skin cancers

introduction

The epidermis or top layer of skin contains three different types of cells: squamous cells, basal cells and melanocytes. Skin cancer is a disease of the body's skin cells caused mainly by overexposure to ultraviolet (UV) radiation from the sun.

There are three main types of skin cancer named after the type of cells they start from: basal cell carcinoma and squamous cell carcinoma — known as common skin cancers — and melanoma, the most serious type of skin cancer.

Most people living in Australia are at risk of skin cancer, but some people are more at risk. Those at highest risk include: people with fair skin who burn quickly; people exposed to the Australian sun as children; people who suntan deliberately; people with a family history of skin cancer; people who work outdoors for long periods of time; people who use solariums, sunlamps and sunbeds.

Sun Protection

Australia has the highest rate of skin cancer in the world, mostly caused by over exposure to UV radiation (sunlight). Around 380,000 people are treated for skin cancer and 1300 people die from the disease every year.

Mr. Bloom recommends protecting yourself from the sun. This will not only decrease your risk of skin but also avoid many of the aging effects from the sun. Combining the following methods offers the best protection.

SunSmart UV Alert

The SunSmart UV Alert is reported daily in newspaper weather forecasts across Australia. The alert is used to raise public awareness of the risk of exposure to UV radiation and to encourage people to adopt appropriate sun protection measures.

When the UV Index reaches 3 or above, skin damage and particularly sunburn can occur and the risk of skin cancer increases, so sun protection is required.

The alert identifies the times during the day that the UV index will reach 3 or above, so people know when to adopt sun protection measures.

Shade

Shade is one of the most effective ways to protect against the sun's UV rays.

Clothing

Clothing provides a barrier between UV rays and the skin.

Hats

The correct type of hat shades the face, eyes and neck.

Sunglasses

UV rays can also damage eyes. Some styles of sunglasses provide more protection than others. 

Sunscreen

Sunscreen should be the last method of sun protection.

Based on their mechanism of action, topical sunscreens can be broadly classified into two groups, chemical absorbers and physical blockers.

Chemical absorbers work by absorbing ultraviolet (UV) radiation and can be further differentiated by the type of radiation they absorb, UVA or UVB, or both. Physical blockers work by reflecting or scattering the UV radiation.

Physical blockers are effective at protecting against both UVA and UVB radiation. The two most common physical blockers are titanium dioxide and zinc oxide.

SPF stands for Sun Protection Factor and is the system used worldwide to determine how much protection a sunscreen provides, applied to the skin at a thickness of 2 mg/cm2. The test works out how much UV radiation (mostly UVB) it takes to cause a barely detectable sunburn on a given person with and without sunscreen applied. For example, if it takes 10 minutes to burn without a sunscreen and 100 minutes to burn with a sunscreen, then the SPF of that sunscreen is 10 (100/10).

• Apply generously - Most people do not apply enough sunscreen.
• Apply sunscreen 20 minutes before going outdoors to clean, dry skin. This gives it time to bond to the skin.
• Re-apply sunscreen every two hours or more often if you are swimming or sweating a lot.
• Never use sunscreen to extend the time you would normally spend in the sun.

Basal cell carcinoma

Basal cell carcinoma is also known as BCC or rodent ulcer. Basal cell carcinoma is the most common type of skin cancer in humans. Luckily, it is very rarely a threat to life.

BCCs may appear red, pale or pearly in colour. Alternatively they may present as an ulcer or sore that will not heal.

BCC typically affects adults of fair complexion who have had a lot of sun exposure, or repeated episodes of sunburn. Although some hereditary causes of BCCs are described, they are rare and most BCCs are due to sun exposure. BCCs can vary in size from a few millimetres to several centimetres in diameter. They usually grow slowly over months or years.

Squamous cell carcinoma

Squamous cell carcinoma (SCC) is another common type of skin cancer.

The majority of invasive SCCs develop in solar keratoses. Solar or actinic keratoses are common small scaly lesions arising on the face, ears and hands of white skinned people who have spent many years outdoors.

Invasive SCCs vary in size from a few millimetres to several centimetres in diameter. Usually they grow slowly over months or years. Some SCCs appear as sores that fail to heal.

Luckily, SCC is not usually a threat to life as secondary spread (metastasis) is uncommon. SCCs on the lip or ear seem to be the sites most likely to metastasise, so ulcers or lumps in these areas should be taken particularly seriously.

Melanoma

Melanoma is cancer of the skin's melanocytes (pigment cells) and the most dangerous form of skin cancer. If untreated, it can spread to other parts of the body.

A Melanoma may appear as a new spot on normal skin, or develop from an existing mole. If detected early, most melanomas are curable. Later, they become more serious. Melanomas usually begin as a flat spot that changes in size or shape or colour over months. While they are flat they are generally curable.

There are two main types of melanoma.

