Skin Cancer and Melanoma
Over 3.5 million new cases of skin cancer are diagnosed yearly. Most cases are preventable and for those that do occur, many are treatable. One type of skin cancer, malignant melanoma, is often lethal. Reducing exposure to the sun and ultraviolet radiation is the cornerstone of prevention. Regular skin examination is the key to early detection and cure. FAA policy on medical certification of pilots with skin cancer depends on the type of cancer and extent of disease.
Types of Skin Cancer
Skin cancer is generally divided into two major categories: melanoma and non-melanoma skin cancers. There are several sub-groups of malignant melanoma, and two major types of non-melanoma skin cancers: basal cell carcinoma and squamous cell carcinoma. Bowen’s Disease is considered an early form of squamous cell carcinoma. Other non-melanoma skin cancers make up less than 1% of all skin cancers.
One in five Americans will have some form of skin cancer in their lifetime. Basal cell carcinoma is the most common with an estimated 2.8 million cases diagnosed annually. Luckily this remains rarely fatal.
Nearly 700,000 cases of squamous cell carcinoma occur annually with a steady increase in the last few decades. About 2 percent of squamous cell carcinoma patients died from the disease in the US in 2012 (note these are not typically superficial skin lesions). Approximately 90% of nonmelanoma skin cancers are associated to ultraviolet radiation by sun exposure.
Melanomas, though relatively small in number, are the most serious type of skin cancers. One person dies of melanoma every hour with an estimated 77,000 new cases diagnosed in the US annually. Melanoma accounts for less than 5% of skin cancer, but also for the overwhelming majority of skin cancer deaths. From 1970 to 2009 the incidence of melanoma increased by 800 percent in young women and 400 percent among young men.
Numerous risk factors exist for all types of skin cancer. Some factors are controllable, while others are not. Those not modifiable are gender, natural skin pigmentation, age and immune system status. Over half of all skin cancers occur in people over age 50. Persons with fair skin have significantly higher risk than those with dark skin. Fair skinned white individuals have four times the risk as olive skinned Caucasians and twenty times the risk of African Americans.
Modifiable risk factors include sun exposure and UV radiation doses, cigarette smoking, sexual contact with human papillomavirus, chemical exposures and certain medications. The easiest to control is sun exposure and UV radiation.
Non-melanoma skin cancers (basal cell and squamous cell carcinoma) are related to cumulative sun exposure over a lifetime. Therefore, incidence increases with age. Fair skinned people living near the equator are at highest risk. Recently, individuals of higher income and more leisure time have documented increased risks for these cancers, presumably due to increase time exposed to the sun. Many of these individuals will have pre-cancerous changes in their skin.
Melanomas are not directly related to chronic sun exposure, but rather to a history of brief, intense, blistering sun exposure, particularly as a child or adolescent. Over 80% of most individuals’ total body exposure to sun occurs by age 18 years.
Location and Spread (Metastasis)
The non-melanoma skin cancers are most commonly found on the face, ears and neck. The backs of the hands are another common location. These areas are most often sun exposed on a chronic basis, particularly in men. People exposed to human papillomavirus may get cancers of the genital and anal skin.
With respect to the skin, basal cell carcinomas arise from the bottom layer of the epidermis, the basal cell layer. Growth of basal cell carcinomas is primarily confined to the local skin area. They rarely spread to other areas of the body (metastasize), but if left untreated, can cause damage to local structures. Invasion of adjacent bone is possible in untreated basal cell carcinomas. If resected, these cancers tend to recur in the same location as the original cancer, though new basal cells can occur in other locations of the body.
Squamous cell carcinomas also tend to invade local areas and can recur in the same location as an original lesion. They are more likely to spread to other areas of the skin, but tend not to spread through the lymph nodes. Squamous cell carcinomas arise from the more superficial layers of the skin.
Melanomas are found anywhere on the body, but most commonly on the upper back of men and women and the backs of legs of women. Unusual locations for melanomas include under the fingernail bed and in the retina of the eye. These cancers originate in the pigmented cells of the skin, called the melanocytes. Because of their cells of origin, melanomas are nearly always pigmented with a brown, black or bluish color.
Unlike non-melanotic skin cancers, melanoma is much more likely to spread to distant areas of the body. The cancer may extend to deeper layers of tissue like the other skin cancers. However, non-contiguous spread to other areas of the skin, termed “satellite lesions”, is common. Melanomas may also spread through the lymph nodes to distant parts of the body. Finally, metastases to the brain and distant organs is common in more advanced melanomas
Appearance and Characteristics
Basal cell carcinomas have a similar appearance to pale moles or are described as smooth, usually symmetric, wart-like bumps. They may be flesh colored, pale or reddish, often with fine blood vessels visible. Occasionally, there may be ulceration of the basal cell carcinoma. A definite edge to the carcinoma is usually visible with stretching of the lesion.
Squamous cell carcinomas generally begin as flat areas of scaling and redness of the skin. Pre-cancerous lesions, called actinic keratoses, will have a hard white scale over a red base. The scale may be scratched off, but tends to recur in the same location. As squamous cell carcinomas grow, they tend to become a deeper red color, increase in diameter and may develop central ulceration. The edge is less distinct than that of basal cell carcinomas. Squamous cell carcinomas may also develop a nodular appearance.
