head and neck melanocytic tumors of unknown malignant potential, 8 patients underwent sentinel lymph node biopsy (57%). Of those, 4 biopsies (50%) had positive sentinel nodes. All patients undergoing sentinel lymph node biopsy had primary lesions greater than 1 mm depth or mitotic rate of at least 1 mitosis per mm². No patients had recurrence of their primary lesion at time of follow-up.

Conclusion

Our data show a high rate of node-positive sentinel lymph node biopsy for pediatric and young adult head and neck patients with melanocytic tumors of unknown malignant potential, supporting the value of sentinel lymph node biopsy in this population.

Probabilistic issues with sentinel lymph nodes in malignant melanoma

OBJECTIVES

To address issues of probability for sentinel lymph node results in melanoma and provide details about the probabilistic nature of the numbers of sentinel nodes as well as to address how these issues relate to tumor thickness and patient outcomes.

METHODS

Analysis of the probability of observing sentinel node metastases uses the discrete exponential probability distribution to address the number of observed positive sentinel nodes. In addition, mathematical functions derived from survival analysis are used. Data are then chosen from the literature to illustrate the approach and to derive results.

RESULTS

Observations about the numbers of positive and negative sentinel nodes closely follow discrete exponential probability distributions, and the relationship between the probability of a positive sentinel node and tumor thickness follows closely a function derived from survival analysis. Sentinel node results relate to tumor thickness as well as to the total number of nodes harvested but fall short of identifying all those who eventually develop metastatic melanoma.

CONCLUSIONS

Probability analyses provide useful insight into the success and failure of the sentinel node biopsy procedure in patients with melanoma.

[Sentinel lymph node biopsy in melanoma: our experience over 8 years in a universitary hospital]

BACKGROUND

Since the introduction of sentinel lymph node biopsy, its use as a standard of care for patients with clinically node-negative cutaneous melanoma remains controversial. Our experience of sentinel lymph node biopsy for melanoma is presented and evaluated.

MATERIAL AND METHODS

A cohort study was conducted on 69 patients with a primary cutaneous melanoma and with no clinical evidence of metastasis, who had sentinel lymph node biopsy from October-2005 to December-2013. Sentinel lymph node biopsy was identified using preoperative lymphoscintigraphy and subsequent intraoperative detection with gamma probe.

RESULTS

The sentinel lymph node biopsy identification rate was 98.5%. The sentinel lymph node biopsy was positive for metastases in 23 patients (33.8%). Postoperative complications after sentinel lymph node biopsy were observed in 4.4% compared to 38% of complications in patients who had complete lymphadenectomy.

CONCLUSION

The sentinel lymph node biopsy in melanoma offers useful information about the lymphatic dissemination of melanoma and allows an approximation to the regional staging, sparing the secondary effects of lymphadenectomy. More studies with larger number of patients and long term follow-up will be necessary to confirm the validity of sentinel lymph node biopsy in melanoma patients, and especially of lymphadenectomy in patients with positive sentinel lymph node biopsy.

Breslow thickness, clark index and ulceration are associated with sentinel lymph node metastasis in melanoma patients: a cohort analysis of 612 patients

BACKGROUND

Sentinel lymph node biopsy (SLNB) is the most sensitive procedure for assessing nodal status in patients with primary melanoma.

OBJECTIVE

To evaluate the predictive ability of usual primary melanoma prognosis factors of detecting sentinel lymph node (SLN) metastasis in patients with melanoma.

PATIENTS AND METHODS

A cohort of 612 consecutive patients presenting with primary skin melanoma who underwent a SLNB was evaluated. Assessment of the determinants of SLN metastasis was based on general linear model analysis. The model performance was studied using the concordance statistic and the net reclassification index. The calibration was estimated using the Hosmer-Lemeshow test.

RESULTS

The discrimination ability did not differ significantly between Breslow thickness (0.57), Clark index (0.61), ulceration (0.57) and histological subtype (0.55). Clark index, ulceration and Breslow thickness were all significant and independent determinants of SLN metastasis. The predictive ability of the final model was 0.657.

