Lip cancer is an uncommon type of oral cancer that can arise from the lining or the skin of the lips.

What is lip cancer?

Lip cancer is a relatively rare type of oral cavity cancer. Just 0.7 out of every 100,000 adults in the United States are diagnosed each year. Overall, 0.1% of people will be diagnosed with lip cancer in their lifetime.

There are several types of cancer that can arise from the lip:

Squamous Cell Carcinoma

The most common kind of lip cancer is squamous cell carcinoma. It affects the squamous cells, which are found in the surface of the skin and the lining of the digestive tract, including the mouth. More than 90% of lip cancers are squamous cell carcinomas.

Basal Cell Carcinoma

The second-most common kind of lip cancer is basal cell carcinoma. Basal cell carcinoma is a type of skin cancer that develops on areas exposed to the sun and is caused by ultraviolet radiation (UV) exposure. The cancer rarely spreads, but it can be locally aggressive.

Minor Salivary Gland Cancer

The lips contain minor salivary glands, and, less commonly, tumors can arise from these glands, most often involving the lower lip. These are rare tumors.

Melanoma

Melanoma rarely arises from the lips. Melanoma involving the lip can arise from the skin of the lip or from the mucosa of the oral cavity. Melanoma develops in melanocytes, skin cells that produce pigment. When melanoma arises from the mucous membranes of the lip, it is not considered a skin cancer, but instead is termed a mucosal melanoma. These are also rare tumors.

What causes skin cancer on the lip?

Like most cancers, lip cancer is usually the result of multiple factors. But several factors are known to increase the risk of developing lip cancer:

• UV radiation from sun exposure or tanning beds
• Tobacco use
• Heavy alcohol use (especially in combination with tobacco use)
• History of human immunodeficiency virus (HIV) or human papillomavirus (HPV) infections
• History of immunosuppressive medications (such as those used after organ transplant)

Lip Cancer Symptoms

Most lip cancers form on the outer portion of the lower lip. This may be because the outer surface of the lip is exposed to more UV radiation from the sun, which is a leading cause of skin cancer.

Signs and symptoms of lip cancer include:

• A lump or sore that doesn’t heal
• A crusty area of skin
• A pale or white patch
• Pain, tingling or numbness
• Bleeding

Lip Cancer Diagnosis

When lip cancer is suspected, a doctor will perform tests to reach a diagnosis. Those tests may include:

• Physical exam: The doctor examines the abnormal growth on the lip as well as the mouth, gums, tongue and neck. They may ask about health history and risk factors such as smoking and tobacco use.
• Biopsy: During a biopsy, the doctor removes a small amount of tissue from the lip, using an anesthetic to numb the tissues. A pathologist examines the cells under a microscope to look for signs of cancer.
• Imaging: Tests such as CT scans, magnetic resonance imaging (MRI) and ultrasound may be used to determine whether the cancerous cells have spread beyond the lip and into surrounding tissues or lymph nodes.

Lip Cancer Stages

When lip cancer is diagnosed, it is classified by stage. These stages indicate how advanced the cancer is:

• Stage 0: In this stage, cancerous cells are present on the lip but have not invaded the basement membrane. Stage 0 cancer is sometimes referred to as carcinoma in situ. It is cancer that has not invaded the deeper tissues. Untreated, it will progress to invasive cancer.
• Stage I: At this stage, cancer has not spread beyond the lip. Stage I lip cancer is usually less than 2 centimeters wide and does not invade deeper than 5 millimeters into the skin.
• Stage II: Stage II tumors are larger than 2 centimeters but smaller than 4 centimeters wide, or less than 2 centimeters wide but invade 5 to 10 millimeters deep.
• Stage III: Stage III lip cancers are one of the following: 
  • Between 2 to 4 centimeters wide and invade more than 10 millimeters into the skin
  • Larger than 4 centimeters but invade less than 10 millimeters into the skin
  • Any tumor with spread to one lymph node that is 3 centimeters or smaller, on the same side of the body as a tumor
• Stage IV: :In this stage, the cancer has spread either locally beyond the lip, or into one or more lymph nodes and to other parts of the body. Stage IV includes:
  • Tumors that are greater than 4 centimeters wide and invade more than 10 millimeters deep
  • Tumors that invade the jaw, sinus or face
  • Tumors that involve multiple lymph nodes, or a node on the opposite side of the neck
  • Tumors that have spread throughout the body to other area such as the lungs or liver

Lip Cancer Treatment

People with lip cancer are usually treated with surgery and/or radiation therapy.

Surgery

Surgery to treat lip cancer may involve:

• Local excision: Surgeons remove the cancerous cells and some of the tissue around it.
• Neck dissection: In neck dissection, surgeons remove lymph nodes in the neck where cancer has spread.
• Reconstructive surgery: For larger tumors, surgery to remove lip cancer may require reconstruction using tissue from other parts of the body to preserve form and function.

Radiation Therapy

Radiation therapy, or radiotherapy, uses beams of high-energy X-rays or charged particles to destroy cancer cells and keep them from spreading. There’s evidence that people who use tobacco respond better to radiotherapy if they quit before beginning treatment.

Immunotherapy

Immunotherapy involves newer treatments that use the person’s immune system to fight cancer. These targeted treatments may include monoclonal antibodies, checkpoint inhibitors and vaccines that help the immune system to recognize the tumor as foreign.

Increasingly, immunotherapy is offered as part of initial neoadjuvant therapy, treatment given before planned surgery. This is done as part of a clinical trial, but may permit a lesser surgery when there is a response. Lip cancers arising from the skin and melanomas have a better response to immunotherapy than lip cancers arising from the lining of the mouth/lip.

People with lip cancer will work with their doctors to discuss the best treatment options based on the stage of cancer, their overall health, and their treatment goals and preferences.

Outlook for People with Lip Cancer

Most people are diagnosed with lip cancer at early stages, when the cancer is easiest to treat. In the United States, about 90% of people diagnosed with lip cancer live at least five years.

People who have lip or oral cavity cancer may also be at greater risk of developing another head and neck cancer. They can lower their risk by taking steps such as quitting tobacco and alcohol use. They should also have regular follow-ups with their doctor to monitor for early signs of a second cancer.