• Superficial spreading melanoma. It has an uneven, smudgy outline and is an irregular mix of colours.
• Nodular melanoma grows more quickly; it is raised from the start and even in colour. They may be red or pink; some are brown or black.

Melanomas can also arise in areas with minimal sunexposure such as the sole and palms (acral melanomas), under the finger nails (subungal melanomas) and on mucosal surfaces of the body.

Diagnosis of Skin Cancers

Most skin cancers are diagnosed clinically. That is, by taking a history from the patient and examining the lesion.

If Mr. Bloom suspects that you have a skin cancer, to confirm it, he may suggest that you have a biopsy. This is a quick and simple procedure. It is perfromed in the office under local anaesthetic. A small sample of the lesion is removed and sent to a laboratory to be looked at under a microscope.

MoleMap

Another useful adjunct in the diagnosis of skin cancers is photographic mapping of lesions.

MoleMap is a state of the art program involving the digital imaging, archiving and diagnosis of moles and other suspicious lesions.

We are pleased to offer Molemap at our Cato street office.

Treatment of BCCs and SCCs

The treatment of a BCC or SCC depends on its type, size and location, the number to be treated, and the preference of the doctor and patient. Broadly speaking there are two methods of treatment: Non Surgical and Surgical.

Non Surgical methods:

As these lesions only rarely spread it can be possible to treat them with non surgical methods. The advantage of these treatments is that they avoid surgery.

Unfortunately due to the nature of the methods, complete treatment cannot be confirmed and as such the cure rate varies from 60 -90 %. They are not suitable to all forms of BCC or SCC.

It is important to remember that Non surgical does not mean non scarring.

• Shave, curettage, & cautery. Removal of just the top layers of the skin. The wound usually heals within a few weeks without needing stitches. Unfortunately the scarring from this treatment can be worse than with surgery.
• Photodynamic therapy. The tumour is treated with a photosensitising chemical in a cream (e.g. Metvix) or lotion, and exposed to light several hours later. Up to 85% superficial BCCs are cured, with excellent cosmetic results.
• Imiquimod cream. This is applied to superficial BCCs three to five times each week (Monday to Friday) for six to sixteen weeks. The imiquimod results in an inflammatory reaction, maximal at three weeks. Up to 85% of suitable BCCs disappear, with minimal scarring.
• Cryotherapy (freezing). Liquid nitrogen is applied to small superficial lesions. A blister forms, crusts over and heals within several weeks. A permanent white mark usually results from this treatment.
• Radiotherapy (X-ray treatment). This is less commonly used to treat BCCs and SCCs than in the past. It may be a suitable way to eradicate skin cancer on the face in the elderly. The best cosmetic results are achieved by multiple ‘fractions’, e.g. weekly treatments for several weeks.

Surgery

This is the most appropriate treatment for large nodular, infiltrative and BCCs and SCCs.

Depending on the location, size and patient preference, the surgery can be undertaken in the office.
Scars usually heal well and fade over a period of 6-12 months.

Large lesions or lesions where there is a deficiency of skin, may require a flap or graft to repair the defect after excision.

For a graft, a layer of skin is taken from another part of your body and placed over the wound. New blood vessels then grow into the graft. A flap involves moving adjacent skin into the defect from an area of relative excess to close the wound.

Mr Bloom will decide which the most appropriate method of closure is in your particular case.

Cure rates are in the order of 99%. The specimen is routinely sent for histological confirmation of complete excision.

Treatment of melanoma

Melanomas are always removed by surgery. The tumour is cut out, along with an area of normal-looking skin from around the melanoma. The amount of normal skin removed depends on the thickness of the melanoma, and may be from 5mm to 2cm.

In cases where there is limited ‘spare’ skin, skin grafts or skin flaps may be required.

For a graft, a layer of skin is taken from another part of your body and placed over the wound. New blood vessels then grow into the graft. A flap involves moving adjacent skin into the defect from an area of relative excess to close the wound.

Mr Bloom will decide which the most appropriate method of closure is in your particular case.

Regular follow-up, will be arranged following your surgery, as people who have had one melanoma are at increased risk of another melanoma in the future. An important part of your regular follow-up will be the examination of your lymph nodes.

Unfortunately compared with many other forms of cancer there is little in the way of radiotherapy or chemotherapy to additionally treat your melanoma.

Through his association with the Victorian Melanoma Service at the Alfred Hospital, Mr. Bloom is constantly updated on the latest treatment options, including potential trials using vaccines. At present none of these treatments are available outside of a trial setting and are generally reserved only for those with advanced disease.

One area showing some promise in the management of melanoma is sentinel node biopsy. This is a surgical procedure undertaken at the time of your excision, where the first (sentinel) draining lymph node is removed and sent for histological examination. At this time the procedure itself is not thought to be therapeutic but rather only provides additional prognostic information about your melanoma.

The decision whether to undergo such a procedure is a difficult one with many implications. Mr. Bloom will discuss all the pros and cons of having such a procedure. <% End Sub %>