CONCLUSION

Breslow thickness, Clark index and ulceration are independent predictors of a SLN metastasis.

Can cancer registries show whether treatment is contributing to survival increases for melanoma of the skin at a population level?

RATIONALE, AIMS AND OBJECTIVES

It is uncertain whether survival increases from melanoma recorded by some population registries include a treatment effect. The US Surveillance, Epidemiology and End Results (SEER) programme has good data quality control, large numbers of cases enabling high statistical precision and summary stage plus thickness, which we consider to be a best-case population registry scenario to investigate potential for a treatment effect. We have investigated SEER data to indicate whether survivals increases are fully attributable to earlier diagnosis and other non-treatment factors.

METHODS

Through relative survival regression, the effects of diagnostic period on 5-year excess mortality were investigated, adjusting for socio-demographic factors, lesion sub-site, histology, thickness and stage at diagnosis in 1990-2009 (n = 99 690 cases).

RESULTS

The reduction in excess mortality (95% confidence interval) between 1990-1999 and 2000-2009 was 31 (20-41)% for localised melanoma, 18 (12-22)% for regional melanoma and 3 (-5-10)% for melanomas with distant spread. Younger age was predictive of a greater percentage reduction. Treatment benefits are inferred from the higher survivals in 2000-2009 but uncertainty remains due to incomplete data to adjust for non-treatment factors and a lack of treatment data.

CONCLUSIONS

Registries should use new information systems to collect more complete data on stage, other prognostic indicators, co-morbidities and treatment, to provide more definitive and detailed information on population effects of cancer control.

Sentinel lymph node biopsy for cutaneous melanoma: a 6 years study

Background:

The aim of this study was to evaluate the results of sentinel lymph node biopsy (SLNB) in cutaneous melanoma at our institution.

Materials and Methods:

128 patients with primary cutaneous melanoma who underwent SLNB between April, 2004, and August, 2010 were studied. Univariate and multivariate analysis was performed to explore the effect of variables on mortality and sentinel node status. Survival analysis was performed using the Kaplan-Meier approach.

Results:

Positive SLNB were detected in 35 (27.3%) of 128 cases. Mean Breslow depths were 3.7 mm for SLNB positive patients and 1.99 mm for SLNB negative patients. False negative rate was 1%. The recurrence rate was 40% for positive patients and 6.5% for negative patients (odds ratio 9.7 [confidence interval 95 % 3.3-28.1]). 33 patients (29%) had an ulcerated melanoma, 12 (10.5%) in the positive group and 21 (18.5%) in the negative group. The disease recurred in a 48.5% of patients with ulcerated melanoma, but only in a 2.5% of patients with non-ulcerated melanoma. Upon multivariate analysis, only Breslow thickness (P = 0.005) demonstrate statistically significance for SLNB status. Multivariate analysis for clinicopathologic predictors of death demonstrate statistically significance for Breslow thickness (P = 0.020), ulceration (P = 0.030) and sentinel node status (P = 0.020).

Conclusions:

This study confirms that the status of the sentinel node is a strong independent prognostic factor with a higher risk of death and lower survival. Patients with ulcerated melanoma are more likely to develop recurrence, and also higher risk of death than patients with non-ulcerated melanoma.

Diagnostic utility of neural stem and progenitor cell markers nestin and SOX2 in distinguishing nodal melanocytic nevi from metastatic melanomas

