History of sexually transmitted infections (STIs) may be important in the etiology of ovarian cancer — and a new study links certain STIs with increased risk for the disease.
Using data from the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort, researchers investigated whether past STI was associated with an increased risk for epithelial ovarian cancer. The cohort include 791 cases of cancer and 1669 matched controls.
The median age of participants at blood collection was 56.5 years. Forty percent of participants were seropositive to at least one STI.
“Previous studies have predominantly analyzed ovarian cancer as a single disease, with small sample size precluding analyses by subtype beyond serous vs nonserous disease,” the researchers wrote. “In the current study, we provide a detailed investigation by histotype, observing suggestive heterogeneity by tumor histology.”
Two STIs were associated with an increased risk for epithelial ovarian cancer. First, although Chlamydia trachomatis Pgp3 antibodies were not associated with overall epithelial ovarian cancer risk, they were associated with a higher risk of the mucinous histotype (relative risk [RR], 2.30; 95% CI, 1.22-4.32). Additionally, positive serology for chlamydia heat shock protein 60 was associated with higher risk for epithelial ovarian cancer overall (RR=1.36; 95% CI, 1.13-1.64) and with the serous subtype (RR, 1.44; 95% CI, 1.12-1.85).
The study also revealed that herpes simplex virus-2 was associated with an increased risk for endometrioid epithelial ovarian cancer (RR, 2.35; 95% CI, 1.24-4.43).
No other STIs were associated with an increased risk for epithelial ovarian cancer.
“The results of this study need to be confirmed in other prospective cohorts of sufficient size to investigate STIs and risk by tumor histotype,” the researchers wrote. “Experimental studies delineating the mechanisms linking STIs to [epithelial ovarian cancer], and the primary prevention potential of STI prevention, are tasks for future experimental, translational, and epidemiological research to resolve.”
Idahl A, Le Cornet C, Maldonado SG, et al. Serologic markers of Chlamydia trachomatis and other sexually transmitted infections and subsequent ovarian cancer risk: results from the EPIC cohort [published online April 3, 2020]. Int J Cancer. doi: 10.1002/ijc.32999