Newly Diagnosed With Melanoma: First Steps

Melanoma is uncommon among skin cancers and dangerous out of proportion to its numbers. The American Cancer Society projects about 112,000 new cases and 8,510 deaths in the United States for 2026. Melanoma is roughly 1% of skin cancers but causes most skin cancer deaths.

Almost every decision ahead depends on two lines in the pathology report. Get a copy before your first oncology visit.

PDQ also raises a point most people never hear. Pathologists do not always agree when telling melanoma from a benign mole. PDQ recommends review by an experienced pathologist and says a second opinion is worth considering. If your diagnosis came from a general lab, ask whether the slides can be reviewed by a dermatopathologist.

Breslow thickness. This is how deep the melanoma goes, measured in millimeters. PDQ names it as a primary prognostic factor.

Ulceration. This means the surface layer over the tumor has broken down. It is either present or absent, and its presence moves the stage up within the same thickness group.

Those two items drive the T category in AJCC staging, which runs from stage 0 to stage IV.

If your report does not state a Breslow thickness, ask why. A shave biopsy that cut through the base of the lesion can make the depth unmeasurable. That is one reason PDQ advises biopsy by local excision rather than shaving or cauterization.

The biopsy that made the diagnosis is almost never the definitive surgery. A wide local excision follows, removing a margin of normal skin around the scar.

Guideline margins are keyed to thickness:

• Melanoma in situ: 0.5 to 1 cm.
• Thickness under 1 mm: 1 cm.
• Thickness 1 to 2 mm: 1 to 2 cm.
• Thickness over 2 mm: 2 cm.

Those numbers are in centimeters, while the thickness is in millimeters. It is a large amount of skin for a small lesion, and knowing that in advance makes the surgical consult less alarming.

A sentinel lymph node biopsy identifies the first node that drains the tumor site and removes just that node. It is a staging test, done during the wide excision.

The thickness thresholds are specific:

• 0.8 mm or thicker: standard indication.
• Thinner than 0.8 mm without ulceration: generally not recommended. Exceptions exist for high-risk features such as young age, a high mitotic rate, lymphovascular invasion, or positive margins.
• 0.8 to 1.0 mm with ulceration: should be considered.

NCCN uses a threshold of about 5% probability of a positive node to decide when the procedure is not worth doing.

Ask directly whether it is being offered, and if not, why not. It is easiest to perform at the same time as the wide excision.

Melanoma is sorted by molecular subtype. PDQ cites The Cancer Genome Atlas: BRAF-altered 52%, RAS-altered 28%, NF1-altered 14%, and triple wild-type 14.5%.

BRAF status is the one that changes a treatment option. Tumors with a BRAF alteration can be treated with BRAF and MEK inhibitors, a pill-based targeted therapy. Tumors without it cannot.

PDQ notes an important asymmetry. Immunotherapy works across molecular subtypes. Targeted therapy is limited to tumors carrying the specific alteration. So a negative BRAF test does not narrow your options as much as it sounds.

Ask when BRAF testing will be done and on which tissue sample. For early-stage disease it may not be ordered right away.

Treatment intensity tracks stage.

For stage 0 through IB, PDQ describes excision with appropriate margins, plus consideration of sentinel node biopsy.

For stages II and III, surgery may be followed by adjuvant treatment, meaning treatment given after surgery to lower the chance of recurrence. That may be immunotherapy or targeted therapy.

One concrete example: FDA approved nivolumab as adjuvant treatment for completely resected stage IIB or IIC melanoma, in patients 12 years and older. The evidence was CHECKMATE-76K, which randomized 790 patients 2 to 1 against placebo. Median recurrence-free survival was not reached in either group. The hazard ratio was 0.42, with a 95% confidence interval of 0.30 to 0.59.

It is an infusion, and the clinic chooses between a two-weekly and a four-weekly rhythm, continuing for up to a year. The amount at each visit is set by the melanoma team from the label and your weight, so the part worth planning around is the visit schedule rather than any figure. Side effects reported in at least 20% of patients were fatigue, musculoskeletal pain, rash, diarrhea, and itching.

For stage III and IV disease, PDQ describes immunotherapy, BRAF and MEK inhibitors for BRAF-altered tumors, and combination approaches.

PDQ describes the ABCDE features used to spot suspicious pigmented lesions:

• Asymmetry: one half unlike the other.
• Border: edges that are irregular or poorly defined.
• Color: more than one shade within the lesion.
• Diameter: larger than 6 mm.
• Evolution: any change over time.

PDQ separately lists early warning signs: darker or uneven discoloration, itching, growth or new satellite spots nearby, and ulceration or bleeding.

Evolution matters most after a melanoma diagnosis. A spot that is changing deserves attention even if it fails every other letter.

• What is my Breslow thickness in millimeters, and is ulceration present or absent?
• What AJCC stage does that give, and was it clinical or pathologic staging?
• Were my slides reviewed by a dermatopathologist?
• What margin will the wide excision take, and can the sentinel node biopsy be done at the same operation?
• Has BRAF testing been ordered, and when will results be back?
• Is adjuvant treatment indicated for my stage, and what is the expected duration?
• How often will full skin exams happen, and who performs them?

• Call your care team right away, day or night, if you have a temperature of 100.4°F (38°C) or higher while on treatment. CDC treats fever during cancer treatment as a medical emergency. If you cannot reach the team quickly, go to an emergency department and say at once that you are on cancer treatment.
• Call 911 or go to an emergency department if an infusion brings on wheezing, a swollen tongue or lips, a spreading rash, or faintness. That is an allergic reaction and it moves fast.
• Call 911 or go to an emergency department if you develop sudden breathlessness, chest pain, severe belly pain with a rigid abdomen, a first seizure, or new one-sided weakness.
• Call your care team the same day if you are on immunotherapy and develop diarrhoea several times a day, blood or mucus in the stool, a new cough, yellowing of the eyes, or a rash that is blistering. Checkpoint drugs can inflame the bowel, lungs, liver, or glands, and these need steroids started early.
• Call your care team within a day or two if deep fatigue, dizziness on standing, or unusual thirst sets in. Those can be signs of a hormone gland affected by treatment.
• Call your care team within a day or two if a surgical site reddens, leaks, or opens, or if a mole changes, bleeds, or a new lump appears near the scar or in nearby lymph nodes.

• https://www.cancer.gov/types/skin/hp/melanoma-treatment-pdq
• https://www.ncbi.nlm.nih.gov/books/NBK572149/
• https://www.fda.gov/drugs/resources-information-approved-drugs/fda-approves-nivolumab-adjuvant-treatment-stage-iibc-melanoma
• https://www.cdc.gov/cancer-preventing-infections/patients/fever.html
• https://www.cancer.gov/about-cancer/treatment/types/immunotherapy/side-effects
• https://www.cancer.org/research/cancer-facts-statistics.html