Sentinel lymph node evaluation is a critical component of melanoma staging, and lymph node status provides one of the most powerful predictors of melanoma recurrence and survival. One of the well-known diagnostic pitfalls in melanoma sentinel lymph node evaluation is the presence of nodal melanocytic nevi, which has been demonstrated in up to 26% of lymphadenectomy specimens and specifically in melanoma patients. Melanocytic markers enhance the sensitivity of melanoma detection in sentinel lymph nodes. However, established markers such as anti-melan-A/MART1, S100 protein and SOX10 antibodies cannot discriminate melanoma metastasis from nodal nevi. Recent studies have demonstrated strong expression of neural stem/progenitor cell markers nestin and SOX2 in melanoma. In this study, we tested the diagnostic utility of nestin and SOX2 in differentiating metastatic melanomas from nodal nevi. Twenty-three lymph nodes with metastatic melanomas and 17 with nodal nevi were examined. Of the 23 metastatic melanomas, 18 showed diffuse and strong (3+) nestin, 4 showed rare cells with strong (3+) nestin, and one showed diffuse but faint (1+) nestin staining. Nuclear SOX2 was positive in 13 metastatic melanomas. In contrast, 15 nodal nevi showed no nestin, and 2 showed rare cells with very faint (<1+) nestin staining. SOX2 was negative in 13 nodal nevi. Overall, nestin was strongly expressed in metastatic melanomas (n=22/23; 96%), but not in nodal melanocytic nevi (n=15/17; 88%; P<0.0001). SOX2 was also expressed in metastatic melanomas (n=13/23; 57%) but not in the majority of nodal melanocytic nevi (n=13/16; 81%; P=0.02). In one lymph node harboring metastatic melan-A-negative desmoplastic melanoma, nestin and SOX2 strongly highlighted the infiltrating tumor cells, suggesting the potential clinical value of these two markers in desmoplastic melanoma lymph node biopsies. This study provides evidence that nestin and SOX2 can effectively differentiate nodal melanocytic nevi from metastatic melanomas and serve as powerful diagnostic adjuncts in melanoma staging.

Secondary review of external histopathology on cutaneous oncology patients referred for sentinel lymph node biopsy: how often does it happen and is it worth it?

BACKGROUND

We reviewed the data on external histopathology review for patients referred to our institution for sentinel lymph node biopsy (SLNB) associated with melanoma, Merkel cell carcinoma and adnexal carcinoma.

METHODS

We calculated the incidence of external histopathology review and the rate of discordance between internal and external histopathology diagnoses between January 1, 2010 and February 28, 2011. We conducted an anonymous poll of our community pathologists' experience with external histopathology review prior to SLNB. Financial charges and payments from 10 Medicare patients who underwent SLNB were obtained from our hospital's finance department.

RESULTS

Sixty-eight cases were identified (63 melanomas, 4 Merkel cell carcinomas and 1 spiradenocarcinoma). The external histopathology was reviewed as part of the patient's care in 14 of 68 cases. In 3 of 14 reviewed cases, SLNB was deemed unnecessary. Nine of eleven community pathologists reported reviewing external histopathology material in less than 11% SLNB patients in their hospitals. The average Medicare reimbursement for SLNB and secondary pathology review was $5738 and $80 respectively.

CONCLUSIONS

Our data show that review of external cutaneous histopathology diagnoses on patients referred for SLNB is uncommon in our practice area, but is cost-effective and should be required to reduce unnecessary treatment.

Preoperative ultrasound is not useful for identifying nodal metastasis in melanoma patients undergoing sentinel node biopsy: preoperative ultrasound in clinically node-negative melanoma

BACKGROUND

Sentinel lymph node biopsy (SLNB) is widely used in melanoma. Identifying nodal involvement preoperatively by high-resolution ultrasound may offer less invasive staging. This study assessed feasibility and staging results of clinically targeted ultrasound (before lymphoscintigraphy) compared to SLNB.

METHODS

From 2005 to 2009, a total of 325 patients with melanoma underwent ultrasound before SLNB. We reviewed demographics and histopathologic characteristics, then compared ultrasound and SLNB results. Sensitivity, specificity, and positive and negative predictive value were determined.

