Clinically relevant information from sentinel lymph node biopsies of melanoma patients

Metastatic Melanoma in Sentinel Node-Negative Patients: The Ottawa Experience

BACKGROUND

Lymph node involvement is a major independent prognostic factor for survival in patients with malignant melanoma. Sentinel lymph node biopsy (SLNB) detection of microscopic nodal melanoma has been shown to improve both 5-year survival and 5-year disease-free survival.

OBJECTIVE

To determine the rate of metastatic melanoma in SLNB-negative patients at long-term follow-up.

METHODS

Study subjects include all 152 patients who had a negative SLNB and were followed at the Ottawa Regional Cancer Centre (ORCC) between 1999 and 2004. Patients with a follow-up period less than 6 months, more than 1 primary melanoma, and metastatic melanoma at diagnosis were excluded. Age at diagnosis, sex, Breslow thickness, ulceration, mitoses, regression, Clark level, anatomical location, development of metastatic melanoma, time to detection of metastatic disease, and time to death from melanoma were studied.

RESULTS

In this retrospective study at the ORCC, 40 of 140 (28.6%) patients with a single primary melanoma developed metastatic melanoma following negative SLNB at a mean follow-up of 63 months.

CONCLUSION

The rate of metastatic melanoma following negative SLNB at long-term follow-up at the ORCC is higher than the upper limit of rates reported in the literature (6%-24%). The reason for this is multifactorial, and the long follow-up period of 5 years allowed for detection of metastatic disease at a mean of 3.9 years. Long-term prognosis may be guarded in node-negative patients with a primary cutaneous melanoma, and surveillance by a multidisciplinary team is crucial.

Sentinel lymph node biopsy followed by lymph node dissection for localised primary cutaneous melanoma

BACKGROUND

Melanoma is the leading cause of skin cancer-associated mortality. The vast majority of newly diagnosed melanomas are confined to the primary cutaneous site. Surgery represents the mainstay of melanoma treatment. Treatment strategies include wide excision of the primary tumour and sentinel lymph node biopsy (SLNB) to assess the status of the regional nodal basin(s). SLNB has become an important component of initial melanoma management providing accurate disease staging.

OBJECTIVES

To assess the effects and safety of SLNB followed by completion lymph node dissection (CLND) for the treatment of localised primary cutaneous melanoma.

SEARCH METHODS

We searched the following databases up to February 2015: the Cochrane Skin Group Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (2015, Issue 1), MEDLINE (from 1946), EMBASE (from 1974), and LILACS ((Latin American and Caribbean Health Science Information database, from 1982). We also searched the following from inception: African Index Medicus, IndMED of India, Index Medicus for the South-East Asia Region, and six trials registers. We checked the reference lists of included and excluded studies for further references to relevant randomised controlled trials (RCTs). We searched ISI Web of Science Conference Proceedings from inception to February 2015, and we scanned the abstracts of major dermatology and oncology conference proceedings up to 2015.

SELECTION CRITERIA

Two review authors independently assessed all RCTs comparing SLNB followed by CLND for the treatment of primary localised cutaneous melanoma for inclusion. Primary outcome measures were overall survival and rate of treatment complications and side effects.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted and analysed data on survival and recurrence, assessed risk of bias, and collected adverse effect information from included trials.

