Pharyngeal cancer is an malignant tumor of the pharynx, usually develops from degenerated mucosal cells. With a share of 5 percent of all cancer cases, pharyngeal cancer is a relatively common tumor. The main risk factors for developing pharyngeal cancer are smoking, alcohol consumption, and human papilloma viruses. The age of onset for pharyngeal cancer is usually between 50 to 70 years.
Incidence of throat cancer
Pharyngeal cancer is associated with accounts for 5 percent of all cancers a relatively common tumor. The entire pharynx can be further subdivided into tonsils, palate and the base of the tongue. According to the exact location of the tumor, it is then z.B. known as tonsillar cancer (tonsillar carcinoma), nasopharyngeal cancer (nasopharyngeal carcinoma), oral cavity cancer (oropharyngeal carcinoma) or pharyngeal cancer (hypopharyngeal carcinoma).
Origin of pharyngeal cancer
The pharyngeal cancer develops mostly from degenerated mucosal cells. Under the microscope, these mucosal cells look like plates lying on top of each other, so the mucosa is also called squamous epithelium. If such a cell degenerates into cancer, it is then called a Squamous cell carcinoma. This is manifested in the patient by a swelling of the affected organ and often also by an irregular appearance of the tissue.
Tobacco and alcohol consumption as risk factors for throat cancer
Various risk factors can lead to a degeneration of the mucous membrane cells and to pharyngeal cancer. The most common risk factor for throat cancer is the regular consumption of tobacco smoke and the excessive consumption of alcohol. In cigarette smoke, for example, more than a hundred different carcinogenic substances can be detected. Will Alcohol and tobacco consumed at the same time, the risk of degeneration is multiplied even more. However, it takes a relatively long time for the regularly consumed toxins A pharyngeal cancer actually develops. The age of onset of pharyngeal cancer is usually between 50 to 70 years of age.
Human papilloma virus (HPV) as a trigger of pharyngeal cancer
In recent years, it has been found that throat cancer can also be caused by a specific virus. This virus is known as the human papillomavirus (HPV). There are more than a hundred different types of the HP virus. Most of these viruses are harmless and cause z.B. merely skin warts. However, certain forms of the virus are capable of nesting in the mucosal cells of the throat and causing throat cancer there. These include HPV 16 and HPV 18. Incidentally, these are the same viruses that can trigger cervical cancer in women. If the HP virus is responsible for the development of pharyngeal cancer, the tumor has very specific characteristics. It responds better to radiation and chemotherapy, and affected patients have Better chances of survival, since the tumor less aggressive is.
Symptoms of pharyngeal cancer
Pharyngeal cancer often initially manifests itself with Sore Throat noticeable. This can be caused by throat radiate into the ear and are therefore occasionally misinterpreted as ear disease. Because there are a large number of lymphatic pathways in the throat, there are often Settlement of the tumor in the cervical lymph nodes. Surprisingly, it can happen that these metastases grow much faster than the actual pharyngeal cancer. Why this is so has not yet been conclusively explained scientifically. In any case, however, it can happen that a Nodes on the neck the first symptom of pharyngeal cancer is. Sometimes the actual tumor in the throat has grown so small or hidden that you can not see it with the naked eye. The tonsils in particular are crisscrossed by deep furrows, and the tumor can grow invisibly in these furrows for a long time.
Figure 1: It is a cancerous tumor of the tongue. What is noticeable here is a clear asymmetry of the tongue with a considerable, unilateral swelling of the tongue. The patient presented to the clinic due to severe pain.
Diagnosis of pharyngeal cancer
If an ENT specialist has examined the tumor through the Mirror examination If the tumor is discovered by an ENT specialist, it must first be tissue sampling take place. Only with this microscopic examination it is possible to make an exact diagnosis. Normally the removal is done under general anesthesia. This has the advantage that the entire upper respiratory and airways can be examined at the same time, since in 10 to 20 percent of all cases of pharyngeal cancer other tumors are found at the same time. This special mirror examination is called Panendoscopy denotes. In order to determine the extent of the pharyngeal cancer and to detect possible metastases to other parts of the body, a so-called Computed tomography is performed. Alternatively, it is also possible to MRI The tumor can even be visualized in a more informative way in special cases.
Once the diagnosis and the extent of the pharyngeal cancer are known and the patient has been examined for metastases to other parts of the body, it must be discussed individually which form of therapy should be considered.
Figure 2: The MRI shows a tumor in the region of the tongue, which is clearly distinguishable from healthy tissue due to its dark coloration (s. arrow). With the help of magnetic resonance imaging, tumors of the tongue can often be well depicted.
