SEXUALLY-TRANSMITTED AGENTS AND RISK OF CARCINOMA OF THE VAGINA

A case-control serologic study was conducted to examine the involvemen t of sexually transmitted agents (STAs) in the rare occurrence of vagi nal carcinoma. We studied 23 histologically confirmed cases of in situ and invasive vaginal cancer and 28 community controls. Blood samples were collected from participants and tested for the presence of antibo dies to HPV-16 virus-like particles (VLPs), HSV-2, and C. trachomatis. Subjects positive for HPV-16 VLP antibodies were at a 3.5-fold increa sed risk of vaginal neoplasia (95% CI: 0.97-13) and those with high an tibody levels were at a 33-fold increased risk of disease (95% CI: 2.5 -430). Positivity to HSV-2 antibodies was associated with a 3.0-fold i ncreased risk of disease (95% CI: 0.62-15). Similarly, women who teste d positive for C. trachomatis antibodies were at a 4.6-fold increased risk of disease (95% CI: 1.2-18), with those having evidence of high a ntibody titers being at a 6.8-fold increased risk of disease (95% CI: 1.1-43). The risk estimate associated with HPV-16 VLP seropositivity w as not affected by adjustment for HSV-2 and C. trachomatis seropositiv ity (RR: 3.4; 95% CI: 0.79-15). In contrast, inclusion of all three ST As in the model resulted in weakening of risks associated with HSV-2 ( RR: 2.1; 95% CI: 0.31-14) and C. trachomatis (RR: 1.7; 95% CI: 0.34-8. 4). Positivity to at least one of the three STAs examined was associat ed with a 2.7-fold increased risk of disease (95% CI: 0.79-9.5) and th ose positive to all three STAs were at a 17-fold increased risk of dis ease (95% CI: 1.3-220), relative to women negative for antibodies agai nst all three STAs. Associations were in general stronger for in Situ than invasive disease. Our results suggest that the STAs are likely to play an important role in the etiology of vaginal tumors, in concorda nce with findings for more commonly occurring cervical and vulvar tumo rs. Larger studies are required to clarify the independent role of STA s in the pathogenesis of vaginal tumors and to examine the joint effec ts of different STAs on the pathogenesis of this disease.