Cervical intraepithelial neoplasia (CIN) grade 1, 2, 3, 4

The growth of abnormal cells within the tissue of the CERVIX. Because without treatment CIN often progresses in severity and is the foundation of CERVICAL CANCER, doctors consider CIN a precancerous condition and grade it according to the extent to which it infiltrates the cervix. The four grades, or levels of severity, of CIN are

  • grade 1, or CIN1, in which the abnormal cells infiltrate only the first layer of tissue; CIN1 often goes away on its own though merits careful observation until it is clear that it has done so
  • grade 2, or CIN2, in which the abnormal cells penetrate to the second or third layer of tissue; standard treatment is surgical removal of the affected tissue using the loop electrosurgical excision procedure (LEEP)
  • grade 3, or CIN3, in which the abnormal cells penetrate through the third layer of tissue and involve a fairly substantial area of cervical tissue; standard treatment is surgical removal of the affected tissue, usually using LEEP and sometimes using conization
  • grade 4, or carcinoma in situ, in which the abnormal cells completely penetrate all epithelial layers using conization

Though CIN often follows an orderly progression from grade 2 to grade 4, culminating with cervical cancer, it does not always do so. About a third of CIN2 and CIN3 progresses to the next level and three fourths of women who have CIN4 or carcinoma in situ eventually develop cervical cancer. However, CIN1 progresses to cervical cancer in only 1 percent of women.

Symptoms of Cervical intraepithelial neoplasia (CIN) and Diagnostic Path

Often a woman has no symptoms of CIN; the doctor detects the condition during routine PELVIC EXAMINATION and PAP TEST. COLPOSCOPY (examination of the cervix with a lighted surgical microscope) can sometimes confirm the diagnosis. However, excisional biopsy (removal of the abnormal area and laboratory examination of the tissue) is the definitive diagnostic procedure.

Cervical intraepithelial neoplasia Treatment Options and Outlook

Standard treatment for CIN is removal of the abnormal cells with follow-up pelvic exam, Pap test, and other pathologic tests. The procedures for removal include

  • LEEP, an office procedure in which the gynecologic surgeon inserts a wire loop through the VAGINA to the cervix and removes slices of tissue by sending a mild electrical current through the wire loop; LEEP is the standard treatment for CIN2 and some CIN3
  • conization, also called excisional conization or cone biopsy, in which the gynecologic surgeon removes larger areas of tissue with instruments inserted through the vagina; the woman usually undergoes general ANESTHESIA, and the procedure is performed in an operating room

These treatments usually cure the CIN, though doctors recommend regular follow-up Pap tests, colposcopy, and other laboratory tests for up to five years after the initial treatment.

Risk Factors and Preventive Measures

The strongest risk for CIN is INFECTION with HUMAN PAPILLOMAVIRUS (HPV). CIN is more common in women who smoke and in women who have HIV/AIDS. A Pap test can detect CIN in its early, easily treatable stages. Preventive measures include safer sex methods (such as abstinence, condom use, or mutually monogamous sexual relationships) to prevent HPV infection. In 2006 the first vaccine to prevent HPV infection in women became available. The vaccine protects against infection with HPV types 6, 11, 16, and 18, the types associated with genital warts and cervical cancer. Health experts recommend HPV vaccination for girls beginning at age 12, though women to age 26 can receive the vaccine.


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