1. Overview of human papillomavirus infection
Human papillomavirus (HPV) infection is a common female lower genital tract infection and is a sexually transmitted infection. Direct skin-to-skin contact is the most common route of transmission. More than 100 types of HPV viruses have been identified, and more than 40 of them have been associated with reproductive tract infections. Based on their potential to cause cervical cancer, in 2012 the International Agency for Research on Cancer (IARC) classified them into high-risk, suspected high-risk and low-risk types.
The first two are associated with cervical cancer and high-grade vulvar, vaginal, and cervical squamous intraepithelial lesions (SIL), while the latter is associated with genital warts and low-grade vulvar, vaginal, and cervical SIL. Common high-risk types include: 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 12 types; suspected high-risk types include: 26, 53, 66, 67, 68, 70, 73, 82, 8 types; low-risk types include: 6, 11, 40, 42, 43, 44, 54, 61, 72, 81, 89, 11 types.
HPV infection in the lower genital tract is relatively common, and the infection rate in the general population is reported to be about 10% abroad. In China, there are discrepancies in reports on the population prevalence and distribution of high-risk HPV types, and there is a lack of multicenter studies with large samples.
The majority of HPV infections in the genital tract are transient and have no clinical symptoms; about 90% of HPV infections resolve within 2 years, and the time to resolve is mainly determined by the HPV type, with low-risk HPV taking 5-6 months and high-risk HPV taking 8-24 months; only a very small number of HPV-infected patients develop clinically visible lower Only a very small number of people with HPV infection develop clinically visible lower genital tract warts, squamous intraepithelial lesions and cancer.
2.HPV testing methods
The current clinical application of HPV detection methods are mainly for the DNA testing of the viral genome, mainly divided into HPV typing test and non-typing test. At present, there are also partial typing tests based on HPV non-typing, mainly detecting 12 high-risk types and 2 suspected high-risk types 66 and 68, of which 16 and 18 are typing tests, while the others are non-typing tests. The advantage of fractional testing is that it can identify the specific type of HPV infection and can identify multiple types of mixed infections.
Fractional testing can be used clinically to determine if HPV infection is persistent or re-infected with the same type. HPV testing without typing can identify high-risk HPV infections, but not specific types, and can be used clinically to screen for cervical SIL and cervical cancer, but not to determine persistent infection or reinfection with a particular HPV type.
Other HPV detection methods include cytological examination of dug-out cells, immunohistochemical detection of HPV antigen, and HPV antibody detection, but they are less commonly used in clinical practice due to low sensitivity and poor specificity. At present, high-risk HPV mRNA detection technology, especially the detection of E6 and E7 mRNA and the quantitative detection of HPV DNA have emerged, and their clinical significance needs further study.
3. Clinical application of HPV testing
3.1 High-risk HPV testing for cervical cancer screening
Currently, high-risk HPV testing has become one of the main methods for cervical cancer screening, and three methods are commonly used, namely combined cytology and HPV screening, cytology screening and HPV screening alone.
3.1.1 Combined HPV and cytology for cervical cancer screening
The starting age for combined screening is 30 years and the ending age is 65 years. For women aged 65 years and older, screening is discontinued if they have no history of cervical intraepithelial neoplasia (CIN)2 or higher in the past 20 years and have been adequately screened with negative results. Combined screening can be performed using both typed and untyped HPV tests. (1) Combined screening results are negative: then combined screening is performed every 5 years. (2) HPV-positive with atypical squamous cell cytology (ASC-US): direct colposcopy. (3) HPV positive and cytology negative: then rescreen at 12 months with combined screening or perform typing test for HPV 16 and 18. If HPV 16 or 18 positive, colposcopy should be performed, if HPV 16 and 18 negative, then combined screening at 12 months. (4) HPV negative with ASC-US cytology: combined screening every 3 years. In addition women with cytology of low grade squamous intraepithelial lesions (LSIL), high grade squamous intraepithelial lesions (HSIL) and squamous epithelial cell carcinoma of the cervix, regardless of HPV results, were screened directly with colposcopy.
