In short
Superficial spreading melanoma that has reached stage III represents an advanced form of skin cancer where the disease has spread beyond the original skin site to nearby lymph nodes or surrounding tissues, requiring comprehensive treatment approaches.
What is Superficial Spreading Melanoma
Superficial spreading melanoma is the most common type of melanoma, accounting for about two-thirds of all melanoma cases in some regions. It is a potentially serious skin cancer that develops from melanocytes, which are the cells in your skin that produce melanin (the pigment that gives skin its color).
This form of melanoma gets its name from the way it typically grows. At first, the cancer cells tend to stay within the top layer of skin called the epidermis. During this early phase, known as the radial growth phase, superficial spreading melanoma spreads horizontally across the skin surface as a slowly enlarging flat patch of discolored skin. This phase can last from months to years or even decades.
Most superficial spreading melanoma develops on skin that previously appeared normal and healthy. However, about 25% develop within an existing mole, which can be a normal mole, an unusual-looking mole, or one present from birth.
Superficial spreading melanoma occurs most often at body sites that receive intense but intermittent sun exposure. In men, this type of melanoma appears most commonly on the trunk, particularly the upper back (40% of cases). In women, the legs are the most common location (also 40% of cases).
The cancer nearly always develops in people with white skin. While more common in very fair skin types, it can also occur in those who tan more easily. It is rare in people with brown or black skin. Superficial spreading melanoma affects men and women equally, with only 15% of cases occurring before age 40.
Understanding Stage III Melanoma
Stage III melanoma, also known as regional melanoma, represents an advanced form of the disease where cancer has metastasized (spread) beyond the original skin site. At this stage, the melanoma has spread to nearby lymph nodes, lymph vessels, or surrounding skin areas, but has not yet reached distant parts of the body.
Lymph nodes are small, bean-shaped structures that are part of your body's lymphatic system. This system is a vast network of tissues and organs that helps remove waste, toxins, and other unwanted materials from your body. The lymphatic system also supports your immune system by transporting infection-fighting white blood cells throughout the body.
Stage III melanoma is further divided into four subgroups based on specific characteristics. These include whether the top layer of the melanoma appears broken (called ulceration) when examined under a microscope, and how extensively the cancer has grown into the lymph nodes, lymph vessels, and nearby skin. The subgroups are labeled 3A, 3B, 3C, and 3D.
Cancer cells found between the original melanoma and nearby lymph nodes have specific names depending on their location. Micro satellite metastases are tiny amounts of cancer cells found next to the melanoma that can only be seen through a microscope. Satellite metastases are cancer cells found within 2 centimeters of the melanoma. In-transit metastases are cancer cells that have spread more than 2 centimeters away from the melanoma but have not yet reached the nearest lymph node.
Sometimes doctors find melanoma cells in the lymph nodes or nearby areas but cannot locate the original primary melanoma on the skin.
How Doctors Diagnose Stage III
To diagnose melanoma and determine its stage, your doctor first removes the abnormal area along with a small amount of surrounding skin. This procedure is called an excision biopsy. A specialist doctor called a pathologist examines the tissue sample under a microscope to look for melanoma cells and determine the stage of the cancer.
If melanoma is confirmed, your doctor will usually recommend testing to check whether cancer cells have spread to nearby lymph nodes. The most common test is called a sentinel lymph node biopsy. During this procedure, your doctor identifies and removes the first lymph node or nodes that the melanoma could have spread to. This test is typically performed at the same time as a procedure called wide local excision, which removes a larger area of tissue around the original melanoma site.
If your doctor can feel that lymph nodes near the melanoma are swollen, you will usually have an ultrasound scan instead of a sentinel lymph node biopsy. During the ultrasound, your doctor may take a sample of tissue from the lymph node to check for cancer cells.
You may also have additional scans and tests to help determine the full extent of the cancer and plan the best treatment approach.
Treatment Approaches
Surgery is the main treatment for stage III melanoma. The specific treatment plan depends on several factors, including the exact stage of the melanoma, where it is located on your body, your overall health, and your level of physical fitness.
Some people with stage III melanoma may receive other treatments in addition to surgery, or instead of surgery if the melanoma cannot be removed. These additional treatments may include chemotherapy, targeted cancer drugs, or immunotherapy.
Your doctor or specialist nurse can explain what your exact stage of melanoma means and discuss the most appropriate treatment options for your specific situation.
