skin cancer: should a mole check include my butt?

atypical moles , exposure to sun and ultraviolet radiation have been linked to skin cancer, but other factors , such as living in high altitude areas, having a weakened immune system or being diagnosed with human papilloma virus or hpv may also contribute to skin cancer risk. and just because some areas of the body aren’t exposed to the sun, it doesn’t mean you’re not at risk — skin cancer can also develop under the nails, around the genitals and in the anal area. in fact, according to the canadian cancer society, 20 per cent of melanomas occur in areas that aren’t often exposed to the sun.

“it is unfortunately common enough,” says dr. renée beach , board-certified dermatologist in toronto. “we hypothesize that in these instances, there may be a role of low-grade consistent trauma or genetic predisposition in developing these types of skin cancers.”

while a skin exam should be part of a yearly health checkup, people who have a higher risk of developing skin cancer should be examined more often. some factors that put you at an increased risk include a personal history of skin cancer, light-coloured skin, eyes and hair, many moles or freckles, having had several blistering sunburns as a child, and having had puva therapy for psoriasis

the most common type of skin cancer is basal cell carcinoma — it makes up about 75 per cent of skin cancers and it usually develops on the head, neck and face. it starts in the outer layer of the skin, grows slowly and rarely spreads to other parts of the body.

squamous cell carcinoma makes up 20 per cent of all skin cancers — if found early, it is usually not life-threatening, but if not treated, it can grow into deeper layers of the skin and spread to nearby tissues. some squamous cell carcinoma subtypes tend to have a higher risk of cancer returning after it has been treated.

according to beach, squamous cell cancer on areas like the genitals occurs in both men and women, especially in those with a history of hpv. acral lentiginous melanoma can also form on the palms or soles, neither of which are regularly exposed to the sun.

last year, an estimated 8,000 canadians were diagnosed with melanoma skin cancer, according to the canadian cancer society’s website . melanoma usually starts in an existing mole or new lesion, but unlike basal cell and squamous cell carcinoma, it can quickly spread to other organs if it’s not treated at an early stage. it usually develops on the torso, legs and upper back.

when it comes to skin cancer, telltale signs can include a mole with an irregular size, shape or border, a lesion that is sore, itchy or irritated, raised lumps and rough or scaly patches. early detection is key to improving outcomes, which is why a skin assessment is so critical. according to beach, dermatologists check the whole body during a skin surveillance, from the scalp to the soles of the feet.

researchers have also found that those who consumed omega-3 foods such as salmon, mackerel and trout roughly once a week, developed fewer precancerous skin patches. other antioxidant-rich foods, such as carrots, squash, egg yolks, sweet potato, nuts and berries may also help lower skin cancer risk, while white wine has been linked to certain types of melanomas.