Pet Scan and Tongue Cancer

One of the most important uses of Positron Emission Tomography (PET) technology is its use in diagnosing and treating tongue cancer and other forms of oral cancer. Oral cancer is a form of cancer whose incidence rate and death rate has been decreasing slowly over the last twenty years. Although oral cancer makes up approximately 3% of all cancer cases, the American Cancer Society estimates that 28,260 new cases of oral cancer will be diagnosed in 2004. Additionally, the American Cancer Society estimates that oral cancer deaths will reach a total of approximately 7,230 cases in 2004.

About Tongue Cancer

Tongue Cancer is a form of oral cancer, a type of cancer that the American Cancer Society predicts will have 28,260 new cases in 2004. Oral cancer occurs when cells in the mouth become abnormal and cell formation occurs in an uncontrolled manner. A tumor, which is a mass of tissue, develops out of these extra cells and can either be benign (non-cancerous) or malignant (cancerous). Although, oral cancer can be classified in a variety of ways, this disease can be classified in two groups:

• Oral cavity cancer: cancer cells that develop in the oral cavity, an area that begins at the skin edge of the lips and also includes the lips, the buccal mucosa (the inside lining of the lips and cheeks), the teeth, the gums, the floor of the mouth below the tongue, the front two-thirds of the tongue, the hard palate (the bony roof of the mouth), and the retromlar trigone (the area that is behind the wisdom teeth).
• Oropharyngeal cancer: cancers cells that develop in the orophayrnx, which is the part of the throat behind the mouth. This area includes the back third of the tongue (the base of the tongue), the soft palate, the tonsillar area (the tonsils and tonsillar pillars), and the posterior pharyngeal wall (back wall of the throat).

Out of these two classes of oral cancer, over 90% of all oral cancers affecting both the oral cavity and oropharyngeal regions can be classified as squamous cell carcinoma. Squamous cell cancer develops in the squamous cells, which are flat, scale-like cells that form the lining of the oral cavity and oropharynx.

Regardless of the type of oral cancer, it is still unknown what causes oral cancer development. Recent studies have shown that tobacco usage may be the leading cause of oral cavity and orapharyngeal cancer development. Approximately 90% of all oral cancer patients use tobacco and it is believed that smokers are 6 times more likely to develop oral cancer than nonsmokers. Carcinogens, chemical-causing substances, are present in high concentration in tobacco products and are also a leading cause of cancer in the larynx, lungs, esophagus, kidneys, bladder, and several other organs.

Other identified risk factors that have been associated with an increased susceptibility to oral cancer development are:

• Alcohol: Studies have shown that heavy alcohol intake increases an individual’s susceptibility to developing an oral cancer. However, if heavy alcohol drinking is combined with smoking, the chances of oral cancer development increase exponentially.
• Ultraviolet light: Studies have shown that over 30% of patients that have cancer of the lip work in an outdoor environment associated with prolonged exposure to sunlight.
• Poor Nutrition: Dietary intakes that are low in fruits and vegetables are associated with an increased susceptibility in oral cancer development.
• Immune system suppression: Recent studies have shown that there is a correlation between oral cancer development and the consumption of immunosuppressive drugs that are used to treat certain immune system diseases or to prevent transplant organ rejection.
• Age: Individuals that are 35 years or older are at an increased risk of developing oral cavity and/or oropharyngeal cancer.

Symptoms of Tongue Cancer

Tongue cancer, a form of oral cancer, contains a number of symptoms that can lead to early detection. In most instances, a dentist will be the health care practitioner that will check a patient’s symptoms that can indicate a form of oral cancer. Although many of the symptoms of oral cancer may not necessarily indicate the development of either an oral cavity cancer or an oropharyngeal cancer, it is highly recommended that a physician be consulted if the following symptoms are exhibited:

• The presence of a sore in the mouth that does not heal within two weeks
• The presence of a constant pain in the mouth that does not go away
• A persistent lump or thickening in the cheek
• The presence of a persistent white or red patch on the gums, tongue, tonsil, or lining of the mouth
• The feeling that something is caught in the throat or a persistent sore throat that does not go away
• Difficult when chewing or swallowing
• Difficulty when moving the jaw or tongue
• The feeling of numbness in the mouth, particularly in the tongue
• The swelling of the jaw, which causes dentures to fit in an uncomfortable or poor manner
• Voice changes
• The presence of a lump or mass in the neck
• Weight loss
• Persistent bad breath

Cases of tongue cancer and other forms of oral cancer are detected through, first, an oral screening and following that a form of biopsy. A biopsy involves the taking of a sample of tissue or cells to confirm the presence of cancer. The most popular form of biopsy is an incisional biopsy, which involves the surgical removal of small tissue instrument with special instruments. Although imaging tests are effective in diagnosing the presence of cancer, it is rarely used for oral cancer diagnosis. However, imaging tests are vital in the oral cancer staging phase. Staging commences following oral cancer diagnosis and is used to determine if or how much the oral cancer has spread. The staging component of oral cancer treatment is critical as it provides the necessary information for physicians in determining an appropriate medical course of tongue cancer treatment and other forms of oral cancer treatment.

The American Cancer Society estimates that 15% of newly diagnosed oral cavity cancer and oropharynx cancer patients will have another cancer in nearby areas such as the larynx (voice box), esophagus (the digestive system area between the throat and stomach), or the lung. Additionally, the American Cancer Society estimates that between 10% and 40% of these newly diagnosed oral cancer patients will develop cancer in these same organs or develop a second case of oral cancer at a later time. For this reason, staging is a vital component of oral cancer treatment as it will determine the extent of cancer spread and possibly detect this cancer spread during its early phase where survival rates are at its highest.

