Joseph F. Coffey, BSc, MD, Currently PGY4 Dermatology, University of Alberta, Edmonton, AB.
Gordon E. Searles, OD, MD, MSc, FRCPC, Assistant Clinical Professor; Program Director, University of Alberta, Edmonton, AB.

Accumulation of sun exposure is an important factor resulting in aging of the skin and development of cutaneous malignancy. Unfortunately, most people think of suntanning as a healthy, natural process, and damaging effects of the sun are not experienced until 15-20 years after the initial damage has been done. By the time we see patients in our clinic, the majority of our older clientele has extensive, irreversible photo damage and precursors of skin cancer. It is difficult to treat many of these patients as multiple lesions are frequently present, and patients are sometimes unwilling to initiate sun-protective measures, are not ideal surgical candidates, and may not comply with treatments suggested by the dermatologist due to financial burden. We emphasize the critical role of sun exposure as a cause of skin aging, benign stigmata of aging, and development of skin cancers. Treatment options including topical therapies, oral medications, surgery, and new-age technologies are discussed.
Key words: photo-aging, therapy, skin cancer, dermatoheliosis, melanoma.

John E. Adam MD, FRCPC, Professor of Medicine (Dermatology), University of Ottawa, Ottawa, ON.

The annual number of new cases of skin cancers reported in Canada is estimated to be about 40,000. With the aging of the baby boomer generation, this figure is anticipated to increase because of the ease of travel to the south in winter and increased exposure to the sun during outdoor activities. Dermatoheliosis or photodamage is most prevalent in people over 40 years of age who have had excessive sun exposure over their lifetime (Table 1). Epidemiological studies have identified sunlight exposure as the major risk factor for skin cancer.

There are three major types of skin cancer. The most common non-melanocytic skin cancers are Basal Cell Carcinoma and Squamous Cell Carcinoma. The less frequently occurring melanocytic skin cancer is Malignant Melanoma.

Basal cell carcinoma
Basal Cell Carcinoma (BCC) is the most common form of skin cancer but also the least likely to metastasize. It can be very destructive locally if not diagnosed and treated early.

Clinically it presents in several forms on sun-exposed areas (Table 2). The classic and most common presentation is the nodulo-cystic variety--a shiny elevated dome shaped nodule with a raised border often with telangiectatic blood vessels on the surface. The tumour is described as shiny or of a "mother-of-pearl colour.

Michelle Durkin, BSc

The most common form of cancer today is skin cancer. Approximately half of all new cancers diagnosed are one of three defined types: basal cell carcinoma (BCC) , squamous cell carcinoma (SCC), or malignant melanoma (MM). Although the age of diagnosis is decreasing, most skin cancers do not appear until after the age of fifty, making this disease a serious threat to the elderly population. Fortunately it is also a disease which is successfully treated if detected early.

Epidemiology
The incidence of nonmelanoma (BCC and SCC) and MM skin cancers has increased so significantly over the past few decades it may have reached epidemic proportions, particularly in the United States and Canada. It has been projected by the National Cancer Institute along with the Center for Disease Control that in 1999 alone, skin cancer (all types combined) will claim the lives of nearly 9,200 people in the United States. Besides increasing annual incidence, more women are getting skin cancer and people are getting skin cancer at younger ages.

Individual types of skin cancer follow different morbidity and mortality distributions. About 80% of skin cancers are BCC, 16% SCC, and 4% MM. The mortality rate for nonmelanoma skin cancer is decreasing and that of melanoma is increasing.