Introduction:
Papillomaviruses is a group of more than 200 viruses, some of which can be transmitted by sexual contact. HPV was proved to be involved in the pathogenesis of throat cancer in men and women; also, they are responsible for cervical cancer in women. Some members of the HPV family can cause respiratory tract diseases (HPV 6 and HPV 11).
Pathology
When HPV gets into the infected human cell, it combines with its nuclear DNA. After a series of biochemical interactions inside the cell nucleus, two types of proteins are formed, which are called E6 and E7. These two proteins block the cell death process, leading to unrestricted cell growth known as cancer.
Investigations
The most specific and the most sensitive test to diagnose HPV infection is PCR (polymerase chain reaction). This test depends on the messenger RNA (mRNA) inside the nucleus of the infected cell. The messenger RNA is produced by the combination of HPV and the nuclear HPV.
The second method to diagnose HPV infection is immunohistochemistry, which depends on the proteins E6 and E7 that are produced by the messenger RNA. This method is sensitive but not specific. It means that if the test is positive, the patient has cancer, but the cause might not be HPV infection.
A tissue biopsy is an effective way to detect the presence of HPV in the throat tissue. In case of the appearance of an oral wart or any oral polyp in a patient with a history of multiple sexual relations, especially oral sex activity, a biopsy must be taken for histological examination. It was found that in the case of HPV-positive tonsil cancer, the virus is present deep in the tonsil tissue. In contrast, the superficial layers of the tonsil are completely free from the virus. So, it is better to surgically remove the whole tonsil to be examined, not only a superficial biopsy.
Types:
As we have read before, human papillomavirus has many types. About 60 % of these are cutaneous, which do not produce cancer. At the same time, 40 % of these are mucosal, which are divided into low-risk groups and high-risk groups. The low-risk group, HPV 6 and 11, produce pulmonary papillomatosis and genital warts. The high-risk group, types 16 and 18, produce cervical, anogenital, and oropharyngeal cancers.
Risk Factors
Human papillomavirus are transmitted in several ways, like multiple sexual partners and open mouth deep kissing, but the most effective way is oral sex. Oropharyngeal cancer related to HPV occurs with chronic HPV infection.
Oropharyngeal Cancer:
Oropharyngeal cancers are divided into:
1) HPV-Negative Oropharyngeal Cancer:
An example of the HPV-negative type is cancer caused by excessive consumption of cigarettes and alcohol. The lesion of HPV-negative type commonly presents as a pharyngeal firm ulcer surrounded by an area of mucosal changes, as cigarette smoke and alcohol affect not only the area of the ulcer but the entire mouth mucosa and the tongue. This type is most commonly seen in the age above 60 years with a long history of cigarette smoking and alcohol consumption.
2) HPV-Positive Oropharyngeal Cancer:
In the HPV-positive type, the lesion looks more focal, well-defined, and with normal tissue around it. This type is most commonly seen in adults below 60 years with a history of repeated HPV infection and bad sexual habits. Other symptoms can be found as enlargement of tonsils, pain while swallowing, and neck masses. Sometimes, the only symptom can be just a foreign body sensation in the throat. HPV-positive oropharyngeal cancer is more common in males than in females.
Management of HPV-Positive Oropharyngeal Cancer
It was approved that HPV-positive oropharyngeal cancer treatment outcomes are much better than that of HPV-negative oropharyngeal cancer because the HPV-positive type is present in young patients who do not have a history of cigarette smoking and alcohol. Treatment modalities of HPV-positive oropharyngeal cancer are classified into surgical and nonsurgical modalities.
1) Surgical Methods - The classical surgery for HPV-positive cancer is an open surgery, which takes 13 hours, followed by at least two weeks of postsurgical under observation and close follow-up of the patient at the hospital. After introducing robotic surgery, the time of the oropharyngeal cancer surgery is decreased to just 2 hours, followed by a few hours to few days of postsurgical follow-up.
2) Nonsurgical Methods - Radiotherapy and intravenous chemotherapy are done. Radiotherapy has some disadvantages, like burns that affect the whole neck tissues causing breathing and swallowing difficulties. Sometimes, the patient needs a tracheostomy to maintain his breathing or a nasogastric tube for nutrition.
The treatment modality is decided according to the severity of the disease, the patient's general health, and the patient's outcome expectations. Sometimes, both surgical and nonsurgical modalities are used for the same patient.
Prevention
Almost all sexually active people have been infected by HPV even if they do not know, as HPV infection is a silent infection in 90 % of the infected people. Fortunately, HPV takes from 10 to 12 years from the start of the infection to produce oropharyngeal cancer. The immune response of the infected patient plays a great role in suppressing the activity of the virus.
As HPV is a sexually transmitted virus, the most effective way to prevent HPV infection is lifetime mutual monogamy, using condoms, and decreasing sexual partners as possible. HPV vaccination has a great role in lowering the rate of HPV-positive oropharyngeal cancer. HPV vaccination gives its best protective effects when administered during the preteen years. The vaccination is introduced in the form of 3 shots. The second shot is taken from 1 to 2 months after the first one, while the third shot is taken 6 months after the first one. The whole course of the vaccination must be completed for it to be effective. Sometimes, HPV infected patients need psychological support, especially females.
Conclusion
Therefore, human papilloma virus can be treated with proper medication. However if patients still have persistent symptoms for over two years, there are higher chances of oropharyngeal cancer. Diagnosing the condition at the earliest possible, can prevent the spread of this disease. Also, it is crucial to go for frequent follow-ups to monitor the progress of the condition.
