The "para-nasal" sinuses, are bony cavities surrounding the nasal cavity itself. The largest of these, the "maxillary" sinuses are found in the upper jaw bones beneath the cheeks. The "ethmoids" are located between the eyes and the "frontal" above the nose and eyes in the forehead. Beneath the brain and behind the ethmoids is the "sphenoid" sinus.

Cancers can develop in any of these cavities, but the most common culprit is the maxillary sinus. The sinuses contain several cell types, each of which can lead to a different type of tumor.

• Squamous cell carcinoma (the most common)
• Adenocarcinoma (from gland cells)
• Melanoma (from pigment cells)
• Lymphoma (from lymph tissue)
• Sarcoma (from muscle, connective tissue or bone)

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

Risk factors for sinus (and nasal) cancers include use of tobacco and heavy consumption of alcohol. Cigarettes, cigars, pipes, chewing tobacco and snuff are all implicated.

Other risk factors include:

• Human papilloma virus (HPV) exposure
• Occupational exposure to inhalants
  • Dust from woods and textiles
  • Nickel dust
  • chromium dust
  • asbestos
  • alcohol fumes
  • glue fumes
  • solvents used in furniture and shoe production

Symptoms are varied, and may include:

• persistent nasal congestion and stuffiness
• frequent pain in the sinus regions
• pain or swelling of face, eyes or ears
• bulging of eyes
• pain or numbness in teeth
• lump on face, in nose or mouth
• frequent nose bleeds
• difficulty opening mouth

The diagnostic process begins with a thorough physical exam. Signs of nasal cavity and paranasal sinus cancer are often undistinguishable from chronic or allergic sinusitis and there are no blood or urine tests that will reveal it. Palpation of the face and neck for any anatomical distortions or masses is particularly important. General oral and nasal exam is supplemented by endoscopy, which allows the surgeon to see into the nose and throat and examine the sinus openings into the nasal cavity. Tissues can be biopsied, and indeed, sinus cancer is sometimes diagnosed during surgery for chronic sinusitis.

Once the diagnosis is suspected or confirmed by biopsy, the doctor will want to do one or more imaging studies to evaluate the extent of local disease and the possibility of distant spread. Such tests might include CT scan, MRI scan, bone scan or PET scan.

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.
Tis: carcinoma (cancer) in situ. This is a very early cancer where cancer cells are found only in a superficial tissue layer.

Tumors are thereafter divided by location-

Maxillary Sinus

T1: tumor that is limited to the inside of the sinus and does not erode or invade bone.
T2: a tumor that erodes or invades surrounding bone.
T3: tumor invades the surrounding bone, the skin of the cheek, or other sinuses.
T4a: tumor invades the bone surrounding the eye, the skin of the cheek, or the bones in the back of the throat.
T4b: tumor invades any of: the back of the eye, the brain area, or bones of the skull other than behind the nose or the back of the head.

Nasal Cavity and Ethmoid Sinus

T1: tumor that is limited to the inside of the sinus and does not erode or invade bone.
T2: a tumor that extends to the nasal cavity.
T3: tumor that extends to the maxillary sinus or to the bone surrounding the eye.
T4a: tumor that has spread throughout the facial bones or into the base of the skull.
T4b: tumor invades any of: the back of the eye, the brain area, or the back of the head.

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 0: a very early cancer (Tis), with no spread to lymph nodes (N0), or distant metastasis (M0).

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

Stage II: an invasive tumor (T2), with no spread to lymph nodes (N0), or distant metastasis (M0).

Stage III: an invasive cancer (T3), with no spread to regional lymph nodes (N0) or metastasis (M0), or an invasive cancer (T1, T2, T3) that has spread to regional lymph nodes (N1), but with 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, any tumor (T) with more significant nodal involvement (N1), but no metastasis (M0).

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

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

Besides staging a tumor, doctors also assess what is called its "grade." Because normal tissues are made up of many different types of cells grouped together, (something called "differentiation"), tumors are examined microscopically to see if their cells show relatively more or less differentiation. Tumors with less differentiation are more aggressive.

GX: the grade cannot be determined
G1: the cells look more like normal tissue (well differentiated).
G2: the cells are moderately differentiated.
G3: the cells don't look like normal tissue at all (poorly differentiated).

Treatment

Surgery and radiation therapy are the main treatments for primary sinus 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. In some cases, a person may need more than one operation to remove the cancer and to help restore the appearance and function of the tissues. A craniofacial resection or skull base surgery may be necessary in paranasal sinus cancer and will require the close cooperation of a neurosurgeon with the head and neck surgeon

Although reconstructive surgery performed by the plastic surgeon may be required after some sinus cancer resections, more often, the prosthetic dentist will create prostheses to replace the palate and upper jaw to restore function. If involvement of the neck lymph nodes is suspected, the head and neck surgeon will remove these with radical neck dissection.

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.