Treatment of throat cancer
For the treatment of pharyngeal cancer several forms of therapy available. If a cure of the pharyngeal cancer is possible, it is called a curative therapy. For this two procedures possible, namely the operation and radiation. Surgical therapy is used if it is technically possible to remove the tumor completely by surgery. In addition, it should be ensured before surgery that no distant metastases (for example, lung metastases) are present.
Surgical therapy
Today, the primary tumor can be identified in many cases gently remove the tumor with the laser. For this purpose, under general anesthesia, the laser beam is used like a scalpel through the open mouth and the tumor is removed with a safety margin. An advantage of the laser is that it obliterates the blood vessels around the tumor due to the heat generated, thus enabling a procedure with little bleeding. Due to the frequent metastasis of the tumor to the cervical lymph nodes, the cervical lymph nodes surgically removed at the same time. This procedure is called "neck dissection. This requires an incision from the outside of the neck.
In the case of larger tumors, it is occasionally necessary to fill in the tissue defect created by the tumor removal. Here, the surgeon often uses a graft from the patient’s forearm, called the. Radialis flap, which grows by microscopic connection of artery and vein of the neck in the mouth area.
Figure 3: The figure shows a patient with a large neck lymph node metastasis. The picture was taken shortly before the operation. Despite the size of the tumor, the metastasis could be surgically removed without complications. Due to the advanced stage of the tumor, the patient had to undergo additional radiation after surgery. Today, 6 years after the treatment, he is considered cured and has fortunately completed the treatment without serious side effects.
Radiation of pharyngeal cancer
A Radiation alone without surgery can be done for pharyngeal cancer also effectively and lead to a cure. The advantage of irradiation is that no surgery needs to be performed. Therefore, radiotherapy alone is often used in cases where the Patient not healthy enough for general anesthesia and the long operation, for example, if other serious illnesses such as heart disease are present. Radiation alone is also given if the throat cancer cannot be completely removed by surgery. If very large tumors are present, the tumor has often reached the spine or carotid artery and is firmly attached to them. In such cases, surgery is too risky or technically impossible, and the patient is classified as "inoperable".
In recent years, radiation has been shown to be more effective when combined with mild chemotherapy. This is then referred to as Radiochemotherapy. This combined radiochemotherapy is now standard and is only not performed if the patient cannot be given chemotherapy (z.B. liver problems). Irradiation takes place over a period of approx. 6 weeks instead of. Chemotherapy is then administered at the same time as radiotherapy.
combination of surgical therapy and radiation
In some cases, surgery and radiation are combined for pharyngeal cancer. Radiation after successful surgical removal of the tumor is useful if tumor metastases are present in the cervical lymph nodes or the pharyngeal cancer was very large. This post-radiation reduces the risk of individual tumor cells remaining in the patient. Remaining tumor cells can cause the pharyngeal cancer to start growing again after a period of time. This is called a recurrent tumor. These recurrence tumors are usually very difficult to treat.
Palliative therapy
If the pharyngeal cancer is no longer curable is present, this is referred to as a "palliative" situation. However, effective palliative therapies are also available for a palliative patient. In order to push back the pharyngeal cancer or at least to slow down the tumor growth, the so-called palliative chemotherapy used. Various drugs are available for this purpose, and the physician must decide individually which therapy should be considered. In recent years, a new form of anticancer drugs has also been used successfully: the so-called Target therapeutics. The advantage of these modern chemo drugs is that they attack the cancer cells more specifically and therefore cause the typical side effects such as hair loss and nausea less frequently.
chances of cure for pharyngeal cancer
If the throat cancer in an early stage is detected, the Prognosis good. But also patients who have already had metastases to the cervical lymph nodes can be distinguished by a combined surgical and radiation chemotherapy cured in up to 60 percent of all cases are. The chances of cure are significantly worse if Absettlement in other organs tumors such as lung, liver or bone are present. Often then no long-term cure more possible.
Fig. 4: Microscopic image of a tongue tumor. Red staining shows that the HP virus has caused the tumor. In the case of tumors not caused by HPV viruses, the so-called "HPV" is the most common form of cancer. p16 immunohistochemistry does not result in staining.
Currently very topical and intensively studied in research is the finding that between by HP virus-caused tumors and HPV-negative tumors can be distinguished. In recent years, researchers have found that patients in particular have with a tumor caused by HP viruses have better chances of recovery have. Special tests can be used to find out whether HP viruses are responsible for the development of the tumor. For this purpose, a staining of tumor samples is an option, which can be performed quickly and inexpensively with special antibodies (p16).
Medical studies are currently underway to determine which therapy is most effective for HPV-positive and negative tumors. At the moment, however, the distinction between the two tumor variants is not yet decisive for the treatment. Vaccination against HP viruses in throat cancer is also not yet established in standard therapy.