RESULTS

A total of 325 patients were included, 58% men and 42% women with a median age of 58 (range 18-86) years. A total of 471 basins were examined with ultrasound. Only six patients (1.8%) avoided SLNB by undergoing ultrasound-guided fine-needle aspiration of involved nodes, then therapeutic lymphadenectomy. Sixty-five patients (20.4%) had 69 SLNB positive nodal basins; 17 nodal basins from 15 patients with positive ultrasounds were considered truly positive. Forty-five SLNB positive basins had negative ultrasounds (falsely negative). Seven node-positive basins did not undergo ultrasound because of unpredicted drainage. A total of 253 patients with negative SLNBs had negative ultrasounds in 240 nodal basins (truly negative) but falsely positive ultrasounds occurred in 40 basins. Overall, sensitivity of ultrasound was 33.8%, specificity 85.7%, positive predictive value 36.5%, and negative predictive value 84.2%. Sensitivity and specificity improved somewhat with increasing Breslow depth. Sensitivity was highest for the neck, but specificity was highest for the groin.

CONCLUSIONS

Routine preoperative ultrasound in clinically node-negative melanoma is impractical because of its low sensitivity. Selected patients with thick or ulcerated lesions may benefit. Because of variable lymphatic drainage patterns, preoperative ultrasound without lymphoscintigraphic localization will provide incomplete evaluation in many cases.

Melanoma survival in the United States, 1992 to 2005

BACKGROUND

Population-based data on melanoma survival are important for understanding the impact of demographic and clinical factors on prognosis.

OBJECTIVE

We describe melanoma survival by age, sex, race/ethnicity, stage, depth, histology, and site.

METHODS

Using Surveillance, Epidemiology, and End Results data, we calculated unadjusted cause-specific survival up to 10 years from diagnosis for 68,495 first primary cases of melanoma diagnosed from 1992 to 2005. Cox multivariate analysis was performed for 5-year survival. Data from 1992 to 2001 were divided into 3 time periods to compare stage distribution and differences in stage-specific 5-year survival over time.

RESULTS

Melanomas that had metastasized (distant stage) or were thicker than 4.00 mm had a poor prognosis (5-year survival: 15.7% and 56.6%). The 5-year survival for men was 86.8% and for persons given the diagnosis at age 65 years or older was 83.2%, varying by stage at diagnosis. Scalp/neck melanoma had lower 5-year survival (82.6%) than other anatomic sites; unspecified/overlapping lesions had the least favorable prognosis (41.5%). Nodular and acral lentiginous melanomas had the poorest 5-year survival among histologic subtypes (69.4% and 81.2%, respectively). Survival differences by race/ethnicity were observed in the unadjusted survival, but nonsignificant in the multivariate analysis. Overall 5-year melanoma survival increased from 87.7% to 90.1% for melanomas diagnosed in 1992 through 1995 compared with 1999 through 2001, and this change was not clearly associated with a shift toward localized diagnosis.

LIMITATIONS

Prognostic factors included in revised melanoma staging guidelines were not available for all study years and were not examined.

CONCLUSIONS

Poorer survival from melanoma was observed among those given the diagnosis at late stage and older age. Improvements in survival over time have been minimal. Although newly available therapies may impact survival, prevention and early detection are relevant to melanoma-specific survival.

Guidelines of care for the management of primary cutaneous melanoma. American Academy of Dermatology

The incidence of primary cutaneous melanoma has been increasing dramatically for several decades. Melanoma accounts for the majority of skin cancer-related deaths, but treatment is nearly always curative with early detection of disease. In this update of the guidelines of care, we will discuss the treatment of patients with primary cutaneous melanoma. We will discuss biopsy techniques of a lesion clinically suspicious for melanoma and offer recommendations for the histopathologic interpretation of cutaneous melanoma. We will offer recommendations for the use of laboratory and imaging tests in the initial workup of patients with newly diagnosed melanoma and for follow-up of asymptomatic patients. With regard to treatment of primary cutaneous melanoma, we will provide recommendations for surgical margins and briefly discuss nonsurgical treatments. Finally, we will discuss the value and limitations of sentinel lymph node biopsy and offer recommendations for its use in patients with primary cutaneous melanoma.