SENTINEL LYMPH NODE
BIOPSY IN MELANOMA
Phoebe Prowse
SPR Plastic Surgery
Skin CNG Educational Meeting
May 19th 2010
Introduction
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The presence or absence of
lymph node metastases
remains the most powerful
predictor of outcome in
malignant melanoma.
Rationale
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Sentinelle - ‘to guard over’ or
‘vigilance’
The node(s) that has the
highest risk of harbouring
micrometastatic disease.
History of the procedure
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First described more than 50 years ago and used to stage
carcinoma of the penis.
Proposed by Morton as an alternative to elective lymph node
dissection in melanoma, in 1992.
Objective of the procedure
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To identify the 20-25% of patients who present with clinically occult
regional disease.
To minimise the morbidity associated with elective lymphadenectomy
by identifying those patients most likely to benefit.
Identifies those patients who may benefit from post-operative
adjuvant therapy.
Provides a means to stratify patients for randomised clinical trials.
Indications
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Typically recommended for
patients in whom the
estimated risk of lymph node
metastases is at least 10%.
AJCC recommendations
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•
Recommended as a staging procedure in patients whom the
information would be useful for planning subsequent treatment and
follow–up.
Specifically should be discussed with and recommended for those
otherwise fit patients with T2, T3 and T4 disease, and clinically
uninvolved lymph nodes, and selectively recommended for patients
with T1b melanomas.
Contraindications
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Palpable lymph node.
Presence of satellite lesions or
in transit metastasis.
Allergy to dye or latex.
Disruption of lymphatic
drainage, i.e. prior wide
excision.
The Head and Neck
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Drainage patterns variable
and unpredictable.
Radioactive signal from the
primary tumour may obscure
that from the SLN in nearby
nodal basin.
Localisation rate less than
95%.
Increased surgical morbidity.
Nuclear Medicine
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Patients undergo preoperative lymphoscintigraphy
and injection of radioactive
isotope around the primary
melanoma site or excisional
biopsy scar.
Identifying the Sentinel Node
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Gamma probe directs the
surgeon to the area of
greatest radioactivity.
Blue dye is used to visualise
lymphatics to help decrease
the dissection needed to
detect the SLN.
‘N’ marks the spot...
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The location of the highest
radioisotope uptake is
marked to indicate the
presence of the sentinel
node(s).
In theatre
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0.5 – 1ml of 1% isosulfan
blue is injected intradermally
around the intact tumour or
biopsy site.
The blue dye travels to the
SLN within 5-15 mins.
Wide Excision
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A wide local excision of the
primary tumour site is
performed.
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A hand held gamma probe is
used to identify hot spots in
the identified regional lymph
node basin or basins.
A small incision is made over
the hot spot.
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A blue stained afferent
lymphatic vessel is sought and
a combination of this visual
cue and the gamma probe
lead to the identification of a
hot and or blue sentinel
node(s)
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A SLN is defined as one that
localised blue dye and/or
concentrated radiolabelled
colloid within a regional nodal
basin.
Postoperative care
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Discharged the day of, or the
day after surgery.
Outpatient appointment 2
weeks to discuss results.
Complications
Overall rate less than 5%
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Failure to identify node
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Allergic reaction
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Bleeding
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Infection (1%)
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Lymphoedema (<2%)
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Seroma (2%)
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False negative result (4.7-8%)
Locoregional recurrence
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1-6% risk of isolated nodal relapse in the mapped nodal basin
after negative SLNBx (follow-up 13-60 months in 14 published
series).
Completion regional lymphadenectomy
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Offered to all patients with
positive sentinel node result.
No method to reliably predict
those patients who will have
residual metastatic disease in
other non-sentinel nodes.
70-80% have no further
disease identified.
Outcome and Prognosis
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Sentinel node status has prognostic significance with 90% 5 year
survival for SLN-negative patients versus 72% for SLN-positive
patients.
Sentinel lymph node biopsy has not been shown to increase the risk
of developing in-transit disease.
Trial Data – MSLT 1
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No overall significant survival benefit for patients randomised to
wide local excision and SLNBx with early lymph node dissection,
versus observation (86% vs. 87% at 5 years).
Disease free survival was significantly better for patients
undergoing SLNBx (78% vs. 73% at 5 years).
The Future...
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RT-PCR to improve sensitivity
of detecting occult metastatic
disease.
MSLT 2 - Completion
lymphadenectomy versus
follow-up only following a
positive sentinel node.
Conclusion
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Sentinel lymph node status has been shown to be a powerful
indicator of prognosis in patients with melanoma.
SLNBx identifies patients who may benefit from adjuvant therapy
and stratifies patients into more homogenous groups for inclusion in
clinical trials.
Improved disease free survival.
Questions..?