Episode 14, Skin Cancer
One in six Americans develop skin cancer at some point in their life, and skin cancers account for one-third of all cancers in the country. On this edition of “To Your Health With Dr. Jim Morrow,” Dr. Jim Morrow addresses the prevention of and screening for skin cancer, as well as specific skin cancers to be aware of. “To Your Health” is brought to you by Morrow Family Medicine, which brings the CARE back to healthcare.
About Morrow Family Medicine and Dr. Jim Morrow
Morrow Family Medicine is an award-winning, state-of-the-art family practice with offices in Cumming and Milton, Georgia. The practice combines healthcare information technology with old-fashioned care to provide the type of care that many are in search of today. Two physicians, three physician assistants and two nurse practitioners are supported by a knowledgeable and friendly staff to make your visit to Morrow Family Medicine one that will remind you of the way healthcare should be. At Morrow Family Medicine, we like to say we are “bringing the care back to healthcare!” Morrow Family Medicine has been named the “Best of Forsyth” in Family Medicine in all five years of the award, is a three-time consecutive winner of the “Best of North Atlanta” by readers of Appen Media, and the 2019 winner of “Best of Life” in North Fulton County.
Dr. Jim Morrow, Morrow Family Medicine, and Host of “To Your Health With Dr. Jim Morrow”
Dr. Jim Morrow is the founder and CEO of Morrow Family Medicine. He has been a trailblazer and evangelist in the area of healthcare information technology, was named Physician IT Leader of the Year by HIMSS, a HIMSS Davies Award Winner, the Cumming-Forsyth Chamber of Commerce Steve Bloom Award Winner as Entrepreneur of the Year and he received a Phoenix Award as Community Leader of the Year from the Metro Atlanta Chamber of Commerce. He is married to Peggie Morrow and together they founded the Forsyth BYOT Benefit, a charity in Forsyth County to support students in need of technology and devices. They have two Goldendoodles, a gaggle of grandchildren and enjoy life on and around Lake Lanier.
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Dr. Morrow’s Show Notes on Skin Cancer
- One in six Americans develops skin cancer at some point.
- Skin cancer accounts for one third of all cancers in the United States.
- Most patients with skin cancer develop non-melanoma skin cancer.
- This group of cancers includes basal cell carcinoma, the most common neoplasm worldwide, and squamous cell carcinoma.
- Fortunately, mortality associated with non-melanoma skin cancer is unusual.
- However, malignant melanoma accounts for 75 percent of all deaths associated with skin cancer.
- Melanoma, the eighth most common malignancy in the United States, is the cancer with the most rapidly increasing incidence.
- 1 of 1,500 Americans born in 1935 were likely to develop melanoma, compared with 1 of 105 persons born in 1993.
- Non-melanoma skin cancer typically affects older persons; the frequency of melanoma peaks between 20 and 45 years of age.
- Mortality rates are higher in men than in women.
- This higher rate may occur because lesions tend to develop in less easily observed areas, such as the back, in men.
- Mortality is also increased in blacks for this reason, as is the propensity to develop more aggressive tumors and to be diagnosed at later stages.
- The rising incidence of skin cancer over the past several decades may be primarily attributed to increased sun exposure associated with societal and lifestyle changes and to depletion of the protective ozone layer.
Prevention of Skin Cancer
- Avoid the sun during peak hours.
- Generally, this is between 10 a.m. and 4 p.m.
- Water, snow, sand and concrete reflect light and increase the risk of sunburn.
- Wear sun protective clothing.
- This includes pants, shirts with long sleeves, sunglasses and hats.
- Use sunscreen.
- Look for water-resistant, broad-spectrum coverage with an SPF of at least 30, which blocks 97 percent of the sun’s UVB rays.
- Apply sunscreen generously, and reapply every two hours — or more often if you’re swimming or sweating.
- Higher-number SPFs block slightly more of the sun’s UVB rays, but no sunscreen can block 100 percent of the sun’s UVB rays.
Screening for Skin Cancer
- While early detection and treatment of skin cancer can improve patient outcomes, convincing data regarding the benefit of mass screening programs are lacking.
- In addition, the ability to identify potentially malignant lesions varies with physician training.
- So, except for very high-risk persons with a history of skin cancer or atypical mole syndrome, for whom periodic screening is universally recommended, there is considerable debate about who should be screened, who should perform the screening and how often screening should be performed.
- Part of the screening process should include an assessment of patient risk.
- Basically,
- Age 20 to 39 years: complete skin examination every three years
- Age 40 years and older: annual complete skin examination
- When screening is performed, the examiner must systematically inspect the entire skin surface.
