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Purpose and principlesIndications, selection and cautionsAssessment before treatmentTreatment approachComplications, monitoring and follow-upSpecial situationsCommon pitfallsQuestionsSources
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Educational draft · awaiting clinical reviewThe full textbook explains uncertainty but does not replace live national or local guidance, specialist advice, or current prescribing information.

Excision margins, sentinel-node and follow-up concepts

Dermatology · UK scope · Sources checked 27 Aug 2026 · Clinical review pending

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Purpose and principles

Explain the sequence from diagnostic melanoma excision to stage-based wide local excision, select sentinel-node discussion using current NICE criteria, and design follow-up around recurrence risk, skin surveillance and patient support.

Separate diagnosis, local control and regional staging. The initial narrow full-thickness excision supplies Breslow depth and ulceration. The specialist multidisciplinary team then assigns pathological stage, plans a wider clinical margin around the scar and decides whether sentinel-node staging or imaging is relevant. Presenting all three as one operation obscures why the sequence matters.

A wider margin removes microscopic local extension but does not compensate for a transected diagnostic biopsy. Stage 0 remains epidermal and uses at least 0.5 cm; stage I uses 1 cm; stage II uses 2 cm unless morbidity makes 1 cm the shared alternative. Site, reconstruction and function require plastic, head-and-neck, hand or other specialist input but should not silently reduce oncological planning.

SLNB maps lymphatic drainage with tracer and removes the first node or nodes for histology. Explain possible seroma, infection, sensory change, lymphoedema and false-negative results. It provides prognosis and access to stage-specific adjuvant discussions but is optional after informed conversation. Pregnancy can justify delaying SLNB until after completion, as NICE advises discussing.

Follow-up is not only a scan schedule. Clinical examination, self-awareness, sun protection, new-primary risk, treatment toxicity, fertility, work, anxiety and rapid symptom access all matter. Imaging is stage directed because repeated scans can detect recurrence but also create radiation, incidental findings and distress. Provide a written personalised plan and the route back between appointments.

Key points

  • Diagnostic excision removes the suspicious lesion completely with a narrow margin to establish melanoma diagnosis, Breslow depth, ulceration and pathological stage.
  • Wide local excision is a second procedure around the biopsy scar; its clinical margin is determined by stage and includes the initial primary-lesion margin.
  • NICE advises at least 0.5 cm for stage 0, 1 cm for stage I and 2 cm for stage II, using 1 cm if a 2 cm margin would cause unacceptable disfigurement or morbidity.
  • Sentinel lymph-node biopsy is a staging procedure for clinically node-negative melanoma; it does not treat the primary lesion and has not itself been shown to improve survival.
  • Do not offer imaging or SLNB for stage IA melanoma and do not perform routine imaging before SLNB unless nodal or distant metastasis is suspected.
  • Consider SLNB for Breslow 0.8–1.0 mm with ulceration, lymphovascular invasion or mitotic index 2 or more, and for Breslow thickness over 1.0 mm.
  • A positive sentinel node changes pathological stage and adjuvant-treatment discussion; routine completion lymph-node dissection is not automatic.
  • Follow-up intensity is stage based and includes whole-skin, scar, in-transit and nodal examination, self-examination education, psychosocial support and rapid re-entry for symptoms.

Indications, selection and cautions

Biopsy scar as excision centre

Wide-excision measurement surrounds the complete diagnostic scar and accounts for the margin already taken around the primary lesion.

Clinically node-negative state

SLNB applies when no nodal metastasis is detected clinically or on indicated assessment and microscopic staging remains relevant.

In-transit recurrenceRed flag

A new dermal or subcutaneous nodule between the primary scar and draining nodal basin can represent lymphatic melanoma spread.

Regional-node recurrenceRed flag

A firm enlarging node in the expected basin requires urgent ultrasound and tissue diagnosis rather than observation.

Distant-recurrence symptomRed flag

New focal neurology, persistent headache, bone pain, breathlessness or constitutional decline needs stage-aware urgent investigation.

Red flags requiring action

  • A new scar nodule, in-transit dermal lesion, firm regional node, persistent focal pain, neurological deficit, unexplained weight loss or respiratory symptoms after melanoma requires urgent specialist reassessment rather than waiting for routine follow-up.

Assessment before treatment

  1. 01
    Complete diagnostic histopathologyFirst step
    Why
    Provide Breslow thickness, ulceration, margins and adverse features before definitive planning.
    Interpretation and limitations
    If the deep margin is transected, true depth may be underestimated and the multidisciplinary team must plan further staging cautiously.
  2. 02
    Sentinel lymph-node biopsy
    Why
    Detect clinically occult regional nodal metastasis and refine pathological stage and prognosis.
    Interpretation and limitations
    Consider at 0.8–1.0 mm with specified adverse features and over 1.0 mm; do not offer for stage IA.
  3. 03
    Sentinel-node histopathology
    Why
    Determine whether microscopic melanoma is present and quantify burden for stage and adjuvant decisions.
    Interpretation and limitations
    A positive result does not automatically require completion node dissection; specialist ultrasound surveillance and systemic options are considered.
  4. 04
    Stage-directed CT, MRI or PET-CT
    Why
    Assess regional or distant disease when stage or symptoms justify imaging.
    Interpretation and limitations
    Do not image routinely before SLNB without suspected metastasis; modality and interval follow current NICE stage recommendations.

