What is skin cancer?
Skin cancer is a common and locally destructive cancerous (malignant) growth of the skin. It originates from the cells that line up along the membrane that separates the superficial layer of skin from the deeper layers. Unlike cutaneous malignant melanoma, the vast majority of these sorts of skin cancers have a limited potential to spread to other parts of the body (metastasize) and become life-threatening.
There are three major types of skin cancer:
- basal cell carcinoma (the most common) and
- squamous cell carcinoma (the second most common), which originate from skin cells, and
- melanoma, which originates from the pigment-producing skin cells (melanocytes) but is less common, though more dangerous, than the first two varieties.
What are the risk factors for skin cancer?
The most common risk factors for skin cancer are as follows.
- Ultraviolet light exposure, either from the sun or from tanning beds. Fair-skinned individuals, with hazel or blue eyes, and people with blond or red hair are particularly vulnerable. The problem is worse in areas of high elevation or near the equator where sunlight exposure is more intense.
- A chronically suppressed immune system (immunosuppression) from underlying diseases such as HIV/AIDS infection or cancer, or from some medications such as prednisone or chemotherapy
- Exposure to ionizing radiation (X-rays) or chemicals known to predispose to cancer such as arsenic
- Certain types of sexually acquired wart virus infections
- People who have a history of one skin cancer have a 20% chance of developing a second skin cancer in the next two years.
- Elderly patients have more skin cancers.
An infant with an ear infection may seem fussier than usual, especially when lying down, as this puts pressure on the ear. Your baby’s eating and sleeping habits may also change. Pulling and tugging on the ear can also be a sign of a chronic ear infection in infants. However, this can also be caused by teething or exploration of the body.
What causes skin cancer?
It appears basal cell skin cancers arise from DNA mutations in the basaloid cells in the upper layer of the skin. Many of these early cancers seem to be controlled by natural immune surveillance, which when compromised may permit the development of masses of malignant cells that begin to grow into tumors.
In squamous cell cancers, the tumors arise from normal squamous cells in the higher layers of the skin of the epidermis. As with basal cell cancers, these cells are prevented from growing wildly by natural mutational repair mechanisms. When there is an alteration in these genes or the immune surveillance system that controls it, these skin cancers start to grow. In most instances, the genes are altered by ultraviolet exposure.
What is the treatment for skin cancer?
There are several effective means of treating skin cancer. The choice of therapy depends on the location and size of the tumor, the microscopic characteristics of the cancer, and the general health of the patient.
- Topical medications: In the case of superficial basal cell carcinomas, some creams, gels, and solutions can be used, including imiquimod (Aldara), which works by stimulating the body's immune system causing it to produce interferon which attacks the cancer, and fluorouracil (5-FU), a chemotherapy drug. Some patients do not experience any side effects of these topical treatments, but others may have redness, inflammation, and irritation. A drawback of topical medications is that there is no tissue available to examine to determine if a tumor is removed completely.
- Destruction by electrodessication and curettage (EDC): The tumor area is numbed with a local anesthetic and is repeatedly scraped with a sharp instrument (curette), and the edge is then cauterized with an electric needle. The advantage of this method is that it is fast, easy, and relatively inexpensive. The disadvantages are that the scar is often somewhat unsightly, and the recurrence rate is as high as 15%.
- Surgical excision: The area around the tumor is numbed with a local anesthetic. A football-shaped portion of tissue including the tumor is then removed and then the wound edges are closed with sutures. For very big tumors, skin grafts or flaps are needed to close the defect. The advantages of this form of treatment are that there is a greater than 90% cure rate, the surgical specimen can be examined to be sure that the whole tumor is successfully removed, and the scar produced is usually more cosmetically acceptable than that of the EDC procedure. It is a more complicated procedure and is more expensive than EDC.
- Mohs micrographic surgery: The site is locally anesthetized and the surgeon removes the visible tumor with a small margin of normal tissue. The tissue is immediately evaluated under a microscope and areas that demonstrate residual microscopic tumor involvement are re-excised and the margins are re-examined. This cycle continues until no further tumor is seen. This more complicated and expensive option is the treatment of choice for tumors where normal tissue preservation is vital, where the tumor margins are poorly defined, in tumors that have been previously treated and have recurred, and in certain high-risk tumors.
- Radiation therapy: Ten to fifteen treatment sessions deliver a high dose of radiation to the tumor and a small surrounding skin area. This form of treatment is useful in those who are not candidates for any surgical procedure. The advantage of radiation therapy is that there is no cutting involved. The disadvantages of this expensive alternative are that the treated area cannot be tested to be sure the whole tumor is gone and radiation scars look worse over time. It is for this reason it is usually reserved for elderly patients.
- Other types of treatments for skin cancers include cryosurgery where tissue is destroyed by freezing, photodynamic therapy (PDT) in which medication and blue light is used to destroy the cancerous tissue, laser surgery to vaporize (ablate) the skin's top layer and destroy lesions, and oral medications vismodegib (Erivedge) and sonidegib (Odomzo).