The short answer
Melanoma decisions are built on one measurement, the Breslow thickness in millimeters. It guides the surgical margin and the 0.8 mm line for node sampling, and NCI says ultrasound watching of the nodes has widely replaced removing them all after a positive sentinel node.
Breslow thickness, the depth of the melanoma in millimeters, is more reproducible than the older Clark level and should always be reported.
Localized melanoma is removed with margins proportional to the microstage of the lesion.
NCI recommends sentinel lymph node biopsy for primary tumors at least 0.8 mm thick when the nodes feel normal, and it may also apply to thinner ulcerated ones.
After micrometastasis is found in a sentinel node, NCI says active surveillance with ultrasound is acceptable and has widely replaced complete node dissection.
On this page
Choose how you want to read this
The whole article, with every detail and caution.
This page is for people with melanoma, a type of skin cancer, and the people helping them. It explains the key numbers behind treatment choices and lists questions to take to your care team.
Start with the thickness on your report
Melanoma decisions are built on one measurement. NCI calls it the Breslow thickness, the depth of the melanoma in millimeters.
NCI says it is more reproducible than the older Clark level and predicts behavior better in lesions thicker than 1.5 mm. NCI says it should always be reported.
Ask for the number. Ask whether the report says ulcerated.
How wide the surgery goes
NCI describes surgical excision as the main treatment for melanoma that has not spread. It says localized melanoma is removed with margins proportional to the microstage of the lesion. Microstage means how deep and how advanced the tumor looks under the microscope.
Ask what margin is planned for you, and whether a graft or flap will be needed.
The 0.8 mm threshold for node sampling
NCI is specific here. A sentinel lymph node biopsy removes the first one or few lymph nodes that the tumor drains into, to check them for cancer. It should be considered for primary tumors at least 0.8 mm thick, when the nodes feel normal.
It adds that thin melanomas under 0.8 mm that are ulcerated may also warrant it, especially with other bad features.
Ask whether you cross that line, and what a positive node would change.
If a sentinel node is positive
Removing all the nodes was once the usual next step. If micrometastatic melanoma is found, NCI says active surveillance with ultrasound of the nearby node area is an acceptable approach that has widely replaced complete node dissection.
Ask which approach your team recommends and why. Ask what swelling (lymphedema) risk comes with each.
Treatment after surgery
Adjuvant treatment is extra treatment after surgery to lower the chance the cancer comes back. NCI says adjuvant options for people at high risk of recurrence after complete removal include checkpoint inhibitors and combination targeted therapy.
It notes that stage IIB and IIC melanoma carries a recurrence risk similar to stage III, which supports considering adjuvant treatment.
NCI's patient page also lists pembrolizumab before surgery (neoadjuvant) as an option for stage III melanoma. In the SWOG S1801 trial, at a median follow-up of 15 months, the event-free survival rate was 72% with neoadjuvant immunotherapy and 49% with adjuvant therapy.
Questions to ask before surgery
- What is my Breslow thickness, and is my melanoma ulcerated?
- How wide a margin are you taking, and will I need a graft?
- Do I need a sentinel lymph node biopsy?
- If a node has micrometastasis, will you remove the rest or watch them with ultrasound?
- Has my tumor been tested for BRAF changes? NCI notes targeted drugs for these changes need an FDA-approved test.
- Am I stage IIB or IIC, and does adjuvant treatment apply to me?
- Is treatment before surgery an option in my case?
Ask about trials early
NCI says clinical trials remain an important option for people with melanoma, and that new agents and combinations keep emerging.
Ask what is open where you are treated.
Related pages
Next: Cancer Staging, Biomarker Testing, Clinical Trial vs Standard Treatment, and Questions to Ask Your Doctor.
Where this comes from
Common questions
Which number on my pathology report matters most?
The Breslow thickness, the depth in millimeters. Ask for that number and whether the report says ulcerated. Margin width and node sampling both follow from it.
Do I need a sentinel lymph node biopsy?
NCI recommends it for tumors at least 0.8 mm thick when the nodes feel normal, and thinner ulcerated melanomas may also warrant it. Ask what a positive node would change.
If a node is positive, will the rest be removed?
Not automatically. NCI says active surveillance with ultrasound of the nearby nodes is acceptable and has widely replaced complete node dissection. Ask which approach your team recommends.
Should I ask about a clinical trial early?
It is reasonable to ask. NCI says clinical trials remain an important option for people with melanoma, and new agents and combinations keep emerging.
Questions to ask your doctor
Being prepared helps you get the most out of your appointments. Save or print these questions.
Tap a question to save it to your list (kept on this device).
Your next step
Turn this topic into questions for your next appointment.
Talk with a trained specialist or navigator
Cancer Explained provides educational guidance, but does not replace trained specialists, social workers, or your medical team.
Talk to a trained cancer information specialist
Free, confidential assistance from NCI Cancer Information Service via phone, chat, or email.
Contact your oncology team
Locate after-hours contact numbers, portal messages, or urgent triage phone lines.
Find a patient navigator
Get one-on-one help with appointments, logistics, translation, and care coordination.
Find a genetic counselor
Discuss inherited mutation risk, family history, and genetic testing options.
Find an oncology social worker
Access emotional counseling, family support groups, and mental health resources.
Find a financial navigator
Locate copay assistance foundations, grant programs, and lodging/travel support.
Find a clinical-trial specialist
Search matching studies and speak with NCI trial information specialists.
Get urgent help
Fever of 100.4°F (38°C) or higher during chemo, severe pain, or trouble breathing: call your cancer care team right away, day or night. Call 911 for an emergency.
Know someone who needs this?
Plenty of people are looking for something like this and do not know where to start. If this would help a friend or someone you love, send it on — we have written an opening line so you do not have to stare at an empty message. You can change every word of it.
Your message is written and sent in your own email or messaging app — we never see who you send it to, and nothing is added to any list.
Plain-language explanation of the published sources cited on this page. AI-assisted, source-checked, not clinician-reviewed.
Sources last checked: 2026-07-30 what this meansLast updated: 2026-08-16Next planned review: 2027-07-30
Review details and limits
Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes, and this is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status — Source checked. This page was written with AI assistance and then compared with the sources listed on it, looking for statements those sources do not back up. That check is not a sentence-by-sentence record and can miss errors. It is not a medical review, and it does not confirm the page is complete or right for your situation.
General education — varies by person. Answers genuinely differ between people. This page explains what commonly varies and points you to your care team for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
Words to know
Tap any term to see what it means.
How this page was created
Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes, and this is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Source checked — This page was written with AI assistance and then compared with the sources listed on it, looking for statements those sources do not back up. That check is not a sentence-by-sentence record and can miss errors. It is not a medical review, and it does not confirm the page is complete or right for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
Read more about our editorial process, our use of AI, and our corrections policy.
Spotted a problem? Report an error — a factual mistake, broken or outdated source, confusing wording, or anything that seems unsafe. Please do not include names, medical record numbers, dates of birth, addresses, or other identifying medical information in your report.
After using this page, do you understand what to do next?
Anonymous — we only record the answer, never who gave it.