- The patient should completely disrobe and remove concealing cosmetics.
- Daylight is the ideal light source
- Photographs may improve the quality of documentation and detection of lesion changes over time.
- ABCDE Rule:
- Asymmetry (one half of the mole doesn’t match the other),
- Border irregularity,
- Color that is not uniform,
- Diameter greater than 6 mm (about the size of a pencil eraser), and
- Evolving size, shape or color.
Specific Skin Neoplasms
ACTINIC KERATOSES
- Actinic keratoses, sometimes called solar keratoses, often arise on chronically sun-damaged body areas such as the face, ears, arms and hands.
- They may provide an indication of a person’s cumulative ultraviolet light exposure and, therefore, that person’s risk for all types of skin cancer.
- Actinic keratoses are often ill-defined and irregular, ranging from 1 mm to several centimeters in size.
- They may be lesions that can be seen or felt, and generally have a scaly appearance.
- Patients often have multiple lesions.
- The lesions are usually pale brown or flesh-colored but may be yellow, reddish-brown or even dark brown or black following trauma.
- The rate of malignant transformation of individual actinic keratoses to squamous cell carcinoma is less than one per 1,000 per year,
- but treatment of lesions is indicated to decrease the chance of progression to squamous cell carcinoma.
- Skin biopsy is occasionally required to rule out squamous cell carcinoma.
- Cryotherapy with liquid nitrogen is the treatment of choice for most cases of actinic keratosis.
- Curettage, or scraping away the lesion, may also be used and may be used in conjunction with cryosurgery or electrodessication (burning).
- Surgical excision is rarely required but may be useful in excluding squamous cell carcinoma as a possible cause in lesions that are larger than 0.5 cm in diameter.
- Chemical destruction of superficial lesions may be used when there are many lesions, particularly on the face and head.
- 5-fluorouracil (5-FU), is most commonly used.
- Areas other than the head and neck require the higher concentrations because of greater skin thickness.
- In conventional regimens, 5-FU is applied twice daily for two to five weeks.
- Adverse effects include true hypersensitivity, secondary bacterial and herpetic infection, and post-inflammatory pigmentation changes.
- This therapy is often associated with significant discomfort related to an intense inflammatory response.
- Pulsed dosing regimens aimed at reducing skin irritation have met with mixed success.
- Topical corticosteroids may reduce inflammation but also make the treatment end point difficult to discern.
- Other therapies used occasionally for treatment of actinic keratoses include laser, topical Retin-A, chemical peeling and facial dermabrasion.
BASAL CELL CARCINOMA
- Basal cell carcinoma is the most common skin neoplasm.
- Basal cell carcinomas
- are usually located on the face or the backs of the hands.
- They typically grow slowly and generally spread only locally.
- Metastasis is quite rare.
- While a preliminary diagnosis of basal cell carcinoma may be made on the basis of appearance, incisional or excisional biopsy is required for definitive diagnosis.
- Cure rates of 95 to 99 percent can be achieved for low-risk lesions using simple excision with margins of 2 to 5 mm.
- A lesion is considered low risk if it is less than 1.5 cm in diameter; has not previously been treated; is not in a difficult-to-treat area, like the H zone of the face; and is nodular or cystic.
- Treatment of basal cell carcinomas with cryotherapy can also be successful, but healing may take weeks, and success depends on the skill of the cryotherapist.
- Mohs’ micrographic surgery is the treatment of choice for most sclerosing basal cell carcinomas, as well as for large tumors and those located in areas that are difficult to treat.
- Radiation therapy produces cure rates of 90 to 95 percent but has the same limitations as those outlined for squamous cell carcinoma treatment.
- Other therapies used occasionally include topical Retin-A.
- Basal cell carcinomas
SQUAMOUS CELL CARCINOMA
- Squamous cell carcinoma is the second most common skin cancer, comprising 20 percent of all cases of non-melanoma skin cancer.
- This is the most common tumor in elderly patients, and it is usually the result of a high lifetime cumulative dose of solar radiation.
- A new study finds that some types of human papillomaviruses, or HPVs, may increase the risk of squamous cell skin cancers.
- However, other irritants and exposures may lead to squamous cell carcinoma.
- Up to 60 percent of squamous cell carcinomas occur at the site of a previous actinic keratosis.
- Changes in an actinic keratosis that suggest evolution to squamous cell carcinoma include pain, erythema, ulceration, induration, hyperkeratosis and increasing size.
