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Squamous Cell Carcinoma - Patient Information

What is squamous cell carcinoma?

Squamous cell carcinoma (SCC) is a skin cancer arising from cells of the top layer of the skin (epidermis) which can spread to other parts of the body. It is the second most frequent malignant skin tumor after basal cell carcinoma.

Who is at risk for squamous cell carcinoma and how common is it?

Melanoma and nonmelanoma (basal and squamous cell carcinoma) skin cancer are now the most common type of cancer in the Caucasian population and the incidence of skin cancer has reached epidemic proportions. Many epidemiological studies have demonstrated that the incidence of skin cancer has been increasing rapidly over the last decades. Nonmelanoma skin cancers (NMSCs) constitute more than one-third of all cancers in the United States with an estimated incidence of over 600,000 cases per year. NMSCs are the most common malignancies occurring in the Caucasian population each year. Of these 600,000 cases approximately 500,000 are basal cell carcinomas (BCCs) and 100,000 to 150,000 are squamous cell carcinomas (SCCs). The standardized ratio of BCC to SCC is roughly 4 to 1. The incidence of NMSC (BCC and SCC) is 18 times greater than that of malignant melanoma. However, incidence data of high epidemiological quality on NMSC are sparse because traditional cancer registries often exclude NMSC or are at least incomplete. Miller & Weinstock (1994) estimated the 1994 NMSC incidence in the United States to be between 900,000 and 1,200,000. The lifetime risks were estimated to be 28% to 33% for BCC and 7% to 11% for SCC (lifetime risk of developing NMSC for a child born in 1994)

BCC represents 75% of NMSC and is, therefore, the most common malignant disease throughout the world. Silverberg et al (1990) estimated the average annual incidence of BCC in the United States to 191 new lesions per 100,000 white persons According to the estimates (lowest and highest estimated incidence rates) of Miller & Weinstock (1994) the age-adjusted incidence rates per 100,000 whites per year (1994) in the United States were as follows: BCC (men) 407–485, BCC (women) 212–253), SCC (men) 81-136, SCC (women) 26-59). For South Wales (United Kingdom) the age-standardized (world standard population) incidence rates per 100,000 population in 1998 were lower: BCC (men) 127.9, BCC (women) 104.8, SCC (men) 25.2, SCC (women) 8.6 (Holme et al. 2000). Although these incidence rates are high, they do not approach the rates described from Australia. The incidence is 1% to 2% per year (1000 to 2000 per 100,000 per year): Townsville, Australia (Buettner et al. 1998): BCC (male) 2058, BCC (female) 1195, SCC (male) 1332, SCC (female) 755); Nambour, Australia Green et al. 1996): BCC (male) 2074, BCC (female) 1579, SCC (male) 1035, SCC (female) 472.

There is an increased risk of NMSC in whites, especially those who have blue eyes, a fair complexion, sunburn easily, suntan poorly, freckle with sun exposure, have red, blond, or light-brown hair (Celtic ancestry). NMSC is uncommon in blacks, Asians, and Hispanics. There is a higher incidence of BCC in Albino blacks than in normally pigmented blacks. Compared with whites, blacks have a decreased risk of BCC on sun-exposed areas, but the same incidence of BCC on covered skin. In contrast to whites, sunlight does not appear to be an important etiologic factor for SCC in blacks because lesions occur on non-sun-exposed regions of the body. SCC in blacks arise most often on sites of preexisting inflammatory skin conditions, burn injuries, or trauma. SCC in blacks are often seen in scars, burns, or ulcers.