3.1.2 The role of HPV testing in triage of ASC-US with cytologic findings of undefined diagnostic significance
Currently, cytology is still used as the primary primary screening protocol for cervical cancer in most regions of China, with a starting age of 21 years and an ending age of 65 years for cytologic screening. Direct colposcopy is recommended for women with LSIL and HSIL cytology; HPV testing can be used for triage or repeat cytology testing for ASC-US in women 25 years and older. Colposcopy is recommended if the HPV test is positive, and if the HPV test is negative, repeat the combined screening protocol at 3 years. When repeat cytology is chosen for triage, if repeat cytology is negative at 1 year, return to routine screening; if the result is ASC-US and above, colposcopy is recommended. ASC-US is treated differently in women aged 21 to 24 years, and repeat cytology at 12 months is preferred because HPV infection is mostly transient in women in this age group.
3.1.3 Application of high-risk HPV testing in primary screening for cervical cancer
With the publication of a large number of clinical trial data, there has been a change in the screening strategy for cervical cancer. 2008, the European Organization for Research on Reproductive Tract Infections and Neoplasms (EUROGIN) recommended high-risk HPV testing as primary screening for cervical cancer in Europe. 2015, 13 experts from various societies, including the American Society of Gynecologic Oncology (SGO) and the American Society for Colposcopy and Cervical Pathology (ASCCP), recommended the use of high-risk HPV testing for primary screening of cervical cancer in Europe. experts proposed a transitional guideline for cervical cancer screening in which high-risk HPV primary screening is used as an alternative to cervical cancer screening.
The starting age for high-risk HPV for primary cervical cancer screening is 25 years and the ending age is 65 years. Triage management for those with positive high-risk HPV test results is as follows: (1) Perform HPV 16 and 18 typing tests, and if HPV 16 or 18 is positive, colposcopy is directly recommended. (2) Apply cytology for triage if other high-risk types are tested positive. If the test result is ASC-US and above, colposcopy is performed directly; if the cytology test result is normal then follow up at 12 months. The interval between re-screening for those with negative high-risk HPV test results is currently recommended to be 3 years.
The main advantages of using HPV testing as a primary screening regimen for cervical cancer are: (1) HPV testing has higher sensitivity compared with cytologic primary screening, and has high sensitivity and high specificity for the diagnosis of CIN2 and above lesions. (2) HPV test primary screening has a higher negative predictive value, allowing for longer screening intervals and lower screening costs. However, the relatively low specificity and low positive predictive value of HPV testing primary screening leads to increased psychological stress and even trauma for the subject, high colposcopy rates, and even overtreatment.
3.2 Assessment of treatment outcome and post-treatment follow-up of cervical intraepithelial lesions
The incidence of recurrence, persistence and progression to invasive carcinoma is still higher than normal after reasonable and standardized treatment of cervical SIL. using HPVDNA testing can help determine whether the lesion is excised cleanly, predict the risk of lesion progression or recurrence after surgery, and effectively guide the postoperative follow-up of patients. persistent positive HPV indicates an increased chance of residual lesions or recurrence, and should be followed up closely and intervened early; while HPV-negative patients can The follow-up interval should be extended appropriately. It is recommended that HPV typing tests be used to determine whether HPV positivity is persistent infection or reinfection.
3.3 Evaluation of HPV vaccine efficacy
Currently, HPV vaccines in clinical use are mainly prophylactic vaccines, while therapeutic vaccines are still under development or in clinical trials. Prophylactic vaccines include quadrivalent vaccines (covering types HPV 16, 18, 6, and 11) and bivalent vaccines (covering types HPV 16 and 18). The nine-valent vaccine has recently been released and covers the types (HPV 16, 18, 31, 33, 45, 52, 58, 6 and 11), the evaluation of its effectiveness requires further clinical validation. HPV testing can be used to determine the efficacy of the vaccine and to understand the presence of other types of HPV infection, and HPV typing testing is recommended.
