Stopping melanoma from spreading depends on the stage at diagnosis, but the core strategy is the same: remove the primary tumor with adequate margins, check whether cancer cells have reached nearby lymph nodes, and use drug therapy when the risk of spread is significant. Each of these steps has clear, evidence-based guidelines that dramatically improve outcomes. Here’s what that looks like in practice.
Surgery: The First and Most Important Step
The primary treatment for melanoma is wide local excision, which means surgically removing the melanoma along with a border of healthy skin around it. The width of that border depends on how deep the melanoma has grown into the skin, measured in millimeters (called Breslow thickness). For melanomas less than 1 mm deep, surgeons remove a 1 cm margin of surrounding skin. For melanomas between 1 and 2 mm, the margin increases to 1 to 2 cm. For anything deeper than 2 mm, a 2 cm margin is standard across virtually every international guideline.
These margins exist because melanoma cells can extend invisibly beyond the visible edges of the tumor. Removing enough surrounding tissue significantly reduces the chance of local recurrence, which is the first step in preventing spread to other parts of the body.
Checking the Lymph Nodes
Melanoma typically spreads first to nearby lymph nodes before reaching distant organs. To catch this early, doctors perform a sentinel lymph node biopsy, a procedure that identifies and removes the first lymph node(s) where the melanoma would drain. This is recommended for melanomas at least 1 mm thick. It’s also considered for thinner melanomas (0.8 to 1.0 mm) when additional risk factors are present, such as ulceration, a high rate of dividing cells, or the patient being under 40.
The likelihood of finding cancer in the sentinel node rises steeply with tumor thickness. For thin melanomas under 0.8 mm, the rate is below 5%. For melanomas between 0.8 and 1.0 mm, it climbs to 5 to 18%. For melanomas thicker than 1 mm, roughly 30% of patients have a positive sentinel node.
If cancer is found in the sentinel node, the next question is whether to remove all remaining lymph nodes in that area. A landmark trial published in the New England Journal of Medicine found that complete lymph node removal did not improve melanoma survival rates compared to close monitoring with ultrasound. The three-year survival rate was 86% in both groups. However, removing all the nodes did cause significantly more side effects: 24% of patients who had the full surgery developed lymphedema (chronic swelling), compared to just 6% in the observation group. Because of this, many patients with a positive sentinel node are now monitored closely with imaging rather than undergoing additional surgery.
Drug Therapy After Surgery
For melanoma that has a meaningful risk of returning or spreading, drug therapy after surgery (called adjuvant therapy) can substantially lower that risk. Two main categories of drugs are used, depending on the melanoma’s genetic profile and stage.
Immunotherapy
Immunotherapy drugs work by removing the brakes that melanoma puts on your immune system, allowing your body to find and destroy remaining cancer cells. The FDA approved nivolumab for patients with completely resected Stage IIB, IIC, and Stage III melanoma. This is given as an infusion, typically for up to one year after surgery. For patients with higher-stage disease, combination immunotherapy using two checkpoint-blocking drugs together is also an option, though it comes with more side effects.
Targeted Therapy for BRAF Mutations
About 40 to 50% of melanomas carry a specific genetic mutation called BRAF V600. If your melanoma has this mutation, a combination of two targeted drugs can be used after surgery to block the growth signals that drive the cancer. In a major clinical trial, this combination reduced the risk of relapse by 53% compared to placebo. At three years, 58% of patients on the targeted therapy remained relapse-free, compared to only 39% on placebo. Your tumor will be tested for this mutation as part of standard workup.
Monitoring for Recurrence
Even after successful treatment, melanoma can return months or years later. The follow-up schedule is matched to your risk level. For early-stage disease (Stage IA to IIA), clinical exams every 3 to 12 months for five years and then annually is standard, with no routine imaging needed. For higher-stage melanoma (Stage IIB and above), exams are more frequent: every 3 to 6 months for the first two years, then every 3 to 12 months for three more years, and at least annually after that. These patients also get imaging, which can include CT scans, PET scans every 3 to 12 months, and annual brain MRIs for the first five years.
The purpose of this schedule is to catch any recurrence or new melanoma as early as possible, when it’s still treatable.
Self-Exams Between Appointments
Your own eyes are a powerful detection tool between doctor visits. A monthly skin self-exam using the ABCDE framework helps you spot concerning changes early:
- Asymmetry: one half of a mole doesn’t match the other
- Border: edges are irregular, ragged, or blurred
- Color: the mole has multiple shades of brown, black, red, white, or blue
- Diameter: larger than 6 mm (about the size of a pencil eraser), though melanomas can be smaller
- Evolving: any change in size, shape, color, or height, or new symptoms like itching, bleeding, or scabbing
Use a small ruler to measure moles and take photos to track changes over time. Check your entire body, including the scalp, between toes, and the soles of your feet. Any mole that is growing, changing color, becoming raised, or developing new symptoms warrants a prompt visit to your dermatologist. Catching a second primary melanoma or a local recurrence early can mean the difference between a simple excision and a much more complex treatment course.
Reducing Your Risk of a New Melanoma
People who have had melanoma are at significantly higher risk of developing a second one. Strict UV protection is not optional for melanoma survivors. This means wearing broad-spectrum sunscreen of SPF 30 or higher daily, choosing clothing with long sleeves and long pants when outdoors, wearing wide-brimmed hats and UV-blocking sunglasses, seeking shade during peak sun hours (roughly 10 a.m. to 4 p.m.), and never using tanning beds.
Research on melanoma survivors shows that many still fall short on protective clothing and shade-seeking, even when they’re diligent about sunscreen. All of these behaviors work together. Sunscreen alone isn’t enough, and clothing alone misses exposed areas like the face and hands. Treating UV protection as a complete system, rather than a single habit, gives you the best chance of preventing a new melanoma from developing in the first place.