Skin cancers are one of the most commonly diagnosed cancers in Australia. These malignancies of the skin are often forms of carcinomas (cancers arising from tissues that line organs) or melanomas (cancers arising from melanocytes).
The skin is the largest organ in our bodies that protect us from injury, loss of bodily fluids and help regulate body temperature. There are three layers of the skin: epidermis (top layer), dermis (middle layer) and hypodermis (bottom layer). The epidermis is the water-resistant outer layer of the skin that acts as the body’s first line of defence. It contains squamous cellsthe basic structural and functional unit of all living things (upper layer of the epidermis), basal cells (lower layer of epidermis) and melanocytes. The dermis contains the skin’s connective tissues, as well as hair follicles, sweat glands, bloodthe red bodily fluid that transports oxygen and other nutrients around the body vessels, lymph nodessmall bean-shaped structures that filters harmful substances from lymph fluid and nerves. The hypodermis, also known as subcutaneousunder the skin tissuea group of cells that work together to perform a function layer, stores fat (adipose cells), and also contains connective tissue, blood vessels and nerve cells.
Skin cancers are more common in men, and is often diagnosed over the age of 40. However, anyone can develop this disease.
Types of Skin Cancers
There are three primary forms of skin cancers, which are classified by the cells they originate from.
Basal Cell Carcinomas (BCCs)
Basal cell carcinomas (BCCs) are the most common form of skin cancera disease where abnormal cells split without control and spread to other nearby body tissue and/or organs, and develop from the basal cells in the skin. Basal cells are responsible for producing new skin cells as the old ones die. BCCs are often slow growing, are rarely aggressive, and often have a good prognosisto predict how a disease/condition may progress and what the outcome might be.
Squamous Cell Carcinomas (SCCs)
Squamous cell carcinomas (SCCs) are the second most common form of skin cancer, and develop from squamous cells in the skin. Squamous cells are responsible for the filtration and diffusion of substances to pass through the skin. SCCs can be aggressive, and can have a good prognosis when caught early.
Melanoma
Melanomaa type of cancer that develops from melanocytes, which are the cells that produce pigment generally in the skin (but can develop in other areas of the body) is a rare form of skin cancer that develops from melanocytes, which are the cells that produce pigment in the skin. While melanomas are most commonly in the skin (cutaneous melanoma), they can also develop in the eye (ocular melanoma), nails (nail unit melanoma), or in mucosal surfaces (mucosal melanoma).
Rare forms of Skin Cancer
These types of skin cancers are very rare:
- Atypical Fibroxanthoma.
- Dermatofibrosarcoma Protuberans (DFSP)
- Extramammary Paget disease.
- Merkel Cell Carcinoma.
- Sebaceous Carcinoma.
Treatment
If skin cancer is detected, it will be staged and graded based on size, metastasiswhen the cancer has spread to other parts of the body, also known as mets, and how the cancer cells look under the microscope. Stagingthe process of determining how big the cancer is, where it started and if it has spread to other areas and grading helps your doctors determine the best treatment for you.
In most cases, BCCs and SCCs rarely need staging and grading as they are often slow-growing or don’t have other high-risk features. If your skin cancer does require staging, it will be staged using the TNM staging system:
- T (tumoura tissue mass that forms from groups of unhealthy cells) indicates the size and depth of the tumour.
- N (nodea small lump or mass of tissue in your body) indicates whether the cancer has spread to nearby lymph nodes.
- M (metastasis) indicates whether the cancer has spread to other parts of the body.
This system can also be used in combination with a numerical value, from stage 0-IV:
- Stage 0: this stage describes cancer cells in the place of origin (or ‘in situ’) that have not spread to nearby tissue.
- Stage I: cancer cells have begun to spread to nearby tissue. It is not deeply embedded into nearby tissue and had not spread to lymph nodes. This stage is also known as early-stage cancer.
- Stage II: cancer cells have grown deeper into nearby tissue. Lymph nodes may or may not be affected. This is also known as localisedaffecting only one area of body cancer.
- Stage III: the cancer has become larger and has grown deeper into nearby tissue. Lymph nodes are generally affected at this stage. This is also known as localised cancer.
- Stage IV: the cancer has spread to other tissues and organs in the body. This is also known as advancedat a late stage, far along or metastatic cancer.
Cancers can also be graded based on the rate of growth and how likely they are to spread:
- Gradea description of how abnormal cancer cells and tissue look under a microscope when compared to healthy cells I: cancer cells present as slightly abnormal and are usually slow growing. This is also known as a low-grade tumour.
