1.The significance of screening
Cervical cancer screening can effectively reduce the incidence and mortality rate of cervical cancer. In countries or regions where screening systems are well established, such as North America, Australia and Europe, the incidence and mortality rates of cervical cancer have decreased significantly. In developing countries, however, cervical cancer incidence and mortality have not improved significantly. In China, the incidence of cervical cancer in some large cities where large-scale cervical cancer screening has been conducted, such as Beijing, Shanghai and Tianjin, is much lower than that in other parts of the country.
Performing cervical screening can detect early lesions. Cells on the surface of the cervix proliferate abnormally in response to carcinogenic factors and go through a precancerous stage, known as cervical intraepithelial neoplasia (CIN), to develop into cervical invasive cancer, a process that takes approximately several years. The fact that the cervix is located at the top of the vagina and can be visualized through gynecological examination provides a very favorable opportunity for cervical screening. If a woman undergoes regular cervical screening, it is entirely possible to detect lesions at the precancerous stage, and if the precancerous lesions are treated appropriately, they will be effectively prevented from developing into cervical cancer. It can be said that if a woman can attend regular cervical screening and receive appropriate treatment when precancerous lesions are detected, she will not develop cervical cancer in her lifetime; if every woman has regular screening, cervical cancer will probably disappear from the disease spectrum. All women are urged to take the initiative to participate in cervical screening and share the benefits of screening with the “her” around you.
2. Screening methods
Screening refers to the detection of cancer by certain methods before it shows obvious symptoms, and it can detect early cancer or even precancerous lesions. Screening for cervical cancer includes cervical cytology and human papillomavirus (HPV) testing, the former commonly used methods include traditional Pap smear (commonly known as cervical smear) and liquid-based thin layer cytology (TCT).
(1) After exposing the cervix with a speculum, the traditional Pap smear doctor gently scrapes the secretions and cells from the surface of the cervix with a small wooden plate, coats them on a glass slide, and observes them under a microscope after fixation and staining with a view to detecting cancerous or abnormally proliferating cells. This method may be affected by mucus, cell overlap and cell loss during the process of filming, which reduces the chance of detecting abnormal cells by the doctor reading the film.
(2) Liquid-based thin-layer cytology (TCT) This method involves the physician exposing the cervix with a speculum and then using a cervical sampling brush to brush the cervical cells and elute them in a special fixative, followed by centrifugation and stratification techniques to distribute the cells in a single layer on a slide for observation under a microscope. The advantages of this method are that the cells are distributed in a single layer, the influence of mucus is excluded, and the abnormal cells are easily detected by the film reader with high sensitivity.
(3) HPV testing is now clear that persistent high-risk HPV infection is the ultimate cause of cervical cancer. The high-risk HPV testing technology currently used has a higher sensitivity than cytology, and the sensitivity of high-risk HPV testing combined with cytology can reach 100%. Therefore, experts recommend that HPV testing be used for initial screening and that cytology be performed on women who test positive for high-risk HPV. Sensitive A ground is coated on a glass slide, fixed by alcohol and stained to find cancer or atypia under the microscope.
3.What should be noted before and after the screening test
(1) If there is vaginitis, it should be treated before cervical smear examination.
(2) Avoid vaginal douching, drugging and sexual intercourse within 48 hours before the examination.
(3) The examination should be avoided during menstruation.
(4) There may be a small amount of vaginal bleeding after the cytology and HPV tests, which usually disappears after a day or two and is not a cause for concern.
(5) After obtaining the test report, you should consult with your doctor if further tests are needed and keep in mind the time of the next test.
4. Some questions about cervical cancer screening
(1) Which women need to be screened
Women who have a history of sexual intercourse for more than 3 years and women under 65 years old should undergo cervical screening.
(2) How often should screening be performed?
If the cytology and HPV test are negative, the next screening can be done after 5 years; if only cytology is done and the result is not abnormal, the screening can be done again after 3 years.
(3) Where to get screened
Screening methods such as cervical smear, TCT, and HPV testing all include two processes: sampling and specimen testing. Sampling, in which a physician removes a specimen from a woman’s cervix with a specimen brush or scraper and stores it, can be done at all levels of hospitals and health screening centers.
Cervical cytology is now available in most hospitals. Some hospitals send the collected specimens to certain testing centers or larger hospitals for production, reading and report issuance. Because cytology depends on the pathologist reading the specimens, the accuracy of the test depends on the quality of the film and the experience of the reader, so the results are more reliable when the cytology specimens are performed in a specialized hospital or a large general hospital. The recommended clinical method for detecting high-risk HPV is the HC-2 method (second-generation hybridization capture method), which has little human influence and more objective results, and the accuracy of the test is consistent from hospital to hospital. At present, this instrument is only available in larger hospitals and testing centers.
(4) Does cervical cancer screening cause pain?
The sampling process of screening is non-invasive and since the cervical area is not sensitive to pain, cervical smear or HPV test sampling does not cause significant discomfort, much less pain.
(5) Do you still need to be screened after a hysterectomy?
There are two types of hysterectomy: total hysterectomy (where the cervix is removed) and subtotal hysterectomy (where the cervix is preserved). If a total hysterectomy was performed for reasons unrelated to cervical pathology, and the pathology after the surgery determines that there is no cervical pathology, no postoperative screening is necessary, but regular follow-up is still required by the physician. Those who have undergone subtotal hysterectomy for whatever reason and whose cervix is still preserved should still attend cervical screening regularly.
(6) Can pregnant women be screened for cervical cancer?
It is safe to perform cytology and HPV testing at the time of pregnancy. Women who are due for re-screening or who have never had cervical screening can be screened at the time of pregnancy. At the time of sampling, women should indicate their weeks of pregnancy to the sampling physician.
5. Cost of screening
Traditional cytology smears cost $30-50/visit; liquid-based cytology is $250-270/visit; and HPV testing is $350/visit. A more economical and inexpensive HPV test is being developed.