MAIN RESULTS

We identified and included a single eligible trial comparing SLNB with observation and published in eight different reports (from 2005 to 2014) with 2001 participants. This did not report on our first primary outcome of overall survival. The study did report on the rate of treatment complications. Our secondary outcomes of disease-specific and disease-free survival, local recurrence and distant metastases were reported. There were 1347 participants in the intermediate-thickness melanoma group and 314 in the thick melanoma group.With regard to treatment complications, short-term surgical morbidity (30 days) in 1735 participants showed no difference between SLNB and observation (risk ratio [RR] 1.11; 95% confidence interval [CI] 0.9 to 1.37) for wide excision of the tumour site but favoured observation for complications related to the regional nodal basin (RR 14.36; 95% CI 6.74 to 30.59).The study did not report the actual 10-year melanoma-specific survival rate for all included participants. Instead, melanoma-specific survival rates for each group of participants: intermediate-thickness melanoma (defined as 1.2 to 3.5 mm) and thick melanomas (defined as 3.50 mm or more) was reported.In the intermediate-thickness melanoma group there was no statistically significant difference in disease-specific survival between study groups at 10 years (81.4 ± 1.5% versus 78.3 ± 2.0%, hazard ratio [HR] 0.84; 95% CI 0.65 to 1.09). In the thick melanoma group, again there was no statistically significant difference in disease-specific survival between study groups at 10 years (58.9.3 ± 4.1% versus 64.4 ± 4.6%, HR 1.12; 95% CI 0.77 to 1.64). Combining these groups there was some heterogeneity (I² = 34%) but the total HR was not statistically significant (HR 0.92; 95% CI 0.74 to 1.14). This study failed to show any difference for its stated primary outcome.The summary estimate for disease-free survival at 10 years favoured SLNB over observation in participants with intermediate-thickness and thick melanomas (HR 0.75; 95% CI 0.63 to 0.89).With regard to the rate of local and regional recurrence as the site of first recurrence, a benefit of SLNB uniformly existed in both groups of participants with intermediate-thickness and thick melanomas (RR 0.56; 95% CI 0.45 to 0.69). This is in contrast with a uniformly unfavourable effect of SLNB with regard to the rate of distant metastases as site of first recurrence, in both groups of participants with intermediate-thickness and thick melanomas (HR 1.33; 95% CI 1.03 to 1.72).

AUTHORS' CONCLUSIONS

We contacted the trial authors querying the lack of data on overall survival which was the primary outcome of their important study. They stated "there are numerous additional analyses that have yet to be reported for the trial". We expect that overall survival data will be available in a future update of this review.Disease-free survival and rate of local and regional recurrence favoured SLNB in both groups of participants with intermediate-thickness and thick melanomas but short-term surgical morbidity was higher in the SLNB group, especially with regard to complications in the nodal basin.The evidence for the outcomes of interest in this review is of low quality due to the risk of bias and imprecision of the estimated effects. Further research may have an important impact on our estimate of the effectiveness of SLNB in managing primary localised cutaneous melanoma. Currently this evidence is not sufficient to document a benefit of SLNB when compared to observation in individuals with primary localised cutaneous melanoma.

Feasibility study on measuring selected proteins in malignant melanoma tissue by SRM quantification

Currently there are no clinically recognized molecular biomarkers for malignant melanoma (MM) for either diagnosing disease stage or measuring response to therapy. The aim of this feasibility study was to develop targeted selected reaction monitoring (SRM) assays for identifying candidate protein biomarkers in metastatic melanoma tissue lysate. In a pilot study applying the SRM assay, the tissue expression of nine selected proteins [complement 3 (C3), T-cell surface glycoprotein CD3 epsilon chain E (CD3E), dermatopontin, minichromosome maintenance complex component (MCM4), premelanosome protein (PMEL), S100 calcium binding protein A8 (S100A8), S100 calcium binding protein A13 (S100A13), transgelin-2 and S100B] was quantified in a small cohort of metastatic malignant melanoma patients. The SRM assay was developed using a TSQ Vantage triple quadrupole mass spectrometer that generated highly accurate peptide quantification. Repeated injection of internal standards spiked into matrix showed relative standard deviation (RSD) from 6% to 15%. All nine target proteins were identified in tumor lysate digests spiked with heavy peptide standards. The multiplex SRM peptide assay panel was then measured and quantified on a set of frozen MM tissue samples obtained from the Malignant Melanoma Biobank collected in Lund, Sweden. All nine proteins could be accurately quantified using the new SRM assay format. This study provides preliminary data on the heterogeneity of biomarker expression within MM patients. The S100B protein, which is clinically used as the pathology identifier of MM, was identified in 9 out of 10 MM tissue lysates. The use of the targeted SRM assay provides potential advancements in the diagnosis of MM that can aid in future assessments of disease in melanoma patients.

Surgical treatment of malignant melanoma: practical guidelines

Melanoma is currently the fifth and sixth most common solid malignancy diagnosed in men and women, respectively. Although accounting for only 4% of cases of all cutaneous malignancies, melanoma accounts for more than 75% of all deaths from skin cancer. This article discusses epidemiology and risk factors, proper biopsy technique, advanced histologic evaluation of biopsy material, assessment of tumor thickness and staging, preoperative metastatic evaluation, excision margin, treatment of regional lymph nodes, treatment of recurrence, and some special clinical situations.