There are a variety of imaging tests that are available for physicians to determine the stage of oral cancer spread. Although imaging tests such as chest x-rays, computed tomography (CT), magnetic resonance imaging (MRI), and barium swallow are often used to determine oral cancer spread, it is recommended that a Positron Emission Tomography procedure be used instead. While these imaging tests are effective in determining oral cancer spread, they are limited in their capacity as they are only able to detect increased mass sizes, which is often emblematic of a tumor presence. Consequently, these anatomical imaging tests are able to detect the presence of tumors but are unable to distinguish between a benign (non-cancerous) tumor and a malignant (cancerous) tumor.

In the staging process, PET scans are the most effective imaging tool in determining the spread of cancerous cells. As oral cancer often spreads into the larynx, esophagus, and the lung, but can spread to other areas of the body, staging is an important component of oral cancer treatment. Through PET imaging, a physician is able to determine whether or not cancerous cells have spread from the oral cavity or the oropharyngeal to other parts of the body.

Positron Emission Tomography involves the administration of a radioactive tracer that combines a radioisotope, a radioactive compound that is detected by a PET scanner, with a natural body compound, which the body is able to integrate into its system without any negative effects. In oral cancer screening, the radioactive tracer used is Fluorodeoxyglucose (FDG) that combines the natural body compound glucose with the radioisotope Fluorine-18. Although many patients have concerns about the radioactive component contained in PET imaging, Fluorine-18 contains a short half-life and disappears from the body within hours. Consequently, the PET procedure is a safe one for patients.

However, PET determines cancer spread more comprehensively than these other imaging tools, as it detects biochemistry changes among these organs and tissues. By tracing the spread of FDG in a patient’s body, PET imaging is able to establish patterns of cancer spread based on the body’s chemical reactions to FDG. As it is similar in structure to glucose, PET determines cancer spread by studying the absorption of FDG by the patient’s organs and tissues. FDG is absorbed at a faster rate by cancerous organs and tissues than healthy organs and tissues. By studying the biochemical reaction of the patient’s body, PET scan is able to produce the most accurate analysis of whether oral cancer has spread to other areas of the body.

This information is critical in determining an accurate outlook of patient recovery. For example, through a PET scan, a physician is able to view whether cancerous cells have spread to lymph nodes or other organs. If this is not the case and surgery has been undertaken, the five-year survival rate of this surgery is between 60% and 100% depending on the specifics of the oral cancer. In cases where PET imaging has shown that cancerous tumors are located in an appropriate location within the oral cavity or the oropharyngeal, surgery is often the best option. Surgery can cure oral cancer but its use depends on such variables as its location in the oral cavity or the oropharyngeal and also its size. Other medical treatments to lung cancer include: radiation therapy, which is a high energy X-ray that kills cancer cells; and chemotherapy, which uses drugs to effectively treat lung cancer.

The medical course of action used to treat oral cancer is often determined by staging. Staging is a vital step in the patient’s road to health recovery, as all of these treatment options are contingent on the size of the cancerous tumor, the spread of cancerous cells, and the location of the cancerous tumor. A PET scan is the most effective oral cancer staging tool and is a vital tool used by physicians in providing a specialized, medical plan to eradicate lung cancer from the patient.

Another valuable function of Positron Emission Tomography in tongue cancer and other forms of oral cancer treatment is its role in studying the patient’s recovery. Following staging, a physician will recommend a medical course of action that they feel are the most appropriate and effective. In most instances, chemotherapy, radiation therapy, or a combination of both is used to treat oral cancer. Although these treatments are usually effective, an important component of oral cancer treatment is determining whether active cancer cells have remained in the body following treatment.

Prior to the clinical use of PET scan, physicians applied radiation therapy and chemotherapy according to standard rules. However, with PET imaging, it is now possible for physicians to specifically cater oral cancer treatment to your particular situation. This is because Positron Emission Tomography allows a physician to view the location, extent, and resilience of a patient’s lung cancer.

Additionally, PET imaging is the most effective diagnostic tool in detecting oral tumor response to therapy. PET scans study the chemical function of the oral cavity and/or the oropharyngeal as well as other organs and tissues, and is able to produce images that show visual biochemical changes in the body caused by oral cancer. The American Cancer Society estimates that approximately 10% to 40% of newly diagnosed oral cancer patients are at risk for future recurrence. Consequently, follow-up treatments charting the possible presence of cancerous tumors are essential in fully treating oral cancer.

Unlike such anatomic imaging tools as x-rays, computed tomagraphy (CT), and magnetic resonance imaging (MRI) that detail changes in body structure such as the presence of tumors, PET imaging is able to determine whether a tumor is benign (alive tissue and non-cancerous) or malignant (dead tissue and cancerous). PET scans involve the administration of the radioactive tracer, Fluorodeoxyglucose (FDG) that combines the natural body compound glucose with the radioisotope Fluorine-18. FDG safely travels through the body where a PET scanner monitors its movement within the body. A radioactive tracer that disappears from the body within hours, FDG is able to detect cancer recurrence in successfully treated lesions as well as determine whether tumors identified in an anatomic imaging scan are cancerous or not.

This is because FDG is similar in structure to glucose, which cancerous cells absorb at a faster rate than healthy cells. By tracing the absorption rates of FDG by the targeted cells, a physician is able to determine whether successfully treated lesions are showing signs of cancer recurrence. Additionally, PET imaging is able to detect cancer recurrence in lymph nodes and/or scar tissue from surgery from surgery or another lesion sooner than an anatomical imaging procedure. PET scans are also able to distinguish between cancerous and non-cancerous tumors that are detected by anatomical imaging and are still present despite oral cancer treatment.