Stages of Melanoma, Explained by a Dermatologist

In 2022, the American Cancer Society (ACS) estimated that more than 96,000 people would be diagnosed with melanoma in the United States.

Melanoma is the deadliest type of skin cancer. However, a melanoma diagnosis is not a death sentence. When melanoma is diagnosed—and how quickly it's treated—has a lot to do with a person's chances of survival and recovery.

When a healthcare provider discovers melanoma, they look at the affected tissue under a microscope to determine how much cancer is in the body. They can see whether cancerous cells have spread to other tissues or organs besides the skin. That process helps them stage the disease. 

Here's what you should know about the different stages of melanoma and what they mean for treatment and prognosis.

Stage 0 Melanoma in Situ

The earliest stage of melanoma is stage 0, also known as melanoma in situ or carcinoma in situ. "In situ" is a Latin phrase that means "in position." 

Stage 0 means that cancerous cells are present only in the epidermis—the body's most superficial layer of skin—and nowhere else.

Treatment

Treatment for stage 0 of melanoma involves a wide excision surgery. During wide excision surgery, a healthcare provider cust away the affected skin. Usually, but not always, the affected area is a mole. Then, a healthcare provider stitches and bandages the wound.

"The skin will be removed with margins," Noelani González, MD, a board-certified dermatologist at the Icahn School of Medicine at Mount Sinai, told Health. "That means that some normal skin will also be removed around the edges to make sure there aren't any cancer cells left over." A healthcare provider then looks at the removed skin under a microscope to ensure that they removed all cancerous cells with "clean" margins, added Dr. González. 

In stage 0, cancerous cells have not spread to other tissues or organs, so no further treatment is required.

Some healthcare providers may recommend treating stage 0 melanoma with the following treatments:

• Radiation therapy
• A specialized surgery called Mohs surgery
• Imiquimod cream, a drug also used to treat other types of abnormal skin growths

However, not all cancer experts agree on the use of those treatments. So, wide excision is by far the standard treatment.

Survival Rate

"[A stage 0] diagnosis has a very good prognosis," said Dr. González.

People with localized melanomas (stages 0, 1, and 2) who are treated quickly have a five-year survival rate of 97%. In other words, they are, on average, about 98.4% as likely to still be alive in five years as people who don't have those cancers.

Stage 1 Melanoma

When cancerous cells spread beyond the epidermis, the next diagnosis is stage 1. With stage 1, the tumor is no more than two millimeters thick. Also, the tumor may be ulcerated, meaning it has broken through the skin. Cancerous cells have not spread to nearby lymph nodes or organs.

Treatment

"In either case, the tumor hasn't spread to any lymph nodes or any other organs," explained Dr. González. "And treatment is generally the same as with Stage 0." 

So, a healthcare provider will remove the affected area and stitch and bandage the wound.

Once a healthcare provider looks at the tumor under a microscope, no additional treatment is needed if they have removed all cancerous cells. They will also continue to follow up with you. 

In some cases, healthcare providers will take a sample from nearby lymph nodes to ensure the melanoma hasn't spread.

Survival Rate

Like with stage 0, if caught early and treated, the five-year survival rate of stage 1 melanoma is 98.4%.

Stage 2 Melanoma

With stage 2, the tumor is about one to four millimeters thick. Also, the tumor may be ulcerated, meaning that it has broken through the skin. Like stages 0 and 1, cancerous cells have not spread to nearby lymph nodes or organs.

Treatment

Most commonly, healthcare providers use wide excision surgery to treat stage 2. A healthcare provider will remove the melanoma and a margin of skin around it. The size of the margin depends on the melanoma's thickness and location.

A healthcare provider will check the removed skin under the microscope to be sure they removed all cancerous cells. And like with stage 1, a healthcare provider may recommend a biopsy of nearby lymph nodes.

Survival Rate

Like stages 0 and 1, stage 2 means that the melanoma is still localized. Therefore, people still have a five-year survival rate of 98.4%.

Stage 3 Melanoma

Stage 3 means cancerous cells have spread to nearby lymph nodes or organs. 

"We can see that it's grown outside of the initial tumor, but there's still no evidence that it's spread to distant organs," explained Dr. González.

