The incidence of global skin cancer (melanoma and non-melanoma) has been increasing for the past decades. Malaysia’s officially published National Cancer Registry data, reported that skin cancers account for 2.6% of cancer cases in the country.
There are 2 major types of skin cancers:
- Non-melanoma – including basal cell carcinoma and squamous cell carcinoma
- Melanoma – can be highly lethal due to high risk of spread
Other important types of skin cancer include:
- Cutaneous lymphoma
- Kaposi sarcoma
- Merkel cell carcinoma
Skin cancer is a 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 skin cancers have a limited potential to spread to other parts of the body (metastasize) to become life-threatening.
Both forms of skin cancer may appear as a sore that bleeds, oozes, crusts, or otherwise will not heal. They begin as a slowly growing bump on the skin that may bleed after minor trauma. Both kinds of skin cancers may have raised edges and a central ulceration.
Basal cell carcinomas (BCC) is also known as rodent ulcer. This is an abnormal uncontrolled growth of cells that arise in the skin’s basal cells, which is the deepest layer of the epidermis (the outemost later of the skin). BCC is the most frequently occurring skin cancer, and almost never metastasize beyond original tumour size except in extremely rare cases. It shouldn’t been taken lightly though, as it can be disfiguring if not treated promptly. Some features of BCC include:
- Usually painless
- Appearance of a shiny pink, red, pearly, or translucent bump
- Pink skin growths or lesions with raised borders that are crusted in the center
- Raised reddish patch of skin that may crust or itch, but is usually not painful
- A white, yellow, or waxy area with a poorly defined border that may resemble a scar
Squamous cell carcinomas (SCC) may be painful.
- Persistent, scaly red patches with irregular borders that may bleed easily
- Open sore that does not go away for weeks
- A raised growth with a rough surface that is indented in the middle
- A wart-like growth
A skin examination by a dermatologist is the way to get a definitive diagnosis of skin cancer. In many cases, the appearance alone is sufficient to make the diagnosis.
A skin biopsy is usually used to confirm a suspicion of skin cancer. This is performed by numbing the area under the tumor with a local anesthetic such as lidocaine. A small portion of the tumor is sliced away and sent for examination by a pathologist, who looks at the tissue under a microscope and renders a diagnosis based on the characteristics of the tumor.
There is no specific staging system for basal cell carcinoma. If the tumor is wider than 2 cm (about ¾ inch diameter), it is probably a more serious tumor. BCC of the ears, nose, and eyelid may also be of more concern, regardless of the size.
There is a staging system for squamous cell carcinoma. Large tumors that are thicker than 2 mm, invade the nerve structures of the skin, occur on the ear, and have certain worrisome characteristics under the microscope are of more concern. If the tumor metastasizes to a site at some distance from the primary tumor, the cancer is likely to be a dangerous tumor.
There are several effective means of treating skin cancer. The choice of therapy depends on:
- the type of skin cancer
- how far it’s grown or spread
- stage of cancer (if relevant)
- the general health of the patient.
This is the main treatment for skin cancer. This may be the only treatment needed. A skin graft may be needed to covers removal of a large area or depending on where the cancer is located in the body.
There are different types of surgery depending on the where the cancer and how big it is. Examples are excisional biopsy, cryosurgery, laser surgery, curettage and electrocautery or Mohs microsurgery.
This is a treatment for basal cell carcinoma or squamous cell carcinoma. This treatment may be recommended if:
- Cancer affects a large area
- Cancer in difficult to operate on
- Surgery not suitable for example in an elderly patient
- To reduce risk of cancer returning after surgery
- Cancer beyond nodes
In the case where skin cancers are only on the top layer of the skin, creams, gels, and solutions can be used. Chemotherapy creams such as fluorouracil can be used on actinic or solar keratosis to prevent development into squamous cell carcinoma.
If cancer has spread, chemotherapy may be recommended.
A new class of drugs that teaches the body immune system to attack cancer cells such as checkpoint inhibitors are now replacing chemotherapy as the standard treatment for melanoma. These can be used in combination and has been shown to extend lives.