Adenoid Cystic Carcinoma

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Introduction

Cancer begins when healthy cells change and grow out of control, forming a mass called a tumor. A tumor can be cancerous or benign. A cancerous tumor is malignant, meaning it can grow and spread to other parts of the body. A benign tumor means the tumor can grow but will not spread.

Adenoid cystic carcinoma (AdCC) is a rare form of adenocarcinoma, which is a broad term describing any cancer that begins in glandular tissues. AdCC is found mainly in the head and neck, but it can occasionally occur other locations in the body, including a woman’s uterus. AdCC most commonly occurs in the salivary glands, which consist of clusters of cells that secrete saliva scattered throughout the upper aerodigestive tract. The upper aerodigestive tract includes the organs and tissues of the upper respiratory tract, such as the lips, mouth, tongue, nose, throat, vocal cords, and part of the esophagus and windpipe. A tumor may begin in the:

  • Minor salivary glands
    • Palate — roof of the mouth
    • Nasopharynx — an air passageway at the upper part of the throat and behind the nose
    • Tongue base — the back third of the tongue
    • Mucosal lining of the mouth — the inner lining of the mouth; glands located here produce mucus
    • Larynx — the voice box
    • Trachea — the windpipe
  • Major salivary glands
    • Parotid — the largest salivary gland found on either side of the face in front of each ear
    • Submandibular — found under the jawbone
    • Sublingual glands — located in the bottom of the mouth under the tongue

Regardless of where it starts, AdCC tends to spread along nerves, known as a perineural invasion, or through the bloodstream. It spreads to the lymph nodes in only about 5% to 10% of cases. The most common place of metastases, which is the spread of cancer to another part of the body, is the lung. AdCC is known for having long periods of no growth, or indolence, followed by growth spurts. However, AdCC can behave aggressively in some people, making the course of the AdCC unpredictable.  

Besides being classified based on where the cancer begins, AdCC is also described based on the histologic variations of the tumor, meaning what tumor cells look like under a microscope. The tumor can be classified as cylindroma, cribiform, or solid AdCC. AdCC is sometimes classified as a disease of the minor salivary gland, even though it may begin at other locations.

Statistics

AdCC is rare. Each year, about 1,200 people are diagnosed with AdCC in the United States and about 60% are women. AdCC is most often found in younger and middle-aged adults, but anyone of any age can be diagnosed, including children.

The 5-year survival rate tells you what percent of people live at least 5 years after the cancer is found. Percent means how many out of 100. The 5-year survival rate for people with AdCC is approximately 89%. The 15-year survival rate for people with AdCC is approximately 40%.

Tumor growth for AdCC is often slow, and people may live a long time with metastatic disease. However, a late recurrence of AdCC is common and can occur many years after initial treatment. A late recurrence is cancer that has come back after treatment.

It is important to remember that statistics on the survival rates for people with AdCC are an estimate. The estimate comes from data based on the number of people with this cancer in the United States. Also, experts measure the survival statistics every 5 years. So the estimate may not show the results of better diagnosis or treatment available for less than 5 years. Talk with your doctor if you have any questions about this information. Learn more about understanding statistics.

Risk Factors

A risk factor is anything that increases a person’s chance of developing cancer. Although risk factors often influence the development of cancer, most do not directly cause cancer. Some people with several risk factors never develop cancer, while others with no known risk factors do. Knowing your risk factors and talking about them with your doctor may help you make more informed lifestyle and health care choices.

The cause of AdCC is not known at this time, and risk factors for this type of cancer have not been proven consistently with scientific research. There is some evidence that the p53 tumor suppressor gene is somehow inactivated in advanced and aggressive forms of AdCC. The p53 gene limits cell growth by monitoring the rate at which cells divide.

Symptoms and Signs

People with AdCC may experience the following symptoms or signs. Sometimes, people with AdCC do not have any of these changes. Or, the cause of a symptom may be a different medical condition that is not cancer.

