Monday, June 22, 2020

Cervical cancer screening

What is cervical cancer?

Cervical cancer is the second highest incidence of female malignant tumors. New data from the China Anti-Cancer Association shows that there are 140,000 new cervical cancer patients in my country every year and the number of deaths is 37,000 per year. Fortunately, the disease is a preventable and curable disease, the main cause of which is the persistent infection of high-risk HPV (human papillomavirus). HPV can be detected in 99% of cervical cancer patients, especially the high-risk type HPV16 and 18 subtypes. Under the continuous infection of the virus, normal cervical cells gradually develop into precancerous lesions, and finally into cervical cancer. Once they develop into high-grade precancerous lesions and carcinogenesis, all we can do is based on the pathological classification of the diseased tissue Surgery or chemotherapy has seriously affected the patient's quality of life, and even life-threatening.

About HPV

HPV is a double-stranded DNA virus, mainly transmitted sexually. It has more than 100 family members. At present, 13 of them are found to be closely related to the occurrence of cervical cancer. We call it high-risk HPV. The study found that the infection rate of HPV in the population is as high as 80%, especially those with active sexual life, but most of the infections will not cause disease, because almost all viruses are cleared by the body's immune system within 1 to 2 years, and There is no tumor-like change, so when you know that you have an HPV infection, you don’t need excessive tension and panic. Cervical cancer occurs only when persistent infection of high-risk HPV (HPV-positive tests twice a year apart) occurs, and this probability is also relatively small. Unfortunately, like most viruses, there are currently no special anti-HPV drugs and other effective means to remove the virus, so once infected with the virus, in addition to paying attention to the usual lifestyle (avoid sexual promiscuity), improve body immunity, We will have no more ways to deal with it. The good news is that the development of the HPV vaccine has brought light to many female friends. A large number of clinical trials at home and abroad have found that the HPV vaccine has a definite effect on the prevention of HPV infection, but it does not clear the existing HPV. Women who have sex with sex have an important preventive effect. The recommended age for vaccination is 9-26 years old. Before the first sex, the earlier the vaccination is, the higher the prevention effect will be. Once the sex is started, the risk of infection will increase greatly. At this time, the effect of vaccination will not be particularly significant. In addition, being vaccinated does not mean that you will not be infected with HPV again, because the three vaccines currently on the market cannot cover all types of high-risk HPV, so regular cervical cancer screening is also required after vaccination.

Cervical cancer screening

After the above description, I believe we have a certain understanding of the disease. Understanding the disease is of course to better prevent and cure the disease. This article will elaborate from the following aspects.

Screening methods

Cytological examination: such as liquid-based thin-layer cytology (TCT), cervical cytology examination as the main method of cervical cancer screening, the world's most widely used. But its shortcomings are its poor sensitivity (about 50%) and the high rate of specimen failure.

HPV-DNA testing: viral DNA testing, high sensitivity, high negative predictive value.

Specific screening frequency

Women aged 21 to 29 should undergo cervical cytology examinations every 3 years. For women aged 30-65 years, combined screening with cytology and HPV is preferred, once every 5 years; cytology screening can also be performed once every 3 years. For women whose previous screening results were clearly negative and no CIN2 or higher lesions, any screening should be stopped after the age of 65. Previous screening results clearly defined as having three consecutive negative cytology or two consecutive The combined test results were negative, and the most recent screening was conducted within the past 5 years. Women with a previous history of CIN2, CIN3, or adenocarcinoma in situ should continue screening for 20 years after the disease has subsided naturally or after clinical treatment, and even extend the screening to beyond 65 years of age.

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