Carbon Dioxide Laser Surgery in Gynecology Workup

Updated: Sep 20, 2018
  • Author: Janice L Bacon, MD; Chief Editor: Christine Isaacs, MD  more...
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Laboratory Studies

The Papanicolaou test has been the initial screening test for cervical cytologic abnormalities. It is a cost-effective cancer screening tool. Population screening has clearly led to a decline in the incidence of cervical carcinoma. However, by definition, it is a screening tool with a specificity of 95% and a sensitivity of 51%. [28]

  • The specimen is obtained with an appropriate collection device (brush combined with spatula, or broom with or without spatula). The specimens should be representative of the entire transformation zone.

  • The samples obtained may be smeared on a glass slide and sprayed with cell fixative or placed in a liquid-based medium for later cell preparation. The liquid-based evaluation technique may allow the sample to be used for more than cytologic testing. Additional studies that can be performed on the sample may include HPV typing or testing for gonorrhea, chlamydia, or herpes. Future improvements on liquid-based cytology may even allow testing for some other medical diseases.

  • Infection with human papilloma virus has been clearly linked to intraepithelial lesions of the cervix and anus, and to a large proportion of vulvar and vaginal intraepithelial abnormalities. Most HPV infections are transient and no longer detected within 1-2 years. Women with persistent HPV infection, however, are at risk of developing premalignant lesions. Persistent disease, especially with HPV 16 increases the long-term risk of intraepithelial lesions or malignancy. [26, 29]

  • Development of molecular tests for HPV assist with identifying women whose HPV infections may warrant closer surveillance for dysplasia. Identification of HPV genotypes can also assist with targeted care for prevention of malignancy. The use of cytologic evaluation and HPV co-testing have improved the sensitivity of detection of intraepithelial lesions while providing greater reproducibility.

Vaginal cytologic abnormalities may be detected with Papanicolaou testing or by visual inspection. The colposcope may be used for screening women with intraepithelial neoplasia abnormalities on the genitalia or cervix when visual inspection identifies a lesion or cytology reveals squamous abnormalities.

Vulvar lesions are usually identified by visual inspection following a history of condylomata or intraepithelial neoplasia elsewhere in the genitalia or upon patient complaints of irritation, itching, or a change in skin appearance (raised lesion, red lesion). The colposcope with use of adjunctive acetic acid may identify additional areas of VIN. Cytologic testing by traditional cytologic smear or liquid-based cytology is not indicated and is insufficient for diagnosis on the vulva. A possible exception is cytologic screening of the squamous tissue of the anus and the squamocolumnar junction of the anus and rectum. Colposcopy improves the inspection of the anus and rectum if symptoms are present or a lesion is seen.

All abnormal areas identified require biopsy if malignant or premalignant findings are suspected. Exclusion of malignancy is required prior to medical or surgical therapy.

Additional preoperative laboratory evaluations may be performed to ensure patient safety during anticipated anesthesia, especially in patients with a complex medical history (eg, cardiovascular disease, hypertension, diabetes).


Other Tests

Today there is better understanding of the role of persistent high risk HPV in the development of premalignant and malignant lesions of the anogenital tissues. In the cervix, persistent high risk HPV infections are associated with CIN 3 (severe dysplasia, HSIL) and cancer. Epidemiologic research has shown that HPV 16 and 18 are the most carcinogenic types in the female genital tissues, with HPV 16 associated with 55-60% of cervical cancers and HPV 18 associated with an additional 10-15% of cervical malignancy. These HPV types are also the most oncogenic subtypes identified in malignant and premalignant squamous lesions of the vagina, vulva and anus in women. [30, 31, 32]

Cytology is imperfect in its delineation of lesions with present or future malignant potential and thus the use of molecular tests has been employed. These currently have increased sensitivity, but lower specificity for detection of high risk lesions. Testing for high risk HPV subtypes combined with cytologic screening, co-testing, has the potential for increased disease detection while also allowing increased screening intervals for appropriate women. [33, 34, 35]

Three categories of HPV testing are available: HPV DNA testing, (testing for high or low risk subtypes or genotyping HPV 16, 18) HPV RNA testing (detecting expression of E6 and /or E7 RNA), or detection of cellular markers- particularly cellular p16 protein which is increased when HPV E7 protein disrupts cell cycling and may improve detection of high-grade CIN while excluding immature squamous metaplasia. 

No laboratory tests for adhesions or endometriosis are currently available. Ca-125 levels may be elevated in some women with severe endometriosis, but findings are not specific enough for use as a diagnostic test. Many other disease processes elevate Ca-125 levels, rendering this test unsuitable for screening.



Diagnostic Procedures

Preparation for CO2 laser therapy of dysplasia of the cervix, vulva, or vagina includes the following:

  • Reviewing results from cytology; colposcopic examination of the cervical transformation zone, vulva, or vagina; and indicated biopsies to ensure that malignancy is not present.

  • Visualizing the full extent of a lesion and ascertaining it is within the planned area of ablation or excision.

  • Choosing an alternate procedure if these criteria are not met. Lesions of the cervix considered for excision by laser conization alternatively may be considered for a LEEP or a cold-knife conization procedure.

The following steps should be taken prior to using the CO2 laser in the pelvis.

  • Preoperative clinical plans should fully assess the cause of symptoms. All pelvic structures, including the bowel, bladder, internal genital structures, and musculoskeletal system must be considered as possible sources of pain or disease and a decision should be made when to proceed to operative evaluation.

  • Intraoperative evaluation of pelvic pain should include careful laparoscopic inspection of the entire pelvis.

  • The risks and benefits of both diagnostic laparoscopy and intrapelvic CO2 laser ablation and/or excision must be reviewed by the physician with the patient prior to the procedure. The discussion of the extent of the operative procedure planned should be included.