Fidler-Benaoudia, Miranda MBobawsky, Kirsten MQureshi, Hina M2023-05-112022-11-22Qureshi, H. M. (2022). Investigating the Risk of Primary Invasive Cancer Among Individuals With a History of Bacterial Sexually Transmitted Infections: A Population-Based Study in Alberta, Canada (Master thesis). University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca .http://hdl.handle.net/1880/116344Background: The number of new cancer cases is rising in Canada. Incidence rates of chlamydia, gