Education and decision-support only — not a medical device or personalised advice. Always discuss your specific situation with your specialist team.
If you have recently been told that a mole or skin lesion is melanoma, you are likely to be Stage I or Stage II — meaning the cancer is confined to the skin with no confirmed spread to lymph nodes or distant organs. The good news: Stage I and II melanoma caught early is highly treatable, and most patients with Stage I disease are cured by surgery alone.
This article explains what happens next — the key decisions, tests, and treatments your team may discuss with you.
Step 1: Understanding your pathology report
When the melanoma is removed, a pathologist examines it and produces a pathology report. The numbers in this report determine your stage and guide next steps. Ask your doctor to explain:
- Breslow depth — how deep the melanoma grew into the skin (in millimetres). Thinner tumours (under 1 mm) have a better prognosis.
- Ulceration — whether the surface of the melanoma was broken. Ulceration increases the stage.
- Mitotic rate — how fast the cells were dividing.
- Margins — whether the melanoma was completely removed with clear edges, or whether tumour cells were found close to or at the edge of the excision.
The pathology report feeds into the AJCC 8th Edition staging system [1], which your team uses to classify your melanoma as Stage I, IIA, IIB, or IIC.
Step 2: Wide local excision (WLE) — getting clear margins
If your initial excision did not achieve clear margins (or if the surgeon took only a small biopsy to begin with), you will need a wide local excision (WLE): a further operation to remove more tissue around the melanoma site. The margin width (how far beyond the original tumour to cut) depends on Breslow depth:
| Breslow depth | Recommended excision margin |
|---|---|
| In situ (Stage 0) | 5 mm |
| ≤ 1 mm (Stage I) | 1 cm |
| 1.01–2 mm | 1–2 cm |
| > 2 mm (Stage IIA–IIC) | 2 cm |
This is minor day-surgery in most cases. Once clear margins are confirmed, surgery is complete for localised disease.
Step 3: Sentinel lymph node biopsy (SLNB) — should you have one?
The sentinel lymph node biopsy (SLNB) is a minimally invasive procedure that maps and samples the first lymph node that drains from the melanoma site. If melanoma cells are found there, it upstages the diagnosis to Stage III and guides further treatment.
Who is it recommended for?
SLNB is generally offered to patients whose melanoma is ≥ 0.8 mm deep (T1b–T3), or thinner melanomas with certain high-risk features (ulceration, high mitotic rate). For very thin Stage I melanomas (T1a, < 0.8 mm, no ulceration), the risk of lymph node involvement is low and SLNB is usually not needed.
What does it tell you?
- If the sentinel node is negative: the melanoma has not been detected in the regional nodes, and surveillance continues with no further surgery required.
- If the sentinel node is positive: this upstages to Stage III, and you will be offered further discussion about completion lymph node dissection (now less common) or adjuvant systemic therapy.
The MSLT-I Phase 3 trial confirmed that SLNB provides important prognostic information and improves disease-free survival when combined with early adjuvant treatment in node-positive patients [2].
Risks of SLNB: The procedure is generally safe. The main risks are lymphoedema (swelling, ~3–5% depending on site), wound infection, and numbness. Discuss these with your surgeon.
Step 4: Adjuvant therapy for Stage IIB and IIC
For most Stage I patients and many Stage IIA patients, surgery alone is curative and no further treatment is needed beyond surveillance. However, Stage IIB (Breslow depth 2.01–4 mm with ulceration, or > 4 mm without ulceration) and Stage IIC (> 4 mm with ulceration) carry a higher risk of recurrence — comparable to or exceeding some Stage III disease.
Pembrolizumab (Keytruda) — approved adjuvant therapy for Stage IIB/IIC
Pembrolizumab is an anti-PD-1 immunotherapy drug. The KEYNOTE-716 Phase 3 trial enrolled 976 adults with resected Stage IIB or IIC melanoma and randomly assigned them to pembrolizumab or placebo for up to 1 year [3].
