If you have a cancerous mole, the process that follows is surprisingly systematic: a biopsy to confirm the diagnosis, surgery to remove the mole with a margin of healthy skin, and then a monitoring plan based on how deep the cancer grew. Most melanomas caught early are highly treatable, with a 5-year survival rate of 100% for localized disease. What happens next depends almost entirely on how thick the tumor is at the time of diagnosis.
The Biopsy Confirms What You’re Dealing With
A suspicious mole isn’t officially cancerous until a biopsy proves it. Your dermatologist will remove all or part of the mole and send the tissue to a pathologist, who examines it under a microscope. There are a few ways this is done.
A shave biopsy removes a thin section from the top layers of skin. A punch biopsy goes deeper, pulling a small cylinder of tissue that includes the upper fat layer beneath the skin. An excisional biopsy removes the entire mole along with a border of normal skin around it. Which type your doctor uses depends on the size, location, and how suspicious the mole looks. For a mole that’s strongly suspected to be melanoma, excisional biopsy is often preferred because it gives the pathologist the full picture of how deep the abnormal cells extend.
Thickness Determines Almost Everything
The single most important number in your pathology report is the Breslow depth, which measures how far below the skin surface the melanoma cells have reached. This measurement, given in millimeters, drives every decision that follows.
A melanoma 1 millimeter or less is classified as stage 1A. Between 1.1 and 2 millimeters without ulceration (a break in the skin over the tumor), it’s stage 1B. Thicker tumors move into stage 2 and beyond. The pathology report will also note whether the surface of the melanoma is ulcerated, whether the cells are dividing rapidly, and whether the margins of the biopsy sample are clear of cancer cells.
This information isn’t just academic. It tells your medical team how aggressively to treat the melanoma, whether to check your lymph nodes, and how closely to monitor you afterward.
Surgery to Remove the Cancer
Nearly everyone with a cancerous mole needs a procedure called wide local excision. Even if the entire mole was removed during the biopsy, surgeons go back and cut out a wider margin of healthy tissue to make sure no stray cancer cells remain at the edges.
The size of that margin depends on tumor thickness. For thinner melanomas, about 1 centimeter of surrounding skin is removed. For melanomas thicker than 2 millimeters, guidelines recommend 2-centimeter margins. This sounds like a lot, but in practice the resulting scar is often a thin line that heals well. The surgery is typically done under local anesthesia as an outpatient procedure, meaning you go home the same day.
Checking the Lymph Nodes
Melanoma cells can spread from the original mole through the lymphatic system, typically reaching nearby lymph nodes before traveling to distant organs. To find out whether this has happened, doctors may recommend a sentinel lymph node biopsy. This involves identifying the first lymph node that drains from the area of the melanoma, removing it, and checking it for cancer cells.
Not everyone needs this test. For very thin melanomas under 0.8 millimeters without ulceration, routine lymph node biopsy isn’t recommended because the risk of spread is extremely low. For melanomas between 0.8 and 1.0 millimeters, or thinner ones that are ulcerated, it becomes a conversation between you and your surgeon about whether the potential benefit justifies the procedure. For melanomas thicker than 1 millimeter, lymph node biopsy is a standard recommendation. Even for very thick tumors over 4 millimeters, the test is still useful for planning treatment, though spread is more likely at that point.
If the sentinel node comes back clear, no further lymph node surgery is needed. If cancer cells are found, your team will discuss additional treatment options.
What Happens if It Has Spread
When melanoma moves beyond the original site, treatment shifts from surgery alone to a combination approach. The most common path of spread starts with nearby lymph nodes, then potentially to distant organs. The lungs, liver, brain, and bones are frequent destinations for metastatic melanoma.
The treatment landscape for advanced melanoma has changed dramatically over the past decade. Two major categories of drugs now exist. Immunotherapy drugs work by helping your immune system recognize and attack melanoma cells that it would otherwise miss. These are given as infusions, typically every few weeks. The other category targets specific genetic mutations found in about half of all melanomas. If your tumor carries a mutation in a gene called BRAF, oral medications can block the signaling pathway that drives the cancer’s growth. These targeted therapies are often combined with a second drug that blocks a related pathway to improve effectiveness and reduce resistance.
The FDA has approved more than 20 drugs for melanoma treatment, reflecting how much research has gone into this cancer. For patients with advanced disease, these therapies can produce durable responses lasting years in some cases.
Survival Rates by Stage
The numbers here are genuinely encouraging for most people. According to the SEER database, which tracks cancer outcomes across the United States, the 5-year relative survival rate for melanoma that hasn’t spread beyond the original site is 100%. That means people with localized melanoma live just as long as people without the diagnosis.
When melanoma has spread to regional lymph nodes, the 5-year survival rate drops to 76%. For distant metastatic melanoma, it’s 34%, though this number is improving as newer treatments become more widely used. The vast majority of melanomas are caught at the localized stage, which is why early detection makes such a significant difference.
The Follow-Up Schedule After Treatment
Once your melanoma is treated, you enter a monitoring phase that can last five years or longer. The frequency of your appointments depends on the stage at diagnosis.
For stage 0 (melanoma in situ, meaning the abnormal cells haven’t grown beyond the top layer of skin), you typically need just one follow-up visit after treatment. For stage 1A, expect appointments every six months for the first year, with no routine scans needed. If everything looks clear after a year, you’re generally discharged from active follow-up.
Stage 1B and 2A melanomas call for visits every six months for the first one to two years, then annually, with possible ultrasound scans during the first three years. The monitoring window extends to five years. For stage 2B and 2C, appointments happen every three months for the first two years, shifting to every six months in year three, then annually. CT or MRI scans may be part of this schedule.
For stage 3 and 4 melanoma that was surgically removed, follow-up is most intensive: every three months for three years, then every six months for two more years, with regular imaging scans throughout. If your melanoma couldn’t be fully removed surgically, the follow-up schedule is personalized based on your specific situation and how you’re responding to treatment.
Your doctor may also want to see you more frequently if you have a higher than average risk of developing a second melanoma, if you’re pregnant, or if a recommended lymph node biopsy wasn’t performed. Throughout this entire period, monthly self-examination of your skin remains one of the most effective tools for catching any new changes early.