Trabert B, et al. - Researchers used a staged approach in two independent populations to assess the association of serologic markers of Chlamydia trachomatis and other infectious agents with incident ovarian cancer. Findings demonstrated a link between pelvic inflammatory disease and ovarian cancer. A doubling in ovarian cancer risk was observed in relation to the presence of antibodies against prior/current C. trachomatis (Pgp3) in two independent populations; markers of other infectious agents were unrelated.

Methods

• Researchers performed this investigation, including a case–control study in Poland (244 ovarian cancers/556 control subjects) and a prospective nested case–control study in the PLCO Cancer Screening Trial (160 ovarian cancers/159 control subjects).
• They used multivariable adjusted logistic regression to estimate the associations of serologic marker levels with ovarian cancer risk at diagnostic as well as higher thresholds, identified in Poland and independently assessed in PLCO.

Results

• In the Polish study, they found increased ovarian cancer risk (adjusted odds ratio [OR]=1.63, 95% confidence interval [CI] = 1.20 to 2.22) related to antibodies (based on laboratory cut-point) against the chlamydia plasmid-encoded Pgp3 protein (serological gold standard); they noted that ovarian cancer risk increased when a positive result was redefined at higher levels (cut-point 2: OR = 2.00, 95% CI=1.38 to 2.89; cut-point 3 [max OR]: OR=2.19, 95% CI=1.29 to 3.73).
• In the prospective PLCO study, data showed an association of Pgp3 antibodies with elevated risk at the laboratory cut-point (OR = 1.43, 95% CI = 0.78 to 2.63) and more stringent cut-points (cut-point 2: OR=2.25, 95% CI=1.07 to 4.71; cut-point 3: OR=2.53, 95% CI=0.63 to 10.08).
• Findings revealed no association between antibodies against other infectious agents and risk in both studies.