Melanomas are much more variable in appearance. The commonly used mnemonic for remembering melanoma appearance is “ABCDE”. “A” stands for “Asymmetry” represented by one side of the lesion not matching the other side. “B” represents “Borders” which are irregular and notched. “C” indicates that the “Color” is variable, often with multiple shades in the pigmented lesion. “C” may also stand for changing appearance or size. “D” represents “Diameter” of greater than 6 mm, or ¼ inch. “E” represents “Elevation” as most benign moles tend to be flat, melanomas will develop a raised surface.
The above distinguishing features are general guidelines only–of course, any suspicious skin lesion should be checked by your physician. Persons with large numbers of moles are at greater risk for melanoma and careful personal and professional examinations are important for early detection.
Skin cancers may be treated in several ways. The optimum treatment depends on the type of cancer, its depth and its circumference. Location of the cancer, particularly if on the face, and patient preference also are determining factors.
Basal cell carcinomas may be treated with cryotherapy (freezing), excisional biopsy (surgically removing the tumor) or by curettage (scooping out the cancer) with electrodessication (cauterization). Mohs micrographic surgery involves progressively shaving off layers of the tumor until microscopic analysis indicates that the deepest layers are tumor free. Other less common treatments involve oral medications, radiation therapy and lasers.
Squamous cell carcinomas are often preceded by pre-cancerous actinic keratoses (AKs) described above. AKs are usually frozen off with liquid nitrogen applied weekly for several weeks. A medication applied to the skin, called 5-FU, is often used on the face. Surgical excision is usually not necessary in early squamous cell carcinomas. When necessary, Mohs micrographic surgery is usually appropriate. More advanced lesions or those that have metastasized may require extensive surgery or chemotherapy. Metastatic squamous cell carcinomas only have a 34% 5-year survival rate.
Malignant melanomas are much more aggressive tumors that demand a wider range of treatments depending on the circumstances. The simplest treatment is excision, or surgical removal of the cancer. Generally, a wide margin of surrounding normal tissue is also removed to decrease the chances of leaving any microscopic melanoma cells.
In melanomas found on the fingers and toes, particularly those of deeper penetration, amputation of the finger or toe may give the patient the best chance of survival. Deeper lesions found anywhere on the body may dictate an extensive regional lymph node removal to determine the extent of spread and to decrease the risk of missing a metastatic ‘seed ‘ in the lymph nodes.
If the melanoma has spread to a distant organ, usually the liver, lung or brain, the 5-year survival drops to 5%. Although surgical removal of the metastasis will not result in a cure, it may improve patient comfort and quality of life. Metastatic melanoma also can be treated with chemotherapy and radiation therapy, but survival is not significantly extended.
Immunotherapy is the newest form of routinely practiced treatment for advanced melanoma. Two types of immunotherapy include cytokine and vaccine therapy. Both of these treatments are designed to boost the individual’s immune system in an attempt to kill quickly growing melanoma cells. Cytokine therapy uses compounds called interferon-alpha and interleukin-2. A variety of antiviral vaccines may be used to stimulate the body’s immune system.
Clinical trials are being conducted at many research institutes to investigate experimental forms of therapy.
The key to prevention is avoidance or protection from sun exposure and ultraviolet radiation. The most intense sun is found from 10 AM until 4 PM. Outdoor activities during these times should be minimized. People participating in outdoor activities during these times should consider wearing long sleeves and pants with sun glasses and a broad brimmed hat that shades not only the face, but also the ears and neck. This is especially true for sun exposures in lower latitudes and higher altitudes.
Ultraviolet Radiation and Skin Damage
When complete protection from the sun in the form of clothing or shade is not possible, sunscreen use provides the best protection from the damaging radiation from the sun that can cause skin cancers and premature aging. To be able to determine which sunscreen product is most appropriate, an understanding of the sun’s skin-damaging electromagnetic radiation spectrum is in order.
The ultraviolet (UV) portion of the sun’s electromagnetic spectrum causes damage to the skin. The UV portion is divided into the UVA and UVB, with the UVA being further divided into UVA I and the UVA II. The most damaging portion is the UVB, followed by UVA II and least damaging is UVA I. Skin damage and cancer is caused by damage to the DNA in skin cells. Changes in DNA are cumulative. DNA damage can lead to abnormal growth of cells which, over time, may cause cancer. This damage may also cause premature wrinkling and aging of the skin. The UV spectrum also stimulates the skin to produce more melanin from melanocytes. This dark colored melanin is responsible for a tan. Tanning booth lamps give off large amounts of UVB radiation to give a quick tan.
Individual sensitivities to sun exposure varies, primarily with natural skin pigmentation. Medications and some medical conditions may temporarily increase an individual’s sensitivity. Sensitivity is quantified by noting the amount of redness, known as “erythema”, of the skin following an exposure to UV radiation. Sunburns are erythema of the more superficial skin cells, primarily caused by UVB radiation. The infrared (IR) spectrum gives the sensation of heat. Therefore, the perceived outside temperature plays no role in sunburn or tan, as evidenced by skiers getting severe face burns on very cold days.