- Grade II: cancer cells present as abnormal and grow faster than grade-I tumours. This is also known as an intermediate-grade tumour.
- Grade III: cancer cells present as very abnormal and grow quickly. This is also known as a high-grade tumour.
Once your tumour has been staged and graded, your doctor may recommend genetic testinga procedure that analyses DNA to identify changes in genes, chromosomes and proteins, which can be used to analyse tumour DNA to help determine which treatment has the greatest chance of success, which analyses your tumour DNA and can help determine which treatment has the greatest chance of success. They will then discuss the most appropriate treatment option for you.
Treatment is dependent on several factors, including location, stage of disease and overall health.
Treatment options for skin cancer may include:
- Surgerytreatment involving removal of cancerous tissue and/or tumours and a margin of healthy tissue around it to reduce recurrence, potentially including:
- Surgical excisionto surgically remove/cut out of cancerous tissue.
- Mohs micrographic surgeryspecialised surgery that removes thin layers of cancer in stages until completely removed.
- Reconstructive surgerysurgery to restore appearance and/or function to an area of the body – such as a skin flap or skin graft (suitable for patients who have had a large skin cancer removed).
- Curettagea procedure where the cancer is scraped out with a small, sharp instrument (curette) and electrodessication.
- Cryotherapythe process of freezing off cancerous tumours and/or lesions using liquid nitrogen.
- Photodynamic therapya procedure that involves inserting a light-sensitive drug (photosensitiser) to shrink and damage cancer cells when exposed to a light source.
- Radiation therapya treatment that uses controlled doses of radiation to damage or kill cancer cells.
- Immunotherapya treatment that uses a person's immune system to fight cancer.
- Clinical trialsresearch studies performed to test new treatments, tests or procedures and evaluate their effectiveness on various diseases.
- Palliative carea variety of practices and exercises used to provide pain relief and improve quality of life without curing the disease.
Risk factors
Riskthe possibility that something bad will happen factors that may increase the likelihood of developing skin cancers include:
- Having pale or freckled skin (especially if it burns easily and doesn’t tan).
- Having red or blond hair.
- Having light-coloured eyes, such as blue or green.
- Prior exposure to ultra-violet (UV) radiation.
- Tanning/solarium usage.
- Exposure to arsenic.
- Having a weakened immune system.
- Having lots of moles, especially those that are irregularly shaped and/or uneven in colour.
- Having a family history of skin cancer.
- Having a personal history of skin cancer.
- Having certain skin conditions, such as:
- Sunspots.
- Dysplastic naevus.
- Age spots (also known as seborrheic keratoses).
Not everyone with these risk factors will develop the disease, and some people who have the disease may have none of these risk factors. See your general practitioner (GP) if you are concerned.
Symptoms
Symptoms of skin cancers often vary by subtype.
Symptoms of Basal Cell Carcinomas
Symptoms of BCCs may include:
- Lumps on areas exposed to skin, including the head, face, neck, shoulders, lower arms and legs.
- Pearl-coloured lump.
- A pale or bright pink scaly area around the lump.
- Skin ulceration.
- Bleeding.
- Inflammation.
Symptoms of Squamous Cell Carcinomas
Symptoms of SCCs may include:
- Lumps on areas exposed to skin, including the head, face, neck, shoulders, lower arms and legs.
- Rapidly growing lump.
- Thickened, red, scaly or crusted spot.
- Bleeding.
- Inflammation.
- Tender to touch.
Symptoms of Melanoma
Cutaneous melanomas often appear as unusual moles, freckles, or spots. However, their appearances can vary greatly depending on cancer type, age of the patient and other individual factors. Generally, most types of cutaneous melanomas have characteristics that can be described by the Glasglow 7-point checklist and/or the ABCDEFG of melanoma.
For more symptoms on the symptoms of melanoma, please refer to the Rare Cancers Australia Melanoma (Cutaneous) page.
Not everyone with the symptoms above will have cancer, but see your GP if you are concerned.
Diagnosis
If your doctor suspects you have skin cancer, they may order the following tests to confirm the diagnosisthe process of identifying a disease based on signs and symptoms, patient history and medical test results and refer you to a specialist for treatment:
- Physical examinationan examination of your current symptoms, affected area(s) and overall medical history.
- Biopsyremoval of a section of tissue to analyse for cancer cells.