4. Diagnosis and treatment of HPV infection-related diseases
4.1 Diagnosis and treatment of condyloma acuminatum
4.1.1 Diagnosis of condyloma acuminatum
Condyloma acuminatum is a squamous epithelial proliferative wart-like lesion caused by HPV infection, which is common in young women aged 20 to 29. The diagnosis of condyloma acuminata is usually based on the typical lesions observed by the naked eye. The lesions are usually found near the navicular fossa, labia majora and minora, around the anus, vaginal vestibule, urethra, and may also involve the vagina and cervix.
The lesions start as single or multiple reddish papules with sharp apices and increase in size as the lesions progress; they may be papillary, cauliflower, coronary, or mass-like; they are often pink, gray, or tan in color; they are soft and brittle and may break down or become infected. 50% to 70% of vulvar warts are associated with vaginal or cervical warts. The actual fact is that you can find a lot of people who are not in a position to get a good deal on this. Ancillary tests include: cytology, acetic acid test, colposcopy, pathological examination and HPV nucleic acid test.
4.1.2 Treatment of condyloma acuminatum
There is no method to eradicate HPV. The treatment is only to remove the exophytic warts and improve the signs and symptoms. The treatment should be chosen according to the location, size and number of warts, whether the patient can self-medicate, economic status and the doctor’s experience.
(1) The treatment of external genital warts.
The actual fact is that you can find a lot of people who are not able to get a good deal on a lot of things. The foci can subside after 1~3 times of application. 6 times of application should be changed to other methods. c. 5% Imiquimod cream, 3 times a week, wash off after 6~10h of application, can be used for 16 weeks. Patients can self-administer the medication, mostly in 8~10 weeks after the medication warts fall off. This drug is a topical immunomodulator that works by stimulating the local production of interferon and other cytokines.
The actual physical or surgical treatment: physical treatment are microwave, laser, freezing. The number of acromegaly, the area is extensive or to other treatment methods failed acromegaly can be microwave or surgical excision.
(2) vaginal warts: 50% trichloroacetic acid or 10%-25% tincture of pediculosis toxin for external use, but also the choice of physical therapy, but the treatment to prevent mucosal damage. Liquid nitrogen freezing is not recommended because it may cause vaginal perforation and fistula formation.
(3) Cervical warts: before treating cervical warts, cytological examination, colposcopy and biopsy are needed to exclude cervical SIL and cervical cancer, there is no unified standard for the treatment of cervical warts, physical therapy, surgery or 50% TCA can be used depending on the condition.
(4) Sexual partner treatment: It is recommended that sexual partners be examined for warts at the same time, and sexual intercourse is prohibited until cured. Consistent and proper use of condoms can reduce the risk of warts, but there is still the possibility of HPV infection in areas not covered by condoms.
Follow-up is required after treatment, once every 2 weeks for 3 months after treatment. For recurrent recurrent condyloma acuminata, biopsy should be taken promptly to exclude malignant changes.
4.2 Treatment of cervical precancerous lesions
Currently, the principles of management of cervical precancerous lesions are based on the extent of lesions, age, cytological findings, HPV test results, transformation zone in colposcopy and the need to preserve reproductive function, etc., and then an individualized treatment plan is formulated. 2014 WHO made a new secondary classification of cervical precancerous lesions, CIN1 is equivalent to LSIL, CIN2 and CIN3 are equivalent to HSIL.
4.2.1 Management of CIN1
CIN1 mostly regresses spontaneously, especially in young women and pregnant women. The management of CIN1 is conservative and requires observation. Only a few cases persist for a longer period of time and require treatment. Currently, the management of CIN1, except for young women and pregnant women, needs to be evaluated in combination with previous cytology and HPV test results.
