We estimated the overall and type‐specific prevalence of human papillomavirus (HPV) and p16 overexpression in vaginal cancer and vaginal intraepithelial neoplasia (VaIN). We conducted a systematic search of PubMed, Embase and Cochrane Library to identify studies published between 1986 and 2017 using PCR‐based or Hybrid Capture 2 tests to evaluate the presence of HPV DNA and/or using any method to detect p16 overexpression in VaIN, vaginal squamous cell carcinoma (VaSCC), or other types of vaginal cancer. Applying a random effects model, we estimated the pooled prevalence of HPV and p16 overexpression along with 95% confidence intervals (CIs). The I2 statistic was used to assess heterogeneity. We included 26 studies, reporting HPV prevalence and six studies evaluating p16 overexpression. The pooled HPV prevalences in VaSCC (n = 593) and VaIN (n = 1,374) were 66.7% (95% CI = 54.7–77.8) and 85.2% (95% CI = 78.2–91.0), respectively. Substantial inter‐study heterogeneity was observed, and analyses stratified on geographic region, type of tissue, HPV detection method or PCR primer type did not fully explain the observed heterogeneity. The most predominant HPV type among the HPV positive VaSCC and VaIN cases was HPV16, followed by HPV33, and HPV45 (in VaIN) and HPV18, and HPV33 (in VaSCC). In pooled analyses, 89.9% (95% CI = 81.7–94.6) of HPV positive and 38.9% (95% CI = 0.9–90.0) of HPV negative vaginal cancers were positive for p16 overexpression. Our findings suggest that vaccination against HPV might prevent a substantial proportion of vaginal neoplasia and highlight the need for further studies of the possible clinical value of p16 testing in these patients.

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Introduction Human papillomavirus (HPV), p16, and p53 have been investigated as prognostic markers in various HPV‐related cancers. Within the field of vaginal cancer, however, the evidence remains sparse. In this systematic review, we have compiled the presently published studies on the prognostic significance of HPV and immunohistochemical expression of p16 and p53 among women with vaginal cancer. Material and methods We conducted a systematic search of PubMed, Embase, and Cochrane Library to identify relevant studies published until April 2021. We included studies reporting survival after histologically verified vaginal cancers tested for HPV, p16, and/or p53. Survival outcomes included overall survival, disease‐free survival, disease‐specific survival, and progression‐free survival. Results We included a total of 12 studies. The vast majority of vaginal cancer cases included in each study were squamous cell carcinomas (84%–100%). Seven studies reported survival after vaginal cancer according to HPV status, and the majority of these studies found a tendency towards improved survival for women with HPV‐positive vaginal cancer. Three out of four studies reporting survival according to p16 status found an improved survival among women with p16‐positive vaginal cancer. For p53, only one of six studies reported an association between p53 expression and survival. Conclusions This systematic review suggests that women with HPV‐ and p16‐positive vaginal cancer have an improved prognosis compared with those with HPV‐ or p16‐negative vaginal cancer. Results for p53 were varied, and no conclusion could be reached. Only 12 studies could be included in the review, of which most were based on small populations. Hence, further and larger studies on the prognostic impact of HPV, p16, and p53 in vaginal cancer are warranted.