A basic guide to the different types of skin cancer
Up to 90% of non-melanoma skin cancers and 85% of melanoma cases are associated with exposure to ultraviolet radiation (UV) from the sun.
Male skin cancer cases have exploded over the past 20 years and they’re forecast to double over the next 20 years according to the World Health Organisation. In many parts of Europe (including the UK), men are almost twice as likely as women to develop skin cancer.
At LifeJacket, through sharing facts about the dangers of unprotected sun exposure and encouraging people to check their skin for warning signs, we want to improve your skin health. If you think about skin damage on a spectrum, skin cancer is obviously at the extremity. But along that spectrum of damage are more “cosmetic” impacts of redness, pigmentation issues, irritation and wrinkling.
Functions of the skin
In this post we wanted to shine a light on the different types of skin cancer but to achieve that we first need to give a brief overview of the skin’s anatomy.
Broadly speaking skin has seven key biological roles to play;
- Physical barrier function to prevent entry or exit of certain matter.
- Protective function against biological, physical and chemical aggressors.
- Immunological function to prepare a defence against foreign substances.
- Secretory function to regulate sebum, sweat and other lipids.
- Thermoregulatory function to regulate temperature.
- Sensitivity function to communicate information about our immediate environment.
- Absorption function to bring substances into the blood stream when demanded.
To achieve these functions your skin is basically composed of three key layers above the muscle; the epidermis, the dermis, and the hypodermis / subcutaneous layer of fat and connective tissue. A picture paints a thousand words so…
What do the three layers do?
The epidermis is an elastic layer on the outside that is continually being regenerated. It includes;
- Keratinocytes are the main cells of the epidermis and are formed by cell division at its base. These new cells are continually moving outwards to the surface where they are flattened.
- Corneocytes are the flattened dead keratinocytes that make up the very outer layer of the epidermis. This layer is referred to as the stratum corneum or horny layer. It functions as a protective layer that is continually worn away or shed (probably a big component of what you breathe in on the London Underground!).
- Melanocytes are responsible for producing the pigment melanin that protects against UV radiation and gives skin its colour.
The dermis is the inner layer that includes quite a bit of functional anatomy;
- Sweat glands produce sweat that travels to the pores.
- Hair follicles are the pits in which hairs grow which, like sweat, plays a role in temperature regulation.
- Sebaceous glands produce sebum oil to prevent dust and bacteria accumulating on hairs. Sebum and sweat make up the ‘surface film’ of skin which has protective functionality, mainly in regulating moisture loss.
The hypodermis or subcutaneous layer under the dermis is predominately made up of fat and connective tissue to link to the muscle beneath.
The main classifications of skin cancers are melanoma and non-melanoma, the latter of which breaks down into Basal Cell Carcinomas (BCCs), Squamous Cell Carcinomas (SCCs) and Merkel Cell Carcinomas (MCCs).
- Melanoma arises in the pigment cells (the melanocytes).
- Basal Cell Carcinomas (BCCs) begin in the basal cells.
- Squamous Cell Carcinomas (SCCs) are a disease of older cells on the surface skin.
- Merkel Cell Carcinomas (MCCs) are a very rare but aggressive form of skin cancer associated with the Merkel cell polyomavirus virus.
The illustration below shows the main skin cancer types compared to a healthy epidermis;
We are very proud to be an official UK partner of Melanoma UK, a leading skin cancer charity and patient support group. Together, we’re trying to bring much needed attention to the issues about male skin cancer. You can read more about that here and listen to this short video from one of the country’s leading oncologists, Professor James Larkin.
Less common than non-melanoma skin cancers, melanomas are one of the most dangerous forms of skin cancer. Although they can develop from existing moles, about 70% appear as new marks on the skin. They can appear on any part of the skin but in men they are most commonly found on the body and, in women, on the legs.
There are four types of melanoma; Superficial spreading melanoma, Nodular melanoma, Lentigo maligna melanoma and Acral lentigious melanoma.
The ABCD system is universally recognised and helps identify issues. As with anything, if something looks odd or doesn’t feel right always consult a doctor.
Basal cell carcinoma
Basal cell carcinomas (BCCs) are growths that arise from the skin’s basal cells in the outermost layer of skin called the epidermis.
They are the most common form of skin cancer and typically develop following long term exposure to UV in those areas of the body most exposed to the sun such as the face, ears, neck, scalp, shoulders and back.
BCCs can cause quite extensive localised damage and, occasionally, they can metastasise (spread).
Squamous cell carcinoma
Squamous cell carcinomas (SCCs) are the second most common form of skin cancer and are uncontrolled growths of abnormal cells arising from the squamous cells in the epidermis.
Much like BCCs they are most commonly found in those areas most exposed to UV and a good precursor for “at risk” areas are where the skin often reveals cosmetic signs of sun damage such as wrinkles and pigmentation spots.
Sometimes SCCs can grow very rapidly and metastasise if not treated early on. Long-term UV exposure (and in particular sun beds) are the predominant cause of their development.
Merkel cell carcinoma
Merkel cell carcinomas (MCCs) are a very rare but aggressive form of skin cancer associated with the Merkel cell polyomavirus virus.
They’re most prevalent amongst fairer skin types and are often found in those areas most exposed to the sun where they appear as firm, painless lesions or nodules. They carry a very high risk of metastasising which is why early detection is important.
Stay alert for the signs
The different forms of skin cancers tend to appear gradually and can be anywhere on the body, but are commonly found on the areas exposed to the sun (i.e head, neck, lips, ears and the backs of hands).
Generally speaking the cosmetic signs of sun damage such as wrinkles and pigmentation/age spots are strong indications of those riskier areas.
Skin cancers tend not to be particularly painful but sometimes old scars etc that do not heal are also at risk areas. Again, if something looks odd or doesn’t feel right always consult a doctor.
Stay protected. Do it for you.
You wear clothes. You brush your teeth. You wear a helmet when riding a bike. But do you care for your skin? Keep it simple and wear skin protection all year round. Because that’s all the skincare you need. Nothing else is more important for the body’s largest organ.