(1) For patients with CIN1 with cytology of ASC-US, LSIL or HPV testing for HPV16(positive), 18(positive) or persistent HPV infection: combined screening at 12 months is recommended, if all combined screening is negative, then age-based screening at 3 years, and if all screening is negative again at 3 years, return to routine screening. If the cytologic lesion is ASC-US and above or HPV positive, colposcopy will be performed.
(2) For CIN1 patients with cytologically detected high-grade squamous intraepithelial lesions (ASC-H) or HSIL, if colposcopy is adequate and cervical canal sampling is negative, diagnostic conization or combined screening at 12 months and 24 months is recommended, with referral for diagnostic conization if combined screening reveals one HSIL; if combined screening reveals HPV positivity or cytologic changes not If the combined screening reveals one HSIL, the patient is referred for diagnostic conization; if the combined screening reveals positive HPV or cytologic changes that do not reach HSIL, colposcopy is performed; if the combined screening is negative, the patient is rescreened at 3 years based on age. In addition, review of cytology, histology, and colposcopy results is acceptable for CIN1 patients with cytology detecting ASC-H or HSIL, and if the results of the review need to be revised, the revised results are treated as such.
The management of CIN1 is relatively conservative in young women aged 21 to 24 years and pregnant women, and management needs to be individualized.
4.2.2 Management of CIN2 and CIN3
The probability of CIN3 progressing to cancer is very high, and once diagnosed, it needs to be actively managed. Due to the poor consistency and reproducibility of CIN2 diagnostic results, the management of CIN2 is controversial at present.
CIN2 includes both neoplastic and non-neoplastic lesions (reactive squamous epithelial metaplasia, atrophy, and epithelial repair changes). In order to better differentiate neoplastic lesions, the 2014 WHO recommended the use of p16 immunohistochemical staining for the controversial diagnosis of CIN2 to improve the histological diagnosis of cervical lesions and the consistency of diagnosis between pathologists. p16-positive CIN2 is treated as CIN3, and p16-negative CIN2 is treated as CIN1.
In addition Ki-67 immunohistochemical staining is a more promising method in the triage of CIN2. Currently, some pathologists classify indistinguishable CIN2 and CIN3 as CIN2,3. The management of histologically diagnosed CIN2, CIN3 and CIN2,3 includes initial management and post-treatment follow up.
(1) Initial management: Except for young women and pregnant women, cervical conization or destruction treatment is possible if colposcopy is adequate. For recurrent CIN2, CIN3 and CIN2,3, inadequate colposcopy or cervical canal biopsy for CIN2, CIN3, CIN2,3 and unclassifiable CIN, diagnostic conization is recommended and destructive therapy is not recommended. In addition, hysterectomy is not the treatment of choice for CIN2, CIN3 and CIN2,3.
(2) Post-treatment follow-up: combined screening at 12 and 24 months after treatment is recommended, with re-screening at 3 years if combined screening is negative; colposcopy with cervical canal sampling is recommended if any result is abnormal in combined screening; if all screening is negative, at least 20 years are still needed before returning to routine screening, even if the age is over 65 years. Cytology and cervical canal sampling are recommended at 4 to 6 months after treatment for positive cut margins or for CIN2, CIN3 and CIN2,3 on cervical canal sampling. In addition, repeat diagnostic conization is acceptable, and if repeat diagnostic conization is not feasible, hysterectomy is also acceptable.
The management of CIN2, CIN3 and CIN2,3 in young women aged 21-24 years is relatively conservative and needs to be individualized.
4.3 Management of cervical cancer, vulvovaginal SIL and vulvar cancer
The management of cervical cancer, vulvovaginal SIL and vulvar cancer mainly refers to the Chinese Medical Association Gynecologic Oncology Branch, Guidelines for the diagnosis and treatment of common gynecologic malignancies, 4th edition, 2014; National Comprehensive Cancer Network (NCCN) guidelines for the diagnosis and treatment of cervical cancer, 2015, and the International Federation of Gynecology and Obstetrics (FIGO) guidelines for the diagnosis and treatment of cervical cancer, 2012.