The Vaginal Microbiota, Human Papillomavirus Infection, and Cervical Carcinogenesis: A Systematic Review in the Latina Population

BACKGROUND

Latina women experience disproportionately higher rates of HPV infection, persistence, and progression to cervical dysplasia and cancer compared to other racial-ethnic groups. This systematic review explores the relationship between the cervicovaginal microbiome and human papillomavirus infection, cervical dysplasia, and cervical cancer in Latinas.

METHODS

The review abides by the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. PubMed, EMBASE, and Scopus databases were searched from January 2000 through November 11, 2022. The review included observational studies reporting on the cervicovaginal microbiota in premenopausal Latina women with human papillomavirus infection, cervical dysplasia, and cervical cancer.

RESULTS

Twenty-five articles were eligible for final inclusion (N = 131,183). Forty-two unique bacteria were reported in the cervicovaginal microbiome of Latinas. Seven bacteria: Lactobacillus crispatus, Lactobacillus iners, Chlamydia trachomatis, Prevotella spp., Prevotella amnii, Fusobacterium spp. and Sneathia spp. were enriched across multiple stages of cervical carcinogenesis in Latinas. Therefore, the total number of reported bacteria includes four bacteria associated with the healthy state, 16 bacteria enriched in human papillomavirus outcomes, 24 unique bacteria associated with abnormal cytology/dysplasia, and five bacteria associated with cervical cancer. Furthermore, three studies reported significantly higher alpha and beta diversity in Latinas with cervical dysplasia and cancer compared to controls. Lactobacillus depletion and an increased abundance of L. iners in Latinas compared to non-Latinas, regardless of human papillomavirus status or lesions, were observed.

CONCLUSIONS

The identification of 42 unique bacteria and their enrichment in cervical carcinogenesis can guide future cervicovaginal microbiome research to better inform cervical cancer prevention strategies in Latinas.

Effect of cervical disease history on outcomes of women who have a pap diagnosis of atypical glandular cells of undetermined significance

OBJECTIVE

To determine the relationship between history of cervical dysplasia or carcinoma and the development of cervical dysplasia or adenocarcinoma in women who have a diagnosis of atypical glandular cells of undetermined significance (AGUS), favor endocervical origin, or AGUS, not otherwise specified.

METHODS

A 6-year retrospective review of the pathology files was performed for 93 women who were diagnosed in 1992 with AGUS, favor endocervical origin, or AGUS, not otherwise specified. Data collected included previous history of cervical disease, follow-up diagnoses, time interval between follow-ups, and procedures performed.

RESULTS

Of women with follow-up who had or did not have a previous history of cervical dysplasia, 32.0 and 12.0%, respectively, developed a squamous dysplasia or adenocarcinoma in situ. This difference was statistically significant (P<0.05). Of the women who had or did not have a previous history of cervical dysplasia and had Pap smear follow-up, only 4.2 and 4.3%, respectively, had a false-negative diagnosis on the most immediate subsequent smear.

CONCLUSIONS

Women who have AGUS, favor endocervical origin, or AGUS, not otherwise specified, and no history of cervical dysplasia have a significantly lower risk of developing or having cervical dysplasia than women who have the same diagnosis and a history of cervical dysplasia. This may warrant different treatment protocols for these two groups. For the women with AGUS and no previous history of cervical dysplasia, a repeat Pap smear, rather than colposcopy with curettage, may be warranted.

Long-term outcome and relative risk in women with atypical squamous cells of undetermined significance

Few studies have compared long-term follow-up and risk for invasive cancer in women with atypical squamous cells of undetermined significance (ASCUS). We conducted a 6-year review of pathology files for 651 women in whom ASCUS had been diagnosed in 1992. Data collected included patient demographics, follow-up diagnoses, time between follow-up examinations, and procedures performed. At follow-up, high-grade squamous intraepithelial lesions (HSIL) had developed in 9.0% of the women, and invasive cancer in none. Previous cervical history did not affect risk for an HSIL. Although the average time to first follow-up was 6.18 months, in 20.9% of the women the diagnosis of HSIL was not established until after 2.0 years. For individual pathologists, the percentage of HSILs ranged from 0% to 18.8%. Thus women with ASCUS who are followed up regularly are at low risk for development of invasive cancer.

Cost effectiveness of rescreening cervicovaginal smears

Although cytology laboratories are mandated to rescreen at least 10% of cervicovaginal smears, there is no uniform national rescreening practice. Follow-up data for 16,188 rescreened cervicovaginal smears were studied and decision analysis was performed to determine an optimal rescreening strategy. High-grade dysplasia was detected in 0.40% of women with a history of cervical disease and in 0.04% without a history of cervical disease. Compared with 0% rescreening of smears, with 15% rescreening the cost to gain a year of discounted life expectancy was $386,890 for women without a history of cervical disease, and $2,980 for women with a history of cervical disease. We conclude that rescreening only smears from women with a history of cervical disease could save US laboratories more than $11.2 million annually without seriously compromising care.