Skin cancer: Early identification is of critical importance

Although it is the most common cancer in Canada, skin cancer is largely preventable, detectable and curable. You can protect your health by taking steps to prevent skin cancer, learning what skin cancer looks like and taking action if you find something unusual.

By Dr. Richard Langley

It is estimated that one in five North Americans will develop a skin cancer over the course of their lifetime. The incidence of melanoma, the most dangerous of the skin cancers, has increased almost threefold over the past three decades.

Despite these staggering statistics, if detected early, skin cancer can be successfully treated. Melanoma, if caught in its early stages, is curable, or, when minimally invasive, highly curable; whereas people with melanoma that has metastasized to the brain have an average survival rate of only four months. This underscores the critical importance of early diagnosis and prompt excision of malignant skin cancer.

The most common form of skin cancer, basal cell cancer, rarely metastasizes. Still, even for this form of cancer, it is important to diagnose it early as it can be locally invasive and cause significant morbidity in patients.

Why is prevention important?

Skin cancer is largely preventable. The most important risk factors for melanoma include light skin colour, red or blond hair, a history of sunburns (particularly blistering sunburns), a family history of melanoma in at least two first-degree relatives and a prior history of melanoma. Some of these risk factors, such as sun exposure, can be minimized, particularly sunburns and blistering sunburns.

We also know that for the most common skin cancer, basal cell carcinoma, the most significant risk factor is chronic sun exposure. Over 80 per cent of all basal cell skin cancers occur on the head and neck, occurring in areas of maximum sun exposure.

Solar radiation has been identified as a carcinogen by the World Health Organization, and its clear link in epidemiological studies of skin cancer underscores the importance of prevention. In general, we recommend that patients avoid the midday sun (from 11 a.m. to 3 p.m.), wear a sunscreen with an SPF of at least 30, wear sun-protective clothing and avoid artificial forms of radiation. These precautions have been shown to reduce the formation of skin cancers and are an important step that we can all take to prevent skin cancer.

Self-detection works: over 50 per cent of all melanomas were self-detected by patients.

What are the signs of skin cancer, and what do I do if I find something?

Look for new or changing skin lesions, monitor them and get them assessed if you are concerned. Sustained change over the course of weeks or months is a significant risk factor for skin cancer.

For melanoma, a helpful mnemonic is the ABCDEs:

A: Asymmetry in the shape or colour of a pigmented lesion
B: Irregular or jagged border
C: Variegation in colours, such as shades of brown, black, red or white
D: A diameter greater than 6 mm
E: Evolution or change in a lesion as noted above

Self-detection works: over 50 per cent of all melanomas were self-detected by patients. If you identify a suspicious lesion, it is best to bring it to the attention of your family physician. If he or she is concerned, they may do a biopsy (remove the lesion) or refer you to a dermatologist for examination.

What happens if I am diagnosed with skin cancer?

Remember that most skin cancers are curable or highly curable. Your treatment options depend on the type of skin cancer you have been diagnosed with.

If you have a basal cell skin cancer or squamous cell skin cancer, these can typically be cured by surgical removal of the tissue along with a minimal amount of surrounding normal skin. Certain types of basal cell skin cancers (basal cell cancers around the eyes, certain locations on the nose or a specific type of basal cell cancer called morpheaform) may require specialized surgery known as Mohs surgery. This type of surgery will remove the cancer in several stages to ensure that all of the cancer cells have been removed.

For melanoma, the stage of the cancer will determine your best treatment option. Most melanomas are either in the outer layer of the skin (epidermis) or have just penetrated into the skin. In this case, the thickness of the tumour (how far it penetrates into the skin) will determine how wide a margin of normal skin you need to have removed. Patients who have thicker tumours may also require a specialized biopsy of a node called a sentinel lymph node biopsy.

Although skin cancer is the most common cancer, the prognosis is excellent if the cancer is diagnosed early and treated appropriately. Keep in mind that many skin cancers can be prevented by minimizing exposure to the harmful rays of the sun.

As we all enjoy the warmth of summer, it is important to remember that we need to enjoy the sun in a safe and responsible way.

Dr. Richard Langley is a professor and Director of Research in the Division of Dermatology, Department of Medicine, Dalhousie University, and President-elect of the Canadian Dermatology Association. He has received numerous awards for teaching, research, clinical practice and volunteer activities.