Colposcopy is a gynecological endoscope, mainly used in the auxiliary diagnosis and evaluation of intraepithelial neoplasia, early cervical cancer and other early lesions of the lower genital tract. Cervical cancer patients should undergo colposcopy and biopsy. The accuracy of diagnosing cervical cancer and its precancerous lesions can reach 98%-99.4%.
The main factors affecting the accuracy of colposcopy
1. Patient age and hormone levels affect squamous epithelium thickness
Thinner squamous epithelium during perimenopause or when hormone levels are low increases the risk of missing HSIL. Studies have shown that the sensitivity of colposcopy in diagnosing CIN 2 and 3 varies with the average thickness of cervical epithelial lesions, and the sensitivity increases from 31.3% when the epithelial thickness is 0-139 μm to 291-441 μm when the epithelial thickness is 291-441 μm. of 94.4%.
2. The extent of cervical lesions involved
Occult lesions with small lesions are more difficult to diagnose.
3. Adequacy of colposcopy
The presence of endocervical lesions and the need for ECC were associated with the accuracy of colposcopy point biopsy.
4. HPV types
Compared with squamous cell carcinoma, HPV16 infection is the majority, and HPV18 infection is more common in adenocarcinoma, and it is mostly related to endocervical lesions, which is difficult to detect.
5. Occult and insignificant glandular epithelial lesions lead to adenocarcinoma in situ (AIS) of the cervix
Occult lesions that are prone to miss diagnosis account for about 60% of AIS, even though 85% of AIS on the epithelial surface of the transformation zone resembles immature squamous metaplasia or inconspicuous red and white. 37% of AIS were discovered accidentally during the surgical treatment of HSIL. The sensitivity of colposcopy to detect AIS was only 9.8%, with a negative predictive value of 12.5%.
6. The accuracy of colposcopy
Influenced by the experience of colposcopy doctors and the standardization of operating procedures, the professional training of colposcopy doctors is particularly important. A prospective study of 3 senior and 3 junior colposcopy physicians (with at least 5 years of experience) was conducted to assess the grading and diagnostic power of colposcopy for HSIL lesions, which were 73.7% and 48.4%, respectively (P=0.03).
7. Number of biopsies
Studies have shown that single-point biopsy of the cervix can lead to missed diagnosis of HSIL+. The detection rate of HSIL+ in single-point biopsy was 60.6%-68.3%, 2-point biopsy was 81.8%-85.6%, 3-point biopsy was 83.3%-95.6%, and 4-point biopsy was 100%. Targeted multi-site localization biopsy is different from random biopsy, which refers to the targeted biopsy of any area of visible changes, including acetowhite changes, metaplasia, and other abnormal changes. With the increase of cervical biopsy samples from 1 point to 2 points and 3 points, it was found that the sensitivity of HSIL+ increased significantly, but the additional random biopsy had no obvious benefit in improving the detection rate of HSIL+. The 2017 ASCCP colposcopy standard recommends that targeted 2- to 4-point localized biopsy in obvious acetowhite areas is superior to single-point biopsy and random biopsy without significantly increasing the bleeding rate and infection rate