Most salivary cancers develop in either the parotid or submandibular glands. However, it is possible for cancers to develop in the sublingual gland or in minor salivary glands within the mouth. Most of the tumors that grow in the parotid are benign, as are about half of those appearing in the submandibular gland. Although the tumors arising in the sublinguals are few, they are virtually all malignant.

Among the theoretical risks for salivary cancers are:

• Radiation exposure
• Pesticides
• Exposure to leather industry chemicals
• Exposure to sawdust, nickel dust and silica dust
• Exposure to hair dye or hairspray

 For the discussion below, you may wish to refer to Learning - The Salivary Glands.

Symptoms are varied, and may include:

• A painless lump on the face or neck or in the mouth
• Numbness in the face
• Progressive facial paralysis
• Pain in the face, chin or jawbone
• Swollen glands in the neck

The diagnostic process begins with a thorough physical exam. Palpation of the face and neck for any anatomical distortions or masses is particularly important. When a salivary mass is found, the doctor will need to obtain a fine needle aspiration biopsy to check the cytology (cell type) of the mass. Incision biopsy (cutting into the mass to get some tissue) is nearly always avoided.If there is facial paralysis, the head and neck surgeon will also examine the mouth, throat and larynx (by endoscopy).

Doctors will also want to do one or more imaging studies to evaluate the extent of local disease and the possibility of distant spread. Such test might include CT scan, MRI scan, ultrasound or PET scan. There are as yet no "tumor marker" blood tests for salivary gland cancers.

Staging

TNM is an abbreviation for tumor (T), node (N), and metastasis (M). Doctors look at these three factors to determine the stage of cancer.

T0: no evidence of a tumor.
T1: a tumor is 2 cm or less.
T2: a tumor is at least 2 cm but not more than 4 cm.
T3: a tumor that is larger than 4 cm, but not larger than 6 cm that has spread beyond the salivary glands, but does not affect the "facial nerve" that controls facial movement.
T4a: a tumor invades the skin, jawbone, ear canal, or facial nerve.
T4b: The tumor invades the skull base or the nearby bones or encases the neck arteries.

The "N" in the TNM system stands for lymph nodes, the small, bean-shaped organs that help fight infection.

N0: no evidence of cancer in the lymph nodes.
N1: tumor has spread to a single node on the same side as the tumor and the cancer in the node is 3 cm or smaller.
N2a: tumor has spread to a single lymph node on the same side as the tumor, is larger than 3 cm but not larger than 6 cm.
N2b: tumor has spread to more than one lymph node on the same side, but none measure larger than 6 cm.
N2c: tumor has spread to more than one lymph node on either side, but none measure larger than 6 cm.
N3: tumor found in lymph nodes is larger than 6 cm.

The "M" in the TNM system describes cancer that has spread to other parts of the body.

MX: distant metastasis cannot be evaluated.
M0: cancer has not spread to other parts of the body.
M1: cancer has spread to other parts of the body.

Stages using TNM

Stage I: a noninvasive tumor (T1, T2), with no spread to lymph nodes (N0), and no distant metastasis (M0).

Stage II: an invasive tumor (T3), with no spread to lymph nodes (N0), or distant metastasis (M0).

Stage III: a smaller tumor (T1, T2) that has spread to regional lymph nodes (N1), but has no sign of metastasis (M0).

Stage IVA: any invasive tumor (T4a), with either no lymph node involvement (N0) or spread to only a single same-sided lymph node (N1), but no metastasis (M0). Or, a T3 tumor with one-sided nodal involvement (N1), but no metastasis (M0), or any tumor (T) with extensive nodal involvement (N2).

Stage IVB: any cancer (T), with more extensive spread to lymph nodes (N2, N3), and no metastasis (M0).

Stage IVC: any cancer with distant metastasis (M1).

Treatment

Surgery and radiation therapy are the stalwart treatment modalities in salivary cancer. Patients with advanced disease may be prescribed system chemotherapy.

Surgery is often a tricky enterprise because of the tumor's proximity to important nerves, the eyes and brain. Because it is the goal of surgery to remove all disease, leaving normal tissue at the margins, reconstruction of tissues or nerves may be necessary at times. When the tumor originates in the parotid, parotidectomy is performed. If the facial nerve is involved with tumor, some portion of it may need to be sacrificed and the nerve gap potentially bridged with nerve grafts. While some facial movement may be restored with such grafting, facial expressions may often be permanently affected.

If a patient cannot undergo surgery, radiation therapy may be used as primary treatment. More often, however, radiation is used in combination with surgery, either before or after the operation. Both external beam radiation (xrays focused on the tumor from an external machine), and interstitial radiation (use of implanted radioactive seeds), may be used.

It is important that the head and neck cancer patient who needs radiation be prepared by an oncologic dentist.
(See Dentistry in Head and Neck Cancer)

Chemotherapy is rarely used as a primary therapy for salivary cancer. It is more often used (within experimental protocols) in conjunction with radiation for advanced disease.