This retrospective study reminds us that development of intraepithelial neoplasia of the lower genital tract is the result of the sexually transmitted human papilloma-virus (HPV), which, at least theoretically, can exert a malignant-field eff ect.
The cervix is most susceptible at the transformation zone, but the remainder of the squamous epithelium of the lower genital tract may be at risk in susceptible persons.
What is the residual risk?
Who should we watch?
If the cervix is removed during hysterectomy after CIN 2+ is diagnosed, what is the residual risk to the patient? How should she be managed?
These are key questions, despite the fact that hysterectomy is not as commonly performed to treat high-grade CIN as it is for other indications, such as abnormal bleeding, pain, endometriosis, and fibroids. Hysterectomy for these other conditions without a concomitant history of neoplasia obviates the need for cervical cancer screening via cytology or HPV testing, or both. When CIN is the reason for the hysterectomy, however, or the patient has a history of CIN 2+, there is some residual risk, with the most common sequela being VAIN and, if the VAIN remains undiscovered, vaginal carcinoma. But how do we identify the patient at high risk for VAIN so that we can provide extra resources (screening or colposcopy services)?
Older women merit closer attention
One strength of this study is the fact that it statistically identifiled “older women” as a high-risk subset more likely to develop VAIN 2+. In the study, the mean age of women who were likely to develop VAIN 2+ was 61 years, compared with 46.9 years for women likely to remain free of disease.
The median interval between hysterectomy and diagnosis of VAIN 2+ was 35 months (range, 5–103 months). This information allows us to anticipate an optimal window in which to focus extra screening.
Retrospective design is a weakness
The retrospective design of this review of pathology data from multiple practices in multiple records is a limitation. The exclusion of patients who had coexisting VAIN or a history of VAIN is laudable, but bias is possible. The quality of the documentation of examination of the remainder of the lower genital tract in patients who had abnormal cervical screening during colposcopy (which led to the diagnosis of CIN) is subject to extreme variability, compared with a prospective design that would have defined the elements of vaginal and vulvar colposcopic examination.
In other words, I am concerned that these are truly incident—rather than persistent—lesions following hysterectomy.
How would HPV testing come into play?
This study and the other published studies that address the subject of hysterectomy in the treatment of CIN 2+ did not use HPV testing. If they had, it likely would have provided more information about the true risk of recurrence and helped determine the best screening interval.
The American Society for Colposcopy and Cervical Pathology (ASCCP) guidelines from 2006 do not address this particular scenario, but American College of Obstetricians and Gynecologists (ACOG) guidelines do recommend annual Papanicolaou testing following hysterectomy for CIN until three consecutive tests are negative.1
How reliable are screening methods when the vagina is the target tissue?
Cytologic sampling, HPV test sampling, and colposcopy of the “at-risk” transformation zone or endocervical canal are easier to accomplish than are examination and testing of the entire vaginal vault. The latter are more prone to error and lack evidence-based data to substantiate our practice.
Nevertheless, excellent practice recommendations regarding vaginal colposcopy can be found at the ASCCP Web site at www.asccp.org/edu/practice/vagina.shtml.
WHAT THIS EVIDENCE MEANS FOR PRACTICE
We should always carefully examine the entire lower genital tract during colposcopy following referral for abnormal cytology or another abnormal screening test—whether or not the patient has a cervix.-NEAL M.LONKY, MD, MPH