Treatment approach

01After diagnostic excisionConvert histology into local controlFirst stepA completely sampled primary lesion is confirmed as stage 0, I or II melanoma.+
  1. 1Review Breslow depth, ulceration, biopsy margins and stage in the specialist skin-cancer multidisciplinary team.
  2. 2AlternativePlan wide local excision around the histological scar using at least 0.5 cm for stage 0, 1 cm for stage I and 2 cm for stage II unless morbidity dictates the NICE alternative.
  3. 3Coordinate reconstruction and verify final margins, preserving function without losing the intended oncological field.
02Sentinel-node decisionOffer informed staging selectivelyClinically node-negative invasive melanoma falls within a NICE SLNB consideration group.+
  1. 1Do not offer SLNB for stage IA; consider it for 0.8–1.0 mm with ulceration, lymphovascular invasion or mitotic index at least 2, and over 1.0 mm.

Complications, monitoring and follow-up

  • Confirm final wide-excision histological margins and resolve any involved margin in the multidisciplinary team.
  • After SLNB monitor wound, seroma, infection, sensory change and limb or basin swelling and communicate pathology promptly.
  • At every follow-up document scar, in-transit skin, regional nodes and a complete skin examination plus patient-reported symptoms.
  • Track stage-directed imaging completion and incidental findings through a named clinician to avoid orphaned results.
  • Screen for anxiety, fear of recurrence, lymphoedema, work and financial impact and provide melanoma support and rehabilitation routes.

Special situations

Margins answer different questions

Narrow biopsy establishes diagnosis and thickness; wider re-excision reduces local recurrence after stage is known.

Sentinel means first draining

Tracer identifies the initial nodal destination, which may not be the basin predicted from surface anatomy alone.

Staging is not therapy

A negative SLNB does not treat the primary, while a positive SLNB mainly changes stage and subsequent options.

Follow-up includes new primaries

Surveillance searches not only for recurrence but also another independently arising melanoma or keratinocyte cancer.

Rapid access protects intervals

A perfect routine schedule fails if a new node must wait months for the next booked appointment.

Common pitfalls

  1. 01

    Using the narrow diagnostic margin as definitive wide-excision treatment for invasive melanoma.

  2. 02

    Offering SLNB to stage IA melanoma contrary to NICE guidance.

  3. 03

    Describing sentinel-node biopsy as a treatment guaranteed to improve survival.

  4. 04

    Ordering routine pre-SLNB imaging without clinical suspicion of metastasis.

  5. 05

    Providing scheduled follow-up without a route for urgent assessment between appointments.

Practice

Two practice questions

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Question 1 of 2
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DermatologyOriginal SBA

Wide margin for stage II melanoma

A stage II melanoma has been removed diagnostically and a 2 cm margin would not cause unacceptable morbidity. What clinical margin does NICE recommend for wide local excision?

Choose one answer, then submit
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Sources and review status3 sources · checked 27 Aug 2026 · clinical review pending+
Sources

Sources and review status

National guidance is shown before implementation-dependent detail. Apply principles in context and verify current guidance when a decision affects care. Source check completed 27 Aug 2026; clinical approval remains outstanding.

  • NICE NG14 melanoma assessment and managementCurrent excision margins, SLNB eligibility, imaging and follow-up.
  • NHS melanoma skin cancerPatient-centred surgery, node and follow-up explanation.
  • NICE melanoma information for the publicAccessible explanation of melanoma assessment, treatment and follow-up.

Editorial contact: Doctor’s Passport editorial team. Source-check date is separate from clinical approval. Report a content problem · Content changes

Authoring stateComplete draftClinical stateAwaiting reviewJurisdictionUnited Kingdom
  • 05
    Follow-up skin and node examination
    Why
    Detect local recurrence, in-transit disease, nodal spread and new primary melanoma.
    Interpretation and limitations
    Examine scar, intervening lymphatic skin, basin and full skin; patient-reported evolution can prompt biopsy between scheduled visits.
  • 2Explain prognostic and adjuvant-treatment value, lack of direct primary treatment, false negatives and surgical adverse effects, then respect informed choice.
  • 3Use the result to refine stage and specialist treatment or ultrasound surveillance without automatic completion node dissection.
    • 03Risk-stratified follow-upCombine surveillance and rapid accessDefinitiveDefinitive primary treatment and staging are complete.+
    1. 1Provide a written stage-specific schedule for clinic and imaging where NICE recommends it, including who owns each result.
    2. 2At visits examine full skin, scar, in-transit pathway and nodes and address treatment toxicity, lymphoedema, mental health and function.
    3. 3Teach monthly self-examination and give an urgent contact route for new lesions, scar nodules, nodes or organ symptoms rather than waiting for the next appointment.