Depending on the size and ulceration of the affected area, healthcare providers divide a stage 3 diagnosis into stages 3a, 3b, 3c, or 3d. Those stages also depend on how much cancerous cells have spread to nearby lymph nodes or organs.

Treatment

To treat stage 3, healthcare providers often must remove more than just the original tumor. 

"The [healthcare provider] will palpate your lymph nodes, and if any are felt to be enlarged, they will likely be removed and sent for testing," said Dr. González. "This involves a much larger excision and usually leaves a significant scar."

Healthcare providers take a sample of the lymph nodes where they located the melanoma. Then, they examine the removed lymph nodes under a microscope. If they find melanoma in the lymph node sample, the healthcare provider will remove the lymph nodes in that area.

Depending on the healthcare provider's findings, they may recommend additional treatment to reduce the chances of the cancerous cells from coming back, like:

• More surgery
• Radiation
• Immunotherapy
• Experimental clinical trials

Survival Rate

Stage 3 melanoma has spread regionally but not to distant sites. So, stage 3 diagnoses have a five-year survival rate of 63.6%.

Stage 4 Melanoma

Stage 4 means a person's cancer has spread to distant lymph nodes or organs such as the lungs, brain, or liver, also known as metastatic melanoma.

Treatment

Healthcare providers often remove the original tumor and affected lymph nodes with surgery or attempt to shrink them with radiation. Depending on where the cancerous cells have spread, a healthcare provider may also treat other affected organs with surgery. 

Surgery is unlikely to cure stage 4 melanoma. So, the goal is usually to control it, prevent or relieve symptoms, and improve quality of life. Healthcare providers will try to keep cancer from growing or reduce symptoms by using the following:

• Radiation
• Immunotherapy drugs
• Targeted therapy drugs
• Drugs or vaccines used in clinical trials
• Chemotherapy

Some metastatic melanoma cancers also respond to targeted therapy drugs. Those drugs target specific proteins only found in cancerous cells. As of December 2022, those drugs haven't been shown to cure melanomas or metastatic cancer. Still, they may help people live longer and experience fewer symptoms.

Survival Rate

It's difficult to cure stage 4, so the five-year survival rate for those advanced cancers is about 22.5%.

How To Protect Yourself From Melanoma

Mostly, healthcare providers diagnose melanomas during the early, localized stages, said Dr. González. And most people treated for melanoma make a full recovery.

Don't Ignore Skin Changes

Although you may feel like waiting to schedule an appointment with a healthcare provider, if you see something different on a mole or your skin, don't wait. 

"But we do have patients that have ignored that funny-looking mole for way too long. And it's not uncommon to see cases that have metastasized to other organs," said Dr. González.

Act Quickly

Melanoma tends to be a very aggressive form of cancer, and it can progress quickly from one stage to another. 

"As soon as you see something unusual, you should get it checked out," said Dr. González. "And as soon as you get a diagnosis, you need to be on top of the appropriate treatment."

Know Your Risk Factors

Some of the most common risk factors for melanoma include:

• Ultraviolet (UV) light exposure
• Fair skin that burns easily and blonde or red hair
• Five or more blistering sunburns between ages 15–20
• More than 50 moles, atypical moles, or large moles
• A family history of melanoma

You can't modify some risk factors, like your hair color, skin color, or family history. But you can reduce UV light exposure. by avoiding tanning beds and wearing sunscreen. The American Academy of Dermatology Association recommends wearing broad-spectrum, water-resistant sunscreen with an SPF of at least 30.

Get Regular Skin Checks

Monitoring your skin for abnormal growths and changes is important for everyone, whether they are predisposed to skin cancer. 

"Going to see your board-certified dermatologist yearly and doing regular skin exams may not seem that important," noted Dr. González. "But these are the things that could save your life."

It's hard to see every area of your skin on your body. So, along with doing your checks, having a healthcare provider do a regular skin check is important.

A Quick Review

Melanoma is a serious form of skin cancer, classified into stages. Three of the five stages are treatable, with good recovery and survival rates. 

Early diagnosis and treatment help improve melanoma prognosis. See a healthcare provider immediately if you notice any changes to your skin or moles. Scheduling an annual skin check with a dermatologist or healthcare provider as part of your regular healthcare can also help.