Carcinoma is the most common type of cancer. It begins in the epithelial tissue of the skin, or in the tissue that lines internal organs, such as the liver or kidneys.

Carcinomas may spread to other parts of the body, or be confined to the primary location. The disease has various forms, including:

Carcinoma in situ: This early-stage cancer is confined to the layer of tissue from which it started, and has not spread to surrounding tissue or other parts of the body
Invasive carcinoma: This is cancer that has spread beyond the primary tissue layer to surrounding tissue.
Metastatic carcinoma: This is cancer that has spread throughout the body to other tissues and organs.

Types of carcinoma

Carcinomas may occur in many parts of the body. Some common types of carcinoma include:

Basal cell carcinoma is the most common type of skin cancer. Cancerous cells develop in the basal cell layer of the skin, or the lowest part of the epidermis. Basal cell cancers usually grow slowly, and they rarely spread, or metastasize, to nearby lymph nodes or more distant parts of the body.

Squamous cell carcinoma is the second most common type of skin cancer. Cancerous cells develop from the flat, squamous cells that are the primary cell type making up the outermost layer of the skin, the epidermis. Squamous cell cancers usually grow slowly, and it is uncommon for them to spread, or metastasize, but they are more likely than basal cell carcinomas to invade fatty tissue beneath the skin or to spread even further.

Renal cell carcinoma is the most common type of kidney cancer. The cancerous cells typically develop in the lining of very small tubes in the kidney, called tubules. Over time, these cells may grow into a mass and cause an obstruction. The cancer may form in one or both kidneys.

Ductal carcinoma in situ is the most common type of breast cancer. Cancerous cells are confined to the lining of the milk ducts, and haven’t spread through the duct walls into surrounding breast tissue.

Invasive ductal carcinoma occurs when cancerous cells grow in the duct lining, break through the wall of the duct and invade local breast tissue. From there, the cancer may spread, or metastasize, to other parts of the body.

Carcinoma treatment and therapy options

Treatment for carcinoma varies depending on the type, location and extent of the disease, but may include:

Surgery: Depending on the type of cancer, carcinoma may be treated with the surgical removal of cancerous tissue, as well as some surrounding tissue. Minimally invasive surgical treatment methods may help to reduce healing time and reduce the risk of infection after surgery.

Radiation therapy: Radiation therapy may be used in combination with surgery and/or chemotherapy. Advanced radiation therapies use image guidance before and during treatment on target tumors, and are designed to help spare healthy tissues and surrounding organs.

Chemotherapy: Chemotherapy treats carcinoma with drugs designed to destroy cancer cells, either throughout the whole body, or in a specific area. In some cases, chemotherapy may be used in combination with other treatments, such as radiation therapy or surgery.