Sunscreens are designed to block the damaging UV radiation. The degree of protection is measured in units of SPF, or Sun Protection Factor. The SPF is measured by determining the multiple of time exposed to the skin to produce the same amount of erythema in unprotected skin. For example, if an individual gets a certain amount of erythema within 24 hours after 10 minutes of exposure to the sun, the same individual using an SPF 15 product could remain in the sun 150 minutes, or 2 hours and 30 minutes (15 times 10 minutes) to get the same amount of erythema.
SPF is only quantified for UVB radiation protection. UVA protection is difficult to measure because the UVA spectrum does not significantly contribute to erythema. The FDA will allow manufacturers to claim UVA protection if the product blocks any of the UVA II spectrum. Factors such as wind, water, perspiration and others may reduce the effective SPF. Insect repellents with DEET may reduce the effective SPF.
Sunscreens claim a broad range of SPFs, from 2 to 65. SPFs of higher than 30 have essentially no additional protective effect than an SPF of 30 does. An SPF of 15 only allows 6.4% of UVB to reach the skin, while an SPF of 30 allows 3.3% of UVB to penetrate. An SPF of 60 would only block another 1.7% of the UVB radiation.
Sunscreen should be applied at least 20 minutes prior to sun exposure for maximal effectiveness. People tend not to apply sunscreen evenly to all areas of the skin. Therefore frequent applications provide more uniform protection. Exposure to water and toweling off reduces sunscreen protection. Reflective surfaces such as water, sand, snow and concrete will increase intensity of UV radiation. Clouds shield IR radiation and lower temperatures, but allow significant UV penetration. As a general rule, if a shadow is visible, UV radiation is reaching exposed skin.
Aircraft windscreens and canopies generally do not allow UV radiation to penetrate. Therefore pilots are not at risk for increased exposure to UV radiation when piloting an aircraft, although time spent on the tarmac certainly can be associated with exposure to harmful UVB radiation.
Tips for Reducing Risk from UVB
- These tips are collected from a variety of sources noted in the references below.
- Stay out of the sun between 10 AM and 4 PM
- Use covering clothing, hats and sunglasses when outdoors
- Use sunscreen of SPF 15 – 30 that is water resistant
- Be aware of reflected sunlight off water, sand, concrete and snow
- Apply sunscreen at least 20 minutes before sun exposure
- Reapply sunscreen often, particularly when exposed to water or perspiration
- Avoid sun lamps and tanning booths
- Read medication labels for possible skin sensitizing side effects
- Don’t smoke
- Protect yourself every time you are out in the sun
- Protect children from intense sun exposure as they are at highest risk
FAA Policy on Melanoma and Skin Cancer
Pilots and controllers with a diagnosis of skin cancer may not fly or control until the cancer is removed. Note that for superficial, non-melanoma, skin cancers that would not interfere with safe performance of aviation duties, the Regional Flight Surgeon or Aviation Medical Examiner is likely to allow routine aviation duty until removal is scheduled. Those with basal cell carcinomas and squamous cell carcinomas may return to aviation duties after surgery which completely removes the cancer and treatment is complete. Controllers will need to obtain specific Regional Flight Surgeon clearance before returning to controlling. For pilots, reporting to the FAA may be accomplished at the time of the next medical application on FAA Form 8500-8. Pilots are advised to bring documentation from their treating physician regarding the cancer to their AME. Those rare basal cell and squamous cell carcinomas that cannot be completely resected, require ongoing therapy or that have metastasized are disqualifying for flight duties until the medical documentation has been reviewed and cleared by the FAA.
Melanomas are disqualifying for aviation duties. The length of disqualification depends on the depth and stage of the melanoma. Pilots/controllers with melanomas may have their cases reviewed by the FAA for return to flying/controlling as soon as treatment is complete, if there is no evidence of metastasis or if metastases are confined to regional lymph nodes until treatment is complete. Metastases to distant organs (besides the brain) are disqualifying for a minimum of three years following completion of treatment. Brain metastases disqualify an individual for at least five years following completion of treatment. Each of these cases requires reporting and clearance by the FAA before returning to flying or controlling. A Special Issuance Authorization will be issued to pilots cleared to fly after more extensive melanomas are diagnosed and successfully treated. Controllers would receive a Special Consideration to return to safety sensitive duty.
For superficial melanomas that measure less than 0.75mm in depth, the airman can return to flying after recovery from complete excision, but are expected to report the issue to the FAA at that time. AMAS physicians can assist airmen in determining if they meet these criteria.
AMAS Aeromedical Assistance
The AMAS physicians have assisted numerous professional pilots, recreational pilots, and controllers to return to aviation duties following a diagnosis of skin cancer. If you would like specific answers to your situation or assistance in reporting your condition to the FAA, please use the AMAS Confidential Questionnaire. For Corporate clients, these services are provided at no charge to you.