Patient question

When is sentinel lymph node biopsy (SLNB) discussed?

Sentinel lymph node biopsy (SLNB) is a staging procedure for selected patients with invasive melanoma. It helps determine whether microscopic melanoma is present in regional lymph nodes.

Short answer: the SLNB decision depends mainly on Breslow thickness, ulceration and the clinical status of regional lymph nodes. It is not a procedure for everyone with melanoma.
Breslow-based orientation

Three decision zones

pT1a
<0.8 mm
without ulceration

Routine SLNB is generally not recommended.

Thin melanoma
0.8-1.0 mm
or additional risk features

SLNB may be discussed individually.

Invasive melanoma
≥1.0 mm
clinically negative nodes

SLNB is generally actively discussed as part of staging.

This is a simplified patient-facing orientation, not an individual indication. The complete pathology report and clinical staging remain essential.

What else influences the decision

Pathology

Breslow thickness, ulceration and other features of the primary melanoma.

Clinical nodal status

SLNB is used when there are no clinically apparent metastatic lymph nodes. A suspicious node requires a different diagnostic pathway.

What the result means

Sentinel node negative

This lowers the likelihood that regional microscopic nodal disease was present at the time of surgery, but it does not reduce recurrence risk to zero.

Sentinel node positive

This confirms regional microscopic nodal involvement, changes pathological staging and can influence subsequent surveillance and systemic-treatment decisions.

N

Positive SLNB ≠ automatic complete lymph-node dissection

Subsequent management depends on stage, current guidance and multidisciplinary review.

Why the decision should be made before the next operation

If SLNB is indicated, it is generally best planned before or at the same time as wide local excision. Major tissue rearrangement or reconstruction can alter lymphatic drainage, so the sequence should be defined in advance.

1

Pathology

Breslow + ulceration.

2

Nodal assessment

Clinically negative or suspicious?

3

SLNB decision

Before definitive surgery.

4

WLE ± SLNB

One planned surgical stage.

Practical emphasis
SLNB is primarily about accurate staging, not “removing one more node just in case”.

Its value is that the result changes what is known about stage and may change the next steps.

Detailed SLNB guideBreslow thicknessWide local excisionAfter diagnosis

This page explains how the decision is made. It does not determine an individual indication for SLNB without the complete pathology report and clinical staging.