SCC’s develop in several different circumstances and vary greatly as to how dangerous they are. Like other forms of cancer, such as cervical and colon, they may be closer to pre-cancerous, highly malignant or somewhere in between. Most develop out of actinic keratoses (rough sun spots), some from old wounds, and some due to a weakened immune system.

The most common types of SCC are Bowens disease ("SCC in situ") and Keratoacanthoma. These types are only rarely a threat, but could develop into a more dangerous type if not treated promptly. At times, aggressive SCC will be found that looked like a different type of skin cancer, so only a biopsy can determine what the risk is with certainty.

Bowens disease looks like a dry rough patch. Prior to seeing a dermatologist, it is often thought to be a fungus or rash. Keratoacanthoma is a rapidly forming lump with a central dry core. It is frequently thought to be a "boil" or cyst before evaluation. The risk of metastasis is probably under 1%.

SCC that are invasive are more dangerous. They most commonly appear as a lump, and are often open sores that bleed easily. The risk of metastasis is around 3%. Some of these may be considered high risk because of size, location or features seen on the biopsy. They may be found on the ear, lip or in an old wound. They are larger, deeper, and may invade nerves or have cell that are "poorly differentiated". The risk of metastasis from a high risk SCC runs from 10 to 30%.

The treatment for an SCC depends on its type, location and risk. For most SCC the best treatment is excision (the SCC is cut out and the hole stitched up). Along with a surrounding strip of normal appearing skin, this is sent to a pathology laboratory. The lab checks to confirm complete removal complete removal of the SCC. Small, surface SCC can also be destroyed by freezing (cryosurgery) or curettage and electrodesiccation (C &E). Cryosurgery uses liquid nitrogen for small superficial lesions, while C & E removes the SCC by scraping of the tumor and cauterizing the base. It usually requires less visits to complete and the wound usually heals rapidly without needing stitches.

High-risk tumors are best treated by wide excision (removal of a large margin of normal skin) or Mohs' Surgery. Mohs surgery is a specialized microscopically controlled surgical technique that removes the entire tumor, and only the tumor. It has the highest cure rate, and is the least disfiguring. If used on larger cancers or on a difficult site a plastic surgeon may also be needed to repair the defect left after excision. Mohs surgery should almost always be used if the SCCs comes back at the same site (recurs).

Radiation therapy (X-ray treatment) may be added after surgery of a high-risk SCC. It can add measurably to the cure rate. It is probably used less often than it should be. Occasionally, radiation is used as the sole treatment in inoperable tumors, or in those that have already spread. Oncologists are not normally involved in the treatment of ordinary SCC. If the SCC spreads one will be needed to give chemotherapy. This is only used for advanced disease.

Once you have developed one SCC, you are always at risk of developing another one. The actinic keratoses on your skin are the breeding ground for future SCC and these should be treated. You may also be at risk for other forms of skin cancer. Regular dermatology examinations, at least twice yearly, will be needed for at least 2 years.

The best way to avoid developing more skin cancers is to protect your skin from further sun damage. Use sunscreen of at least SPF15 and wear a broad brimmed hat. Eat a healthy, low fat diet, Early treatment of SCC makes treatment easier, so learn the signs of skin cancer, and check your skin once each month. Promptly seek care for any suspicious growths