The incidence of NMSC is increasing rapidly. In white populatOnce an individual develops a NMSC, there is a 36%-52% chance that a new skin cancer will appear within 5 years.ions in Europe, the United States, Canada, and Australia the average increase of NMSC was 3-8%. Chronic sun exposure is the main cause of NMSC. Over 80% of NMSCs occur on areas of the body that are frequently exposed to sunlight, such as head, neck, and back of the hands. BCC is also most commonly found on the nose. The rising incidence rates of NMSC is probably due to a combination of increased sun exposure or exposure to ultraviolet light, increased outdoor activities, changes in clothing style, increased longevity, and ozone depletion. In incidence of NMSC in Caucasians increases proportionally with proximity to the equator, with the incidence of SCC doubling for each 8-10 degree decline in latitude. UV dosage per unit time at the equator in the Pacific is very high, about 200% that of Europe or the northern US, and 30% higher than that of the southern US. The incidence of NMSC is elevated in individuals with a high cumulative exposure to UV light, such as outdoor workers, or those with more frequent outdoor activities. The incidence is also increasing with age: According to Holme et al. (2000) in 1998 the incidence of BCC in individuals over 75 years old was approximately 5 times higher compared to individuals between 50 and 55 years old, and for SCC approximately 35 times higher. The incidence of SCC increases more rapidly with age than does BCC. The reported increases in the incidence of melanoma and NMSC have partially been attributed to a larger amount of UVB radiation reaching the surface of the earth as a result of ozone depletion in the atmosphere. The ozone layer has decreased by approximately 2% over the past 20 years. A 2% decrease in ozone concentration will increase biologically effective radiation from the sun by approximately 4%. It was estimated that this additional UV radiation will cause a 6-12% increase in NMSC in exposed populations.

Once an individual develops a NMSC, there is a 36%-52% chance that a new skin cancer will appear within 5 years.

What causes squamous cell carcinoma and how does it develop?

There are several factors known to cause squamous cell carcinoma. Probably the most important factor is the genetically defined individual skin type. People with fair or sun-sensitive skin, with red hair and many freckles are at risk of developing squamos cell carcinoma. Next to the genetic factor the accumulatedexposure to the sun's UV-radiation during one's lifetime has been proven to be responsible for this type of skin cancer since the majority of squamous cell carcinomas appear on sun-exposed areas such as the face, lower lip, neck, ears, and hands.

Squamous cell carcinoma can also emerge from continuous exposure to chemical cancer-causing substances (chemical carcinogens) such as tars, oils, and arsen. A further factor that may increase the risk of developing this particular skin cancer is the presence of chronically injured skin. Squamous cell carcinoma usually does not occur on healthy skin. Scars from burning or constantly inflamed skin areas can be risk afflicted conditions.

Also patients who have to undergo immunesuppressive treatment due to a organ transplantation, people with an inherent immune defect or AIDS-patients carry an increased potential of developing squamous cell carcinoma. This applies as well to people who are infected with the human pappiloma virus (HPV) which is a virus known to cause warts or malignant disorders.

The presence of squamous cell carcinoma is rather of architectural nature than of cellular nature. Squamous cell carcinoma is present when abnormal cells (keratinocytes) of the top layer of the skin (epidermis) reach the layer below (dermis) and invade it.

How to spot squamous cell carcinoma

The affected area has to be carefully examined by a dermatologist. The appearance of squamous cell carcinoma can vary greatly and has to be distinguished from other skin disorders. But usually the recognition of squamous cell carcinoma by a dermatologist is quite easy. In case there is any doubt a piece of the lesion sometimes must be removed for further examination (biopsy).

What does it look like?

SCC usually begins as a small wart-like lesion of grey or yellow-brownish color. At first it grows slowly and painlessly but when it reaches a certain size it may start growing rapidly and destructively. It can also spread to other parts of your body. Remember that SCC sometimes grows like an iceberg – hiding the largest part under the skin’s surface. Therefore if you have a suspicious area of skin you should watch it closely and have it checked by your dermatologist or physician.

How to prevent squamous cell carcinoma

The best way to avoid getting SCC is protecting yourself from UV radiation, make sure to get treatment for chronic skin changes (rough and damaged areas), and avoid long-term heat exposure as well as cancer causing chemicals, such as tars (stop smoking), oils, and arsen.

Is it really Squamous Cell Carcinoma?

There are many skin diseases that may look similar to SCC. Just because you have a rough spot on your skin does not mean you have cancer, yet it is something that should be taken seriously. If you have noticed a strange looking area of skin please see your dermatologist or doctor.

