Sentinel lymph node biopsy in melanoma: The Oxford ten year clinical experience

Has the advent of modern adjuvant systemic therapy for melanoma rendered sentinel node biopsy unnecessary?

The prognostic value of sentinel node biopsy (SNB) is well established and SNB was therefore adopted as a requirement for pathological staging of melanomas>1 mm thick in the American Joint Committee on Cancer (AJCC) 8th edition. Consequently, a negative SNB status became an eligibility criterion for clinical trials of adjuvant systemic therapy in resected stage IIB/C melanoma. However, since the Keynote 716 trial demonstrated an improvement in relapse-free survival (RFS) in patients with Stage IIB/C melanoma, all of whom had SNB staging, some have argued that SNB is no longer required for patients with T3 and T4 primary melanomas. The rationale for omitting SNB is that these patients will be able to access adjuvant immunotherapy regardless of SNB status, avoiding the costs and potential complications of SNB. However, this argument overlooks the prognostic value of knowing a patient's nodal status and the therapeutic benefit of SNB in regional disease control. Based on extrapolation of data from multiple sources, we demonstrate that the risk of regional node-field relapse with SNB and immunotherapy for T3b and T4 melanomas is around 7-9% but is 20-27% without SNB. Similarly, the node-field recurrence rate with SNB alone is around 14% compared to around 40% with no SNB or immunotherapy. Consequently, in the absence of prospective data, we propose that the optimal management of the regional node-field for high-risk T3b and T4 primary melanomas is likely to be achieved by combining SNB and adjuvant immunotherapy for those patients who are suitable, rather than either treatment alone.

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 status is strongly predictive of survival in cutaneous melanoma: Extended follow-up of Oxford patients from 1998 to 2014

INTRODUCTION

Sentinel lymph node biopsy (SLNB) is widely used as a key investigatory tool for cutaneous melanoma, with results incorporated into the latest AJCC staging guidelines. We present the results of our extended follow-up of sentinel lymph node biopsy for melanoma over a sixteen-year period.

METHODS

Data were collected prospectively from June 1998 to December 2014 from a single tertiary skin cancer referral centre. Chi-squared analysis was used to analyse patient demographics and primary tumour pathology. Survival analysis was conducted using Cox regression models and Kaplan-Meier survival curves.

RESULTS

Over a sixteen-year period 1527 patients underwent SLNB in 1609 basins, with 2876 nodes harvested. 347 patients (23%) had a positive biopsy. The most common primary tumour sites for males was the back (32%); women had a significantly higher number of melanomas occurring on the lower and upper limbs (45% and 26% respectively) [all p < 0.0001, Chi-squared]. Mean follow-up time was 4.9 years. Patients with a positive SLNB at diagnosis were significantly more likely to die from melanoma (subhazard ratio 5.59, p = 0.000, 95% CI 3.59-8.69). Breslow thickness and ulceration were also significant predictors of melanoma-specific mortality. For patients with a primary Breslow >4.0 mm ten-year disease free survival was 52% for SLNB negative and 26% for SLNB positive patients. For Breslow thicknesses of 2.01-4 mm these values were 66% and 32% respectively.

CONCLUSIONS

Sentinel lymph node biopsy status is strongly predictive of survival across all thicknesses of primary cutaneous melanoma.

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 in early melanoma-comparison of two techniques for sentinel removal

BACKGROUND

Sentinel lymph node biopsy is an established technique for melanoma staging.

OBJECTIVE

There are no studies available comparing different techniques for the removal of sentinel lymph nodes related to safety and postsurgical complication rate.

METHODS

This is a retrospective single-center trial. We analyzed the postsurgical complications in 201 consecutive melanoma patients with ligature of lymphatic vessels by sutures (group A) and in 91 consecutive patients with occlusion of lymphatic vessels by bipolar tweezers (group B). We paid particular attention to complications related to disturbed lymphatic function, such as lymph edema, lymphatic fistula, and seroma.

RESULTS

The complication rate was 5.5 % (group A) and 9.6 % (group B) which is in the range of other published trials (p = 0.89). There was no increase of complications related to lymphatic vessels in group B, although the rate of patients with more than two sentinel lymph nodes removed was 5‑times higher than in group A.

CONCLUSIONS

Removal of sentinel lymph nodes with the use of bipolar tweezers does not increase the risk of postsurgical complications, and in particular it is not associated with a higher rate of complications related to lymphatic vessel dysfunction.

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.

A systematic review and meta-analyses of sentinel lymph node identification in breast cancer and melanoma, a plea for tracer mapping

PURPOSE

Sentinel lymph node biopsy (SLNB) has become a widely accepted staging procedure for both breast carcinoma and melanoma. The aim of our study was to systematically review different SLNB techniques and perform a meta-analysis for corresponding identification and false-negative rates.

METHODS

A systematic review of the literature on SLNB in patients with early stage breast carcinoma and melanoma was performed. Only original study groups were included. The SLN identification rate and false negative rate were pooled for patients with breast carcinoma or melanoma according to radiocolloid tracer, blue dye, indocyanine green (ICG), or a combination of a radiocolloid tracer with blue dye or ICG.

RESULTS

Between 1992 and 2012, a total of 154 studies (88 breast carcinoma and 66 melanoma) were reported that met our eligibility criteria. These studies included a total of 44,172 patients. The pooled SLN identification rate in breast carcinoma and melanoma patients using solely blue dye was 85% (range: 65-100%) and 84% (range: 59-100%), while for radiocolloid alone it was 94% (range: 67-100%) and 99% (range: 83-100%), respectively. Using a combination of radiocolloid and blue, identification rates were 95% (range 94-95%) and 98% (range: 98-98%).

CONCLUSIONS

The current meta-analysis provides data that favors the use of radiocolloid or radiocolloid combined with a blue dye for SLN identification. Performing SLNB with radiocolloid alone is the technique of choice for experienced surgeons, since blue dye has multiple disadvantages. SLNB using ICG as a fluorescent dye seems a promising technique for the near future.

Analysis of melanoma recurrence following a negative sentinel lymph node biopsy

Little attention has been paid to the characteristics and outcomes of patients who experience distant, local or regional recurrence of melanoma following a negative sentinel lymph node biopsy. This article aims to review the published literature on the topic and presents some general summaries regarding this patient population. Patients who experience a disease recurrence following a negative sentinel lymph node biopsy have a worse overall survival compared with patients with a positive sentinel lymph node biopsy. The implications and possible explanations for these findings are discussed in order to both underscore the need for in-depth investigation of local, regional or distant melanoma recurrence among patients following a true negative sentinel lymph node biopsy, as well as increased efforts to minimize the rate of false negative sentinel lymph node biopsies.