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CIN grading revealed: Why do some cells become abnormal?
Cervical intraepithelial neoplasia (CIN), also known as cervical dysplasia, refers to the abnormal proliferation of cells on the surface of the cervix, which may lead to the development of cervical cancer. CIN mainly occurs at the squamocolumnar junction of the cervix, which is the transition area between vaginal squamous epithelium and internal cervical columnar epithelium. Depending on the degree of abnormality, CIN is divided into grades 1 to 3, with grade 3 being the most serious. Human papillomavirus (HPV) infection is necessary to cause CIN, but not all infected people will develop cervical cancer. After most women are infected with HPV, their immune system will clear the virus on its own. Only women whose infection lasts for more than one or two years need special attention.
"Most cases of CIN stabilize or resolve spontaneously without intervention by the patient's immune system. However, if left untreated, a small number of cases may develop into cervical cancer."
Signs and symptoms
CIN itself has no specific symptoms. In general, signs and symptoms of cervical cancer include: abnormal or postmenopausal bleeding, abnormal discharge, changes in urinary or bowel movements, pelvic pain during examination, and abnormal appearance or palpation of the cervix.
"Persistent HPV infection may cause cells to become cancerous, but most infected people will not develop CIN or cancer."
Cause
The main cause of CIN is persistent HPV infection, especially high-risk virus types 16 or 18. These high-risk HPVs have the ability to inhibit tumor suppressor genes such as p53 and RB genes, allowing infected cells to grow uncontrollably and accumulate mutations that may ultimately lead to cancer. Certain women are more likely to develop CIN, such as those with high-risk HPV infection, immune deficiency, poor diet, too many sexual partners, and smoking.
Pathophysiology
The early microscopic changes of CIN are abnormal changes in the cells on the surface of the cervix. Usually these changes are not detectable by women. Most abnormal changes occur at the squamocolumnar junction, known as the transformation zone. In CIN, cellular changes associated with HPV infection such as koilocytic changes are also common. Although HPV infection is critical to the development of CIN, most infected individuals do not develop high-grade intraepithelial lesions or cancer.
"Currently, there are more than 100 different types of HPV, about 40 of which are known to affect the genital epithelium and have different possibilities for malignant changes."
Diagnosis
An HPV test called the Digene HPV test can accurately confirm the diagnosis and complement the cytology test (Pap test). This test is used primarily to collect a sample of cells, and standard disease detection methods include cervical endoscopy and targeted biopsies. In addition, a biopsy of the cervix requires histological analysis to confirm the diagnosis of CIN or cervical cancer.
Examination classification and treatment
Historically, abnormal changes in cervical epithelial cells have been classified as mild, moderate, and severe. The above changes were standardized in the "Bethesda System" proposed by the National Cancer Institute in 1988. The system has redefined CIN exceptions. With CIN 1, in most cases the disease will not require immediate treatment but rather regular monitoring, as most mild lesions will resolve themselves within a short period of time.
"For high-grade lesions with CIN 2 and above, surgical resection is usually required, using techniques such as cold cautery, electrocautery, laser, and circular electrotomy."
Treatment and prognosis
Treatment of CIN depends on the grade of the disease. Usually CIN 1 does not require prompt treatment, while CIN 2 and above may require cutting-edge surgery. Over time, 70% of CIN 1 cases will resolve naturally within a year, and 90% will disappear within two years. However, approximately 11% of CIN 1 and 22% of CIN 2 cases will progress to CIS without treatment.
Epidemiology
In the United States, 250,000 to 1 million women are diagnosed with CIN each year, and screening can detect high rates of the condition in women between the ages of 25 and 35. According to current estimates, the annual incidence of CIN 1 among screened women is approximately 4%, while CIN 2 and CIN 3 are 5%.
After understanding the development of CIN and its risk factors, do you have a new understanding and thinking about your health status?
