Human papillomavirus infection is one of the sexually transmitted diseases associated with human papillomavirus (HPV).
HPV is considered a predisposing factor for cervical cancer, as well as a provoker of other cancers: penis, oropharynx, rectum. The annual global incidence of about 1, 5 million.
The overall prevalence of human papillomavirus in the general population is 10% among women and 20% among men.
HPV infection is more common in sexually active young women and men between the ages of 16 and 25.
About 50% of gay men who have anal sex are at risk for developing squamous cell carcinoma, which is preceded by anorectal warts.
For heterosexual men and women, this risk is 20%.
The most significant predictor of HPV infection in men or women is the number of sexual partners.
About 189 HPV genotypes are classified according to their biological niche and oncogenic potential. About 40 of them can affect the urogenital tract.> zxtable border = "1" cellpadding = "0" >
Women with invasive cervical cancer are more likely to be diagnosed with HPV types
16, 18, 33, 45, 31 and 58, but the clinical outcome may vary.
Vaccination against HPV infection has recently gained popularity, but experts say vaccination does not exempt from regular visits to the doctor. There is evidence that the effect weakens after 15-20 years, and it is worth considering the role of other unexplored genotypes of the virus on which the vaccine has no effect.
Methods for diagnosing HPV infection
Note that the diagnosis may be suspected by visual examination, during which the location of the lesions and the clinical manifestations of human papillomavirus infection are determined.
There are many ways to diagnose HPV:
- cytological method (PAP test);
- liquid cytology;
- advanced colposcopy;
- PCR (polymerase chain reaction, confirms the presence of human papillomavirus DNA);
- determination of viral load (HPV-Digene test), real-time PCR - methods for detecting the number of copies of DNA-oncogenic viruses;
- morphological studies;
- tumor markers with determination of oncoproteins p16, ki67, mcm2, mcm7, etc.
PCR diagnosis of HPV
PCR diagnostics can be qualitative and quantitative (real-time PCR, HPV-Digene test).
Cervical cancer screening and early detection of infection are currently recognized as the most effective measures to control cervical cancer.
Previously used screenings in women are cytological and histological, but due to their low specificity, re-examination is required after a short period of time. PCR diagnosis with a negative result may reduce the frequency of gynecological examinations (1 time / 5-6 years).
It should be noted that the qualitative definition of HPV is not very informative, as it allows only confirmation of the infection, therefore, to address the need for therapy in both men and women with clinical manifestations, it is betterto perform an HPV-Digene test that will reveal the concentration of the virus.
The polymerase chain reaction uses type and type-specific primers that quantify the risk of malignancy (malignancy). Determining the viral load is the main goal of these tests.
If the level of HPV DNA is higher than 5, 000 genomes - the probability of developing cancer is high, therapy aimed at suppressing HPV activity is indicated. Less than 3, 000 genomes - low risk.
PCR diagnosis can detect all oncogenic types of viruses in men and women.
In addition to testing for HPV, it is mandatory to diagnose sexually transmitted diseases, HIV, these diseases are considered cofactors of human papillomavirus infection.
Because the link between HPV and cancer of the cervix, penis and rectal cancer has been proven, molecular methods for detecting HPV DNA in biomaterial are justified. Use the following:
- vaginal discharge and exudate from the cervix in women;
- scraping the urethra in men;
- anal flow;
- pharyngeal mucus;
Italian scientists conducted a study that showed that PCR diagnosis (88-100%) is more effective than cytology (34-86%) for the prevention of invasive cervical cancer.
The specificity of the HPV test (82-97%) is considered higher than the specificity of cytology (78-99%).
In most people, human papillomavirus infection goes away on its own without medication. But in women over the age of 30, HPV is rarely eliminated spontaneously, so in the context of cancer vigilance, a regular check-up is recommended, which in the Russian Federation, according to current orders, is performed once a year.
In some foreign countries, if the result of PCR analysis for papillomavirus and cytology in a woman is negative, the interval for passing the test is 1 time in 3 years, in the case of negative cytology, but positive results of polymerase chain reaction for HPV fromHighly oncogenic types are performed annually by colposcopy.
Men are examined annually by a urologist, with formations suspected of papillomavirus infection, consultation with a dermatovenerologist is justified.
According to the indications, especially if there is a suspicion of degeneration in a malignant tumor, it is possible to make a biopsy.
Colposcopy in women
Colposcopy is the most accessible diagnostic method for women, the results of which allow to draw conclusions about the need to continue examinations.
Studies show that 99-100% of cervical cancers are associated with highly oncogenic types of human papillomavirus.
During advanced colposcopy, the cervix is treated with a solution or acetic acid, which interacts with the following:
- epithelial whitening;
- atypical zone of transformation.
After staining with the solution, the modified area on the background of HPV takes the form of "semolina".
In cytological examination, the leading signs of infection are the presence of cells with koilocytosis and dyskeratosis, which is evidence in favor of CIN.
Cytological diagnosis of HPV
The material is taken with a special brush. In women - scraping from a suspicious area of the cervix, in men - from the urethra, determine the type, number and change of cells of the mucosa.
Pap smear, Pap test and liquid cytology
Pap smear - a non-invasive test used in gynecological practice, allows you to diagnose cancer of the cervix and endometrium in the early stages, before the development of clinical manifestations. The aim is to detect atypical cells suspected of a tumor process. In the standard Pap test, the cytobrush material is stained and examined under a microscope.
A screening study for cancer was developed in 1940 by G. Papanikolaou, examining exfoliated cells that are suspected of cancer or precancerous lesions.
Liquid cytology is a type of Pap test, a more modern and effective method for diagnosing HPV. When conducting research, the biomaterial is placed not on a glass slide, but in a special liquid preservative.
Targeted biopsy of the cervix and curettage of the lining of the cervical canal with subsequent histological examination are performed when:
- detection of atypical cells based on cytology results,
- with highly oncogenic HPV types with changes identified by colposcopy,
- with obvious signs of pathology, without taking into account the results of HPV tests.
In men, it is possible to do a biopsy in case of neoplasms with suspected HPV. If warts are located deep in the urethra, biopsy material is taken during urethroscopy.
Histology for HPV is a diagnostic method in which specially treated papilloma tissue is examined under a microscope. The study is 100% informative for the confirmation of malignancy.
- exophytic flat warts with dyskeratosis and acanthosis,
- changes in the cytoplasm of the squamous epithelium,
- cervical cancer,
- penis cancer
- anorectal cancer.
Several options have been proposed for controlling human papillomavirus infection. In the first case cytological examination is used, in the second, with the help of PCR diagnostics, it is determined whether HPV is transient. Therefore, PCR analysis is prescribed again after 6 months.
Who should be tested for HPV
Qualitative tests are more often used for mass examinations for prevention, quantitative tests are prescribed when the clinical picture is suspicious for HPV infection.
In addition, the indications for HPV testing are as follows:
- unprotected "accidental" sexual intercourse;
- monitoring the effectiveness of therapy;
- detection of STIs;
- burdened gynecological history;
- HIV infection;
- planned pregnancy;
- has more than one sexual partner.
Women of childbearing potential are recommended to be tested for HPV once every 3-5 years.
What diagnosis is needed - the doctor will tell you.
Examination of men for HPV is justified only in clinical manifestations, sometimes the diagnosis is made with a busy obstetric and gynecological history of the partner.