Skin cancer rates continue to rise dramatically in the United States. Currently, one in six Americans develops skin cancer at some point. Skin cancer accounts for one third of all cancers in the United States. Most of these are non-melanoma cancers such as basal cell carcinoma and squamous cell carcinoma. Mortality associated with these skin cancers is unusual. Melanoma, the eighth most common malignancy in the United States, accounts for 75 percent of all deaths associated with skin cancer.
The rising incidence of skin cancer is thought to be due to increased sun exposure associated with changing lifestyles and the depletion of the protective ozone layer.
Since sun exposure is a major cause of skin cancer, prevention is possible through avoidance. Preventative measures are as follows: sunscreens, clothing and education.
The efficacy of sun protection is measured by its sun protection factor (SPF). The SPF is the ratio of the least amount of UVB radiation required to produce erythema on protected skin compared to the amount of UVB required to produce the same amount of redness on unprotected skin.
Sunscreens function either chemically or physically. Chemical sunscreens absorb UV radiation and therefore reduce skin penetrance by UV radiation. Physical sunscreens reflect UV radiation by providing a physical barrier. Common physical sunscreens are opaque agents such as titanium dioxide, zinc oxide, etc.
Useful sunscreens should have an SPF of at least 15. Sunscreens only provide a mechanism to reduce sun damage – they are not a license to go out under the sun for prolonged periods of time.
Regular clothing provides little protection against the sun. A cotton T-shirt has an SPF of less than 10 – this decreases rapidly when the clothing is wet.
Patients should remember: Sunscreen should be applied 30 minutes before sun exposure and re-applied every 2 hours. Re-apply more frequently after swimming or heavy perspiration.
- Avoid outdoor activity during peak tanning hours.
- Wear additional sun protective clothing.
- DO NOT USE TANNING BEDS.
- Have regular dermatologic evaluations.
The ABCD checklist (A=asymmetry, B=border irregularity, C=color variation, D=diameter > 6mm) has been reported to have a high likelihood of detecting melanoma. The threshold for biopsy may be lowered when a patient is worried that a nevus may be cancerous or reports recent changes in the nevus such as increased size, alteration of shape or color, itching, burning, bleeding or pain.
Clinical studies have shown that even the most experienced physicians can accurately diagnose 71% of malignant lesions and 94% of benign lesions. This strongly suggests that biopsies are indicated since even experienced physicians are unable to predict malignancy.
Benign lesions – the most common pigmented lesions are benign nevi: junctional, compound and intradermal. They can mimic melanoma along with other benign lesions such as seborrheic keratoses and solar lentigines.
|Compound Nevus||Intradermal Nevus|
Pre-cancerous – atypical, dysplastic or Clark’s nevi may all lead to melanoma. Actinic keratosis may transform to either basal or squamous cell cancer. Trichoepithelioma may mimic basal cell cancer. Keratoacanthoma may closely mimic squamous cell cancer.
Malignant lesions – basal cell, squamous cell and malignant melanomas comprise the vast majority of the skin cancers seen in our practice.
|Basal Cell||Squamous Cell||Melanoma|
These lesions can be treated in a variety of ways depending on the discussions between the treating physician and patient. Because these lesions are benign and are very unlikely to become cancerous, watching or observing them over time is a very logical course of action.
Patients who wish to have them removed for cosmetic or other reasons may elect to do so by one of two ways. A dermatologist will often remove these lesions by shaving or scraping them down to the second level of the skin, called the dermis. Plastic surgeons will often remove these lesions by excising, or cutting them out, and carefully repairing the wound with stitches.
The ultimate appearance after one of these procedures varies based on the size and location of the lesion, type of skin, age of the patient and skill of the practitioner. The patient should understand that some type of scar will almost always be present. It is very important for patient and doctor to discuss how conspicuous this scar will likely be in order for the patient to make an appropriate informed decision.
These lesions should usually be biopsied to obtain a tissue diagnosis. Actinic keratoses can be treated topically but atypical, dysplastic, Clark’s nevi, trichepiteliomas, and keratoacanthomas are almost always removed. Dermatologists can remove some of these lesions if they are deemed small enough. Larger lesions are usually referred to a plastic surgeon for excision.
The ultimate appearance after one of these procedures varies based on the size and location of the lesion, type of skin, age of the patient and skill of the practitioner. The patient should understand that some type of scar will almost always be present. It is very important for patient and doctor to discuss how conspicuous this scar will likely be. Because these lesions will often transform into skin cancers, removal is usually recommended, however.
These lesions are always biopsied with a definitive tissue diagnosis prior to removal. This is important because the biopsy will tell not only what type of skin cancer is present, but also its level of aggressiveness. Options for removal are based on the type of cancer, level of aggressiveness, size and location of the lesion, and overall medical health of the patient.
These options include the following. Removal by a dermatologist with cryotherapy or electrodessication and curettage for superficial cancers on the trunk or extremities; more recently topical treatment has been used by some dermatologists for superficial cancers. Surgical removal by a plastic surgeon or specially trained dermatologists, known as a Moh’s surgeon. Finally, radiation therapy may be employed by a radiation oncologist in certain circumstances.