Results at 2-year follow-up [4]:
| Outcome | Pembrolizumab | Placebo |
|---|---|---|
| Recurrence-free survival at 2 years | 81.2% | 72.8% |
| Hazard ratio for recurrence or death | 0.64 (95% CI 0.50–0.84) |
In other words: patients receiving pembrolizumab were 36% less likely to experience recurrence or death at any given time point, compared with placebo. FDA-approved in December 2021 for this indication.
Who should consider it? All patients with resected Stage IIB or IIC melanoma (negative sentinel node) should discuss adjuvant pembrolizumab with their oncologist. Key considerations:
- It is given intravenously once every 6 weeks for up to 1 year.
- Side effects are immune-related and similar to those for advanced melanoma immunotherapy (fatigue, thyroid problems, rash, colitis — most are manageable).
- BRAF status does not affect eligibility (pembrolizumab works regardless of BRAF mutation status).
For BRAF-mutated Stage IIB/IIC patients, dabrafenib + trametinib (targeted therapy) may be an alternative — discuss with your oncologist.
Step 5: Surveillance — what follow-up looks like
Once treatment is complete, you will enter a structured follow-up programme. Typical elements include:
- Clinical skin examination + dermoscopy — at your dermatologist or oncologist's clinic; frequency varies (often every 3–6 months for years 1–3, then annually).
- Regional lymph node examination — palpation at each visit; imaging if a node feels enlarged.
- Imaging — CT chest/abdomen/pelvis and/or whole-body PET-CT, especially for Stage IIB/IIC or SLNB-positive patients. Frequency and duration are guided by your centre's protocol.
- Self-examination — you will be taught how to check your own skin and regional lymph node regions between appointments. Report any new or changing lesion promptly.
How long? Most guidelines recommend at least 5 years of structured follow-up, with annual dermatology review continued beyond that.
Questions to ask your specialist
Bring this list to your next appointment:
- What is my exact AJCC 8th edition stage? (T category, N category, M category — and what each means for my prognosis)
- Are my surgical margins clear? If not, what is the plan for re-excision?
- Should I have a sentinel lymph node biopsy? Based on my Breslow depth and tumour features, what is the risk that my sentinel node would be positive?
- Do I qualify for adjuvant pembrolizumab? If I am Stage IIB or IIC, should I start pembrolizumab after surgery?
- What is my BRAF mutation status? Has this been tested from my tumour sample?
- Is there a clinical trial I should consider before starting any systemic treatment? See our Clinical Trial Finder.
- What does my surveillance schedule look like? How often will I have imaging, skin checks, and blood tests?
- What symptoms should make me contact the team urgently? (new lump, unexplained weight loss, headaches)
See our Getting specialist care section for guidance on accessing a melanoma MDT or requesting a specialist referral.
References
[1] Gershenwald JE, Scolyer RA, Hess KR et al. Melanoma staging: Evidence-based changes in the American Joint Committee on Cancer 8th Edition Cancer Staging Manual. CA Cancer J Clin. 2017;67(6):472–492. PMID 28961944
[2] Morton DL, Thompson JF, Cochran AJ et al. Final trial report of sentinel-node biopsy versus nodal observation in melanoma (MSLT-I). N Engl J Med. 2014;370(7):599–609. PMID 24755012
[3] Luke JJ, Rutkowski P, Queirolo P et al. Pembrolizumab versus placebo as adjuvant therapy in completely resected stage IIB or IIC melanoma (KEYNOTE-716): a randomised, double-blind, phase 3 trial. Lancet. 2022;399(10336):1718–1729. PMID 35367007
[4] Luke JJ, Ascierto PA, Khattak MA et al. KEYNOTE-716 2-year overall survival update in resected stage IIB/IIC melanoma. Lancet Oncol. 2023;24(6):618–628. PMID 37079741
Education and decision-support only — not a medical device. Does not diagnose, screen, predict, or provide personalised medical advice. Discuss all treatment decisions with your specialist team.