Invasive squamous cell carcinoma is a type of cancer that occurs in the flat cells that make up the outer layer of skin and the linings of some organs, known as squamous cells. In this case, the word invasive means that the cancerous tumor has penetrated deeply into the skin or organ, as opposed to remaining a surface lesion. For example, in cases of invasive squamous cell carcinoma of the skin, the tumor may have penetrated into the dermis through the epidermis. Depending on the location, size, and severity of the tumor, there are several different courses of treatment that may be pursued.
Squamous cell carcinoma is the second most common type of skin cancer after basal cell carcinoma. Most often it is caused by exposure to UV rays, either through natural sunlight or by indoor tanning. People with fair skin are particularly susceptible. It can also occur in organs as diverse as the prostate, bladder, and larynx, although these are nowhere near as common as squamous cell skin cancer. Exposure to radiation or chemical carcinogens, as well as some inflammatory or scarring disorders, can also increase the risk of squamous cell cancer.
Invasive squamous cell carcinoma can be serious because of the risk of cancer metastasis, which means the cancer spreads to other areas of the body or additional organ systems. This risk of metastasis is higher with invasive lesions than it is with shallow lesions. Risk increases if the tumor is large, very deep, or if it is close to other systems such as the lymph nodes or nerves. Some patient characteristics can also influence this risk, such as poor immune system functioning.
Most of the time, this condition is treated by surgically removing the tumor, which is usually curative. A specialized surgical technique precisely determines the boundaries of a tumor, called Mohs micrographic surgery, may be used for irregularly shaped or potentially disfiguring lesions. If a tumor is considered high risk because of its location, depth, size, or tumor features, radiation therapy may be needed to make sure that all of the cancer is removed or destroyed. Chemotherapy may be needed if the cancer has metastasized, but this treatment is unlikely if the tumor has spread.
Patients who have had one invasive squamous cell carcinoma are at a higher risk of developing others. It is important to closely monitor any changes in the skin, and to avoid unprotected sun exposure. Regular visits to a dermatologist for a full skin check will also help to ensure that any future tumors can be caught quickly, which will make treatment easier and more likely to be successful.