- As many as 50 to 60 percent of squamous cell carcinomas occur on the head and neck.
- Other common sites include the hands and forearms, upper trunk and lower legs.
- Squamous cell carcinomas typically appear as small, palpable tumors that may grow moderately rapidly over a period of months and range from a few millimeters to centimeters in size.
- They may appear nodular, and may be reddish-brown, pink or flesh-colored.
- Larger squamous cell carcinomas may appear crusted, erythematous or eroded. In contrast to basal cell carcinoma, a definitive edge is difficult to demonstrate when a squamous cell carcinoma lesion is stretched.
- This is the most common tumor in elderly patients, and it is usually the result of a high lifetime cumulative dose of solar radiation.
- Histologic confirmation by a full-thickness skin biopsy (incisional or excisional) is mandatory before definitive treatment.
- Well-differentiated lesions less than 2 cm in diameter can be treated with surgical excision, with a cure rate approaching 99 percent.
- Squamous cell carcinomas may grow aggressively and are associated with a 2 to 6 percent risk of metastasis.
- Risk factors for metastasis include increasing lesion depth and location on the lip or ear.
- The most common locations for metastatic spread are the regional lymph nodes, lungs and liver.
- Once metastasis occurs, the five-year cure rate for squamous cell carcinoma is 34 percent.
- Recurrence and metastasis typically occur within three years of initial treatment.
- Mohs’ micrographic surgery involves gradual lesion excision using serial frozen section analysis and precise mapping of excised tissue until a tumor-free plane is reached.
- Mohs’ micrographic surgery is used when tissue removal must be kept to a minimum for cosmetic reasons or to maximize function.
- It is the treatment of choice for difficult and high-risk squamous cell carcinomas, including lesions that are:
- larger than 2 cm in diameter;
- located in areas where deep invasion is more likely or tumor extent is hard to assess, such as the nasolabial folds, eyelids and periauricular areas (facial “H zone”);
- rapidly growing;
- recurrent or incompletely excised;
- ill-defined;
- located in an area of previous irradiation; or
- Cure rates of 99 percent have been reported.
- Cryotherapy and the combination of curettage and desiccation are reserved for treatment of superficial tumors, lesions less than 2 cm in diameter and lesions located on the trunk and extremities.
- Radiation therapy may be employed when preservation of function and cosmesis are critical, when patients refuse surgery, when metastasis is present or when an adjunct to surgery is required for high-risk tumors.
- Because of the long-term risk of radiation-induced carcinoma, radiation therapy is used only in patients older than 60 years.
MALIGNANT MELANOMA
- There are four types of malignant melanoma.
- The two most common ones are:
- The superficial spreading type is the most common among whites and accounts for 70 percent of all melanomas.
- It usually occurs in adults and may develop anywhere on the body but appears with increased frequency on the upper backs of both men and women and on the legs of women
- The superficial spreading type is the most common among whites and accounts for 70 percent of all melanomas.
- Nodular melanoma (accounting for 15 to 30 percent of all melanomas) is a dome-shaped, pedunculated or nodular lesion that may occur anywhere on the body.
- It is commonly dark brown or reddish brown but may occasionally be uncolored.
- Nodular melanomas tend to rapidly invade the dermis from the onset with no apparent horizontal growth phase.
- These tumors are frequently misdiagnosed, because they may resemble blood blisters, hemangiomas, dermal nevi or polyps
Bottom Line on Skin Cancer
- The incidence of skin cancer is increasing by epidemic proportions.
- The use of tanning beds the risk of basal cell carcinoma by 1.5 times and squamous cell carcinoma by 2.5 times.
- Basal cell cancer remains the most common skin neoplasm, and simple excision is generally curative.
- Squamous cell cancers may be preceded by actinic keratoses – premalignant lesions.
- While squamous cell carcinoma is usually easily cured with local excision, it may invade deeper structures and metastasize.
- Aggressive local growth and metastasis are common features of malignant melanoma, which accounts for 75 percent of all deaths associated with skin cancer.
- Early detection greatly improves the prognosis of patients with malignant melanoma.
- The differential diagnosis of pigmented lesions is challenging, although the ABCD (Asymmetry, Border, Color, Diameter) checklists are helpful in determining which pigmented lesions require excision.
- Sun exposure remains the most important risk factor for all skin neoplasms.
- Thus, patients should be taught basic “safe sun” measures: sun avoidance during peak ultraviolet-B hours; proper use of sunscreen and protective clothing; and avoidance of sun tanning.
[Thanks to the American Academy of Family Physicians for much of the information provided in this episode.]