A spot can look small on the surface while behaving very differently beneath the skin. So, can skin cancer spread? Yes – some skin cancers can grow into nearby tissue or travel to other parts of the body. But the risk varies greatly by cancer type, how early it is found, and whether it has had time to grow deeper.

That is why a changing mole, a sore that will not heal, or a new unusual mark deserves prompt clinical assessment. Most skin cancers can be treated very effectively when detected early. Waiting to see whether a suspicious lesion settles can allow a treatable problem to become more complex.

Can skin cancer spread to other parts of the body?

Skin cancer can spread in two main ways. It may grow locally into the surrounding skin and deeper structures, such as nerves, cartilage, muscle or bone. This is called local invasion. Some cancers can also spread beyond the original site through lymphatic channels or the bloodstream. This is known as metastasis.

When skin cancer spreads, it may first reach nearby lymph nodes, which are small immune-system glands found in areas such as the neck, armpits and groin. From there, certain cancers can spread to organs including the lungs, liver, brain or bones.

Spread is not inevitable. In fact, many skin cancers are removed before they have the opportunity to move beyond the skin. The key factor is timely diagnosis. Knowledge can save your life, but it needs to lead to action.

Which types of skin cancer are most likely to spread?

Melanoma

Melanoma is less common than other major skin cancers, but it is the type most associated with spread to other parts of the body. It develops from melanocytes, the cells that give skin its pigment. Melanoma can appear as a changing mole, but it can also begin as a new spot and may occur on skin that receives little sun exposure.

The chance of melanoma spreading depends on features identified after the lesion is removed and examined in a laboratory. One of the most significant is thickness: generally, the deeper a melanoma has grown into the skin, the higher the risk that cancer cells have reached lymph nodes or elsewhere. Ulceration, growth rate and whether cancer is found in nearby lymph nodes also affect staging and treatment decisions.

This does not mean every melanoma has spread by the time it is noticed. Early melanoma, including melanoma in situ that is confined to the top layer of skin, is highly treatable with appropriate removal. The reason clinicians treat suspicious pigmented lesions seriously is that melanoma can become dangerous if diagnosis is delayed.

Squamous cell carcinoma

Cutaneous squamous cell carcinoma, often called SCC, usually develops on areas with cumulative sun exposure, including the face, ears, scalp, neck, hands and lower legs. It may look like a persistent scaly patch, thickened crust, tender lump or sore that bleeds and fails to heal.

Most SCCs are treated successfully, particularly when found early. However, SCC can invade locally and, in a smaller number of cases, spread to lymph nodes or other organs. Risk is higher for larger, deeper or rapidly growing tumours, lesions on high-risk areas such as the ear or lip, recurrent cancers, and cancers in people with weakened immune systems.

Basal cell carcinoma

Basal cell carcinoma, or BCC, is the most common skin cancer in Australia. It often appears as a pearly or shiny bump, a recurring bleeding sore, or a scaly patch that does not clear. BCC almost never spreads to distant parts of the body.

That does not make it harmless. An untreated BCC can grow steadily into nearby tissue and cause substantial damage, especially around the nose, eyelids, ears or lips. Earlier treatment usually means a smaller procedure and a better chance of preserving function and appearance.

Rarer skin cancers

There are several less common skin cancers, including Merkel cell carcinoma, dermatofibrosarcoma protuberans and some cancers affecting the lips, nails or genital skin. Their behaviour varies, and some can spread early. Any unfamiliar, changing or persistent lesion should be assessed rather than self-diagnosed from an image online.

Signs that may suggest skin cancer has progressed

A skin cancer cannot be staged by appearance alone. Only a clinician, supported by a biopsy and other tests where needed, can determine whether it has spread. Still, some changes warrant urgent review.

Contact a GP or skin cancer clinic promptly if you notice a mole or spot that is changing in size, shape, colour or sensation; a lesion that bleeds, crusts or does not heal; a firm new lump close to a known skin cancer; or unexplained swelling in lymph nodes, particularly in the neck, armpit or groin.

For melanoma, the ABCDE guide can help people identify concerning changes: asymmetry, irregular borders, varied colour, a diameter that is increasing, and evolution or change over time. The “ugly duckling” sign matters too. A spot that looks noticeably different from your other moles is worth checking, even if it does not meet every ABCDE feature.

Symptoms such as persistent unexplained headaches, breathlessness, bone pain, weight loss or fatigue have many possible causes and do not automatically mean cancer has spread. But if you have had skin cancer and develop ongoing symptoms, discuss them with your doctor rather than dismissing them.

How doctors check whether skin cancer has spread

The first step is a thorough skin examination. A doctor may use a dermatoscope, a handheld instrument that helps them examine structures beneath the skin’s surface. If a lesion is suspicious, they may remove it completely or take a biopsy for laboratory analysis.

The pathology report provides crucial information. For melanoma, it can show the thickness of the tumour, whether there is ulceration and whether it has been fully removed. For higher-risk melanoma or SCC, further assessment may include an examination of nearby lymph nodes, imaging scans or referral to a specialist team.

Some people with melanoma may be offered a sentinel lymph node biopsy. This procedure checks the first lymph node or nodes most likely to receive drainage from the original tumour. It is not needed for every melanoma, and the decision depends on the individual pathology findings and a discussion of benefits and risks.

If cancer has spread, treatment is planned according to its type, location and extent, as well as the person’s overall health. Options can include surgery, radiotherapy, immunotherapy, targeted therapy and, in some situations, other systemic treatments. Advances in melanoma treatment have improved outcomes for many people with advanced disease, but early detection remains the best protection.

Why early skin checks matter in Australia

Australia has one of the highest rates of skin cancer in the world. High UV levels, outdoor work and recreation, fair skin, a history of sunburn, many moles, immune suppression, and a personal or family history of skin cancer can all increase risk. Skin cancer also occurs in people with darker skin, where it may be detected later because risk is wrongly assumed to be low.

A skin check is not only for people who have noticed an alarming mole. It is a chance to identify lesions in difficult-to-see places such as the scalp, back, behind the ears, soles of the feet and between the toes. Your clinician can advise how often you should be checked based on your personal risk.

Between appointments, get to know your own skin. Ask a partner, friend or family member to help check areas you cannot easily see, or use mirrors and photos to track a mark over time. Do not rely on sunscreen alone: seek shade, wear protective clothing, a broad-brimmed hat and sunglasses, and use broad-spectrum SPF 50+ sunscreen correctly as part of your sun-protection routine.

If you have found a spot that worries you, book a professional skin check now. You do not need to be certain it is cancer before seeking help. The most reassuring outcome is often a benign diagnosis, and the most life-protective outcome is finding a cancer before it has the chance to spread.