Keep summer sun fun

MUHC doctor offers tips to avoid skin cancer this summer

sun cancerSkin cancer does not occur overnight. It takes years of exposure to the sun or other sources of ultraviolet rays and a little genetic influence. People who burn easily - often those with fair skin - and those genetically predisposed to developing skin cancer or who have a history of family skin cancer are most at risk.

Dr. Beatrice Wang, Acting Director of the Melanoma Clinic at Royal Victoria Hospital site of the McGill University Health Centre (MUHC) and an Assistant Professor of Dermatology at McGill University, can sum up any discussion on skin cancer in one word: prevention.

Lifestyle trends that embrace outdoor activities and social pressures to look tanned play a significant role in our increased exposure to UV rays. According to Wang, the sun's ultraviolet (UV) rays are widely considered to be important in initiating and promoting the disease. It most often appears on the face, trunk or limbs, the areas most often exposed to sunlight, whether through work, play or intentional tanning.

Although skin cancer can appear at any age, it is most common in the over-50 age bracket. However, the worldwide increase in the occurrence of skin cancers has caught the attention of the World Health Organization (WHO), which has recently issued a warning regarding the use of tanning beds. The warning specifically targets teenagers. Wang confirms that there is indeed an increase in the number of reported cases of skin cancer involving persons in their twenties. "External sources of UV exposure should only be provided under medical supervision for specific skin diseases," she says.

Limiting exposure to the sun, whether by staying inside during peak UV periods, or covering exposed skin with clothes or sunscreen are among the best ways to prevent melanoma (see below). But many people are not aware of how to use sunscreen properly, says Wang. "You should use two milligrams of sunscreen for each square centimetre of skin to achieve the stated SPF (sun protection factor)," she says. That's about 30 millilitres, or two tablespoons, per application for an average-sized person.

"That tiny bottle of sunscreen, which normally averages between 120 to 250 millilitres, will not be lasting you the entire summer," she warns. Wang recommends using SPF 30 or greater to get enough protection from UV exposure.

If you notice a new or changing lesion on your skin, the best thing to increase your chances of successful treatment is to observe it carefully (see sidebar) and have it checked by a doctor. "Changing lesions should be examined sooner as opposed to later," she says. "The gold standard of treatment is still surgery. Removing lesions early reduces the risk of metastasis [spread to another region] and may even lead to a cure of the cancer."

Although surgery is the most common way to treat skin cancer, Health Canada recently approved a new drug, imiquimod, commercially available as Aldara, for the treatment of some types of precancerous lesions.

Outside of consultations and treatments, the Melanoma Clinic is also involved in clinical research. The team, which is composed of a dermatologist, a medical oncologist and two surgical oncologists, was recently involved in a clinical trial using a new vaccine to treat the most advanced stage of melanoma (stage 4). As of yet, nothing has replaced prevention or early detection of melanoma for a successful treatment.

 

For more information:

Canadian Dermatology Association: www.dermatology.ca
MUHC Division of Dermatology: www.medicine.mcgill.ca/dermatology
Canadian Cancer Society: www.cancer.ca

Prevent the damaging effects of UV rays

  • use sunscreen with a minimum SPF of 30
  • reapply sunscreen every two hours
  • use a hat, sunglasses and provide ample coverage for torso and limbs as physical blockers from the sun
  • avoid direct sun exposure from 11 a.m. to 3 p.m.
  • avoid sunburns

Know the ABCDEs of melanoma

Asymmetry: moles that are not symmetrical
Border: moles with diffused, unclear edges
Colour: moles that change colour
Diameter: moles that are larger than 6 mm (the size of a pencil eraser)
Evolution: a mole's change in one or all of the above categories