Skin cancer is the most common cancer in the world. In fact, more people are diagnosed with skin cancer each year than all other cancers combined. The good news? Around 90% of cases are preventable.
Obviously, skin cancer is at the extremity when it comes to skin damage. At the other end of the scale, you have redness, soreness, dryness, itchiness, pigmentation, premature ageing and hundreds of things in between. Investing in everyday skin protection can go a long way to keeping your skin health in check, for as long as possible.
So, if you spend time outdoors — whether it’s running, cycling, hiking, swimming, skiing or anything in between — it’s important to know a few things. Because there’s a right way to protect your skin, and there’s a wrong way.
Here’s what you need to know starting with a little bit of biology!
Functions of the skin
Broadly speaking skin has seven key 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 here you go...
What do the three layers do?
The epidermis is an elastic layer on the outside that's continually being regenerated. It includes:
-
Keratinocytes which 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're flattened.
-
Corneocytes which 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's continually worn away or shed (probably a big component of what you breathe in on the London Underground!).
-
Melanocytes which 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.
What is skin cancer?
Skin cancer is the uncontrolled growth of abnormal skin cells. It happens when the skin has been damaged, often by ultraviolet (UV) radiation from the sun or tanning beds. Over time, this damage can cause mutations in the DNA of skin cells, which may lead to cancer.
The main classifications of skin cancers are melanoma and non-melanoma.
-
Melanoma arises in the pigment cells (the melanocytes). The most dangerous form. It can spread quickly to other parts of the body. Early detection is critical.
-
Basal Cell Carcinomas (BCCs) begin in the basal cells. The most common form. It grows slowly and rarely spreads but can cause significant damage if untreated.
-
Squamous Cell Carcinomas (SCCs) are a disease of older cells on the surface skin. The second most common. It’s more likely than BCC to spread if not caught early.
-
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.
Melanoma
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.
We're 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 skin cancer. You can read more about that here.
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're the most common form of skin cancer and typically develop following long term exposure to UV in 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're most commonly found in 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.
Check your skin regularly
In broad brush strokes, two-thirds of men's skin cancer cases are above the waste whereas, for women, two-thirds are from the waist down.
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 riskier areas so keep an eye on the entire body by carrying out a skin check every 2-3 months.
Skin cancers tend not to be particularly painful but sometimes old scars that don't heal are also at-risk areas. If something looks odd, is changing or doesn't feel right, consult a doctor. They won't think you're wasting their time and would rather see you early than not at all.
What causes skin cancer?
The number one cause is exposure to UV radiation from the sun or artificial sources like tanning beds. But not all UV exposure is equal. Intense, intermittent sun exposure — like getting sunburned on holiday — is particularly risky.
Other risk factors include:
- Fair skin or light-coloured eyes
- A history of sunburn
- Lots of moles or freckles
- A family history of skin cancer
- A weakened immune system
- Exposure to certain chemicals
How can you reduce your risk?
Skin cancer is largely preventable with a few simple habits:
-
Wear sunscreen daily. Use a broad-spectrum SPF 30 or higher, even when it’s cloudy. Reapply every two hours when outside.
-
Cover up. Wear UPF-rated clothing, a wide-brimmed hat and sunglasses.
-
Avoid peak sun hours. UV rays are strongest between 11am and 3pm.
-
Skip the tanning beds. Just don’t.
-
Check your skin regularly. Look for new or changing moles or spots. If in doubt, get it checked by a professional.
Why it matters
Rates of skin cancer have doubled in the UK since the 1990s and are expected to double again over the next 20 years. But it doesn’t need to be this way.
No one should have to stop doing what they love outside. And no one should face something so serious when it’s so easy to avoid.
Protecting your skin isn’t about vanity. It’s about health. Long-term health.
So whatever you’re doing today — heading out for a ride, a run, a hike or just walking the dog — take 30 seconds to think about your skin.
We’ve got your back.