The initial symptoms of AdCC depend on the location of the tumor. Early lesions of the salivary glands may appear as painless, usually slow-growing masses underneath the normal lining of the mouth or skin of the face. Because there are many salivary glands under the mucosal lining of the mouth, throat, and sinuses, lumps in these locations could be from this type of tumor. Other symptoms may include: 

  • A lump on the palate, under the tongue, or in the bottom of the mouth
  • An abnormal area on the lining of the mouth
  • Numbness of the upper jaw, palate, face, or tongue
  • Difficulty swallowing
  • Hoarseness
  • Dull pain
  • A bump or nodule in front of the ear or underneath the jaw
  • Paralysis of a facial nerve 

If you are concerned about any changes you experience, please talk with your doctor. Your doctor will ask how long and how often you have been experiencing the symptom(s), in addition to other questions. This is to help figure out the cause of the problem, called a diagnosis.

If cancer is diagnosed, relieving symptoms remains an important part of cancer care and treatment. This may also be called symptom management, palliative care, or supportive care. Be sure to talk with your health care team about the symptoms you experience, including any new symptoms or a change in symptoms. 

Diagnosis

Doctors use many tests to find, or diagnose, cancer. They also do tests to learn if cancer has spread to another part of the body from where it started. If this happens, it is called metastasis. For example, imaging tests can show if the cancer has spread. Imaging tests show pictures of the inside of the body. Doctors may also do tests to learn which treatments could work best. 

For most types of cancer, a biopsy is the only sure way for the doctor to know whether an area of the body has cancer. In a biopsy, the doctor takes a small sample of tissue for testing in a laboratory. If a biopsy is not possible, the doctor may suggest other tests that will help make a diagnosis. 

This list describes options for diagnosing this type of cancer. Not all tests listed below will be used for every person. Your doctor may consider these factors when choosing a diagnostic test:

  • The type of cancer suspected
  • Your signs and symptoms
  • Your age and medical condition
  • The results of earlier medical tests

In addition to a physical examination, the following tests may be used to diagnose AdCC:

  • Biopsy. A biopsy is the removal of a small amount of tissue for examination under a microscope. Other tests can suggest that cancer is present, but only a biopsy can make a definite diagnosis. A pathologist then analyzes the sample(s).  A pathologist is a doctor who specializes in interpreting laboratory tests and evaluating cells, tissues, and organs to diagnose disease. The pathology of the salivary gland may be complicated, even among experienced pathologists. This is why it is important that the tissue is examined by a head and neck pathologist who is experienced in diagnosing salivary disease. The biopsy can be performed using a fine needle biopsy or by surgically removing part or all of the tumor. A fine needle biopsy is also called fine needle aspiration or FNA. This procedure uses a thin needle to remove fluid and cells from the suspicious area. An AdCC tumor is characterized by a distinctive pattern in which bundles of epithelial cells surround and/or infiltrate ducts or glandular structures within the organ. Frequently, diagnosis of AdCC is made after the surgical removal of a tumor first thought to be benign.
  • Imaging tests. Imaging techniques, primarily magnetic resonance imaging (MRI) or computed tomography (CT) scan, are useful to help doctors see the size and location of the tumor before surgery. A positron emission tomography (PET) scan may also be used to determine if the tumor has spread to other parts of the body. 
    • Magnetic resonance imaging (MRI). An MRI uses magnetic fields, not x-rays, to produce detailed images of the body. MRI can be used to measure the tumor’s size. A special dye called a contrast medium is given before the scan to create a clearer picture. This dye can be injected into a patient’s vein or given as a pill to swallow. An MRI is very useful for identifying perineural spread of AdCC. Perineural spread is growth of the tumor along nerve branches. 
    • Computed tomography (CT or CAT scan). A CT scan creates a 3-dimensional picture of the inside of the body using x-rays taken from different angles. A computer combines these images into a detailed, cross-sectional view that shows any abnormalities or tumors. A CT scan can be used to measure the tumor’s size. Sometimes, a special dye called a contrast medium is given before the scan to provide better detail on the image. This dye can be injected into a patient’s vein or given as a pill to swallow. 
    • Positron emission tomography (PET) or PET-CT scan. A PET scan is usually combined with a CT scan (see above), called a PET-CT scan. However, you may hear your doctor refer to this procedure just as a PET scan. A small amount of a radioactive sugar substance is injected into the patient’s body. This sugar substance is taken up by cells that use the most energy. Because cancer tends to use energy actively, it absorbs more of the radioactive substance. A scanner then detects this substance to produce images of the inside of the body

Stages

Staging is a way of describing where a cancerous tumor is located, if or where it has spread, and whether it is affecting other parts of the body. Doctors use diagnostic tests to find out the cancer’s stage, so staging may not be complete until all of the tests are finished. Knowing the stage helps the doctor to decide what kind of treatment plan is best and can help predict a patient’s prognosis, which is the chance of recovery. There are different stage descriptions for different types of cancer.