What could go wrong?

A squamous cell carcinoma can cause major disfigurement if it is not caught early. The area where the cancer is found is also prone to infection; it is a weak spot in the skin, which normally serves as a protective barrier against germs and viruses. The cancer may even turn into a large open sore. Like other forms of cancer squamous cell carcinoma can spread to other parts of the body.

I have squamous cell carcinoma what can I do?

There are several effective treatment options available for squamous cell carcinoma. To decide which one will be the most appropriate depends very much on the individual case and should be discussed with your physician.
Moh´s Surgery / Surgery
Surgery is the most effective treatment. The tumor will be excised and the wound will be closed with a few stitches (amount depending on size of affected area). Surgery always requires a local anaesthetic. Usually the wound will heal within two weeks. Moh´s surgery is a special type of surgery where the surgeon is specially trained. During the surgery a microscopic method is used to make sure all of the affected skin areas are excised. This type of surgery is rather complicated but has a high cure rate.

Advantages of the treatment

It has the highest cure rate of all surgical treatments.
The removed tissue can be examined microscopically to determine if the tumor has been totally excised.

Disadvantages of the treatment

There are local anesthetics required.
It is a rather complicated proceedure.

Cryosurgery
Here liquid nitrogen is applied to the affected surface with a cotton tip applicator or spray device. Liquid nitrogen is extremely cold (-195,8 °C = -320,44 °F) and will cause death of all cells of this area. Unfortunately there is no control as to how deep the tissue has been destroyed. Therefore reoccurences are not uncommon.

Advantages of the treatment

It usually is an effective treatment.
It is a quick procedure.
It only requires one or two visits to the doctor.
In general it is a rather cheap treatment. (?)

Disadvantages of the treatment

The treatment causes discomfort and/or pain.
Due to freezing the skin may presumably react with blisters, reddening, swelling or a change of color in skin patches.
An infection may occur due to delayed wound-healing.
There is a risk of scarring.

Curettage
Curettage describes the scraping away of a superficial skin disorder. Usually a scalpel or another sharp device, called a curette, is used for scraping. Unfortunately there is no control if all of the affected tissue has been removed. Therefore reoccurances are not uncommon.

Advantages of the treatment

It usually is an effective treatment.

Disadvantages of the treatment

The treatment usually requires a local anesthetic.
Occasionally, a change of color or an infection of the skin may occur.
There is a possibility of scaring.

Radiotherapy
This therapy uses X-rays to destroy damaged cells. Usually the affected area needs to be treated several times to reach a dose that is effective, depending on the size and stage of the squamous cell carcinoma. Therefore the therapy might last several weeks.

Advantages of the treatment

This treatment has a good cure rate.
It is good for elderly patients who are not physically able to undergo surgery.

Disadvantages of the treatment

There is a risk of scarring.
There are several treatment sessions required.

Other Treatments
Laser
Affected cells are destroyed by the laser.

Interferon alfa
Interferon alpha is not yet an approved treatment for squamous cell carcinoma, although at the moment there are ongoing trials with interferon alpha for treating squamous cell carcinoma. Usually it is injected directly into the affected area and should support the immune defense system. Unfortunately this therapy is connected with several disturbing side effects e.g. flu-like symptoms such as fever, drowsiness and nausea. Sometimes it may also cause a reduction of white, sometimes even red blood cells.

What are the chances of being cured?

The cure rates depend on the size and aggressiveness. Usually the cure rates for squamous cell carcinomas of 2 - 3 cm in diameter is about 90 %. Of course the more advanced a squamous cell carcinoma is, the worse the cure rates will be. Therefore do not hesitate if you have a suspicious area on your skin: go see a dermatologist or physician to be certain.

The risk of the carcinoma spreading to other parts of the body depends on the site where it occurred. The risk of spreading varies from 1 to 50%. Squamous cell carcinomas that appear on the lip, ears and palm or sole have a high potential for spreading.