TNM staging system

There is no standard staging system used for AdCC, but the staging system for a major salivary gland tumor is often used, which is based on the TNM system. Doctors use the results from diagnostic tests and scans to answer these questions:

  • Tumor (T): How large is the primary tumor? Where is it located?
  • Node (N): Has the tumor spread to the lymph nodes? If so, where and how many? 
  • Metastasis (M): Has the cancer metastasized to other parts of the body? If so, where and how much? 

The results are combined to determine the stage of cancer for each person. There are five stages: stage 0 (zero) and stages I through IV (1 through 4). The stage provides a common way of describing the cancer so doctors can work together to plan the best treatments.

Here are more details on each part of the TNM system:

Tumor (T) 

Using the TNM system, the “T” plus a letter or number (0 to 4) is used to describe the size and location of the tumor. Some stages are divided into smaller groups that help describe the tumor in even more detail. Specific tumor stage information is listed below.

TX: The primary tumor cannot be evaluated.

T0 (T plus zero): No evidence of a tumor is found.

T1: The tumor is small, 2 centimeters (cm) at its widest dimension. It is also noninvasive, which means it has not grown outside the area where it began.

T2: The tumor is larger, between 2 cm and 4 cm, but noninvasive.

T3: The tumor is larger than 4 cm, but not larger than 6 cm, and has spread beyond the salivary gland. However, the tumor does not affect the seventh nerve, which is the facial nerve that controls such expressions as smiles or frowns.

T4a: The tumor has invaded the skin, jawbone, ear canal, and/or facial nerve.

T4b: The tumor has invaded the skull base and/or the nearby bones and/or encases the arteries.

Node (N) 

The “N” in the TNM staging system is for lymph nodes, the tiny, bean-shaped organs help fight infection. For AdCC, lymph nodes near the head and neck are called regional lymph nodes. Lymph nodes in other parts of the body are called distant lymph nodes.

NX: The neck has undergone an intervention that prevents the evaluation of lymph nodes.

N0: There is no evidence of cancer in the regional nodes.

N1: The cancer has spread to a single node on the same side as the primary tumor, and the cancer found in the node is 3 cm or smaller.

N2: Describes any of these conditions:

N2a: Thecancer has spread to a single lymph node on the same side as the primary tumor and is larger than 3 cm, but not larger than 6 cm.

N2b: The cancer has spread to more than one lymph node on the same side as the primary tumor, and no tumor measures larger than 6 cm.

N2c: The cancer has spread to more than one lymph node on either side of the body, and no tumor measures larger than 6 cm.

N3: The cancer found in the lymph nodes is larger than 6 cm.

Metastasis (M)

The “M” in the TNM system describes cancer that has spread to other parts of the body, called distant metastatsis.

MX: Distant metastasis cannot be evaluated.

M0: The cancer has not spread to other parts of the body.

M1: The cancer has spread to other parts of the body.

Cancer stage grouping

Doctors assign the stage of the cancer by combining the T, N, and M classifications.

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

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

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

Stage IVA: This stage describes any invasive tumor (T4a) that either has no lymph node involvement (N0) or has spread to only a single, same-sided lymph node (N1), but with no metastasis (M0). It is also used to describe a T3 tumor with one-sided nodal involvement (N1) but no metastasis (M0), or any tumor (any T) with extensive nodal involvement (N2) but no metastasis (M0).

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

Stage IVC: This stage describes any cancer (any T, any N) with distant metastasis (M1).

Recurrent: Recurrent cancer is cancer has come back after treatment. If the cancer does return, there will be another round of tests to learn about the extent of the recurrence. These tests and scans are often similar to those done at the time of the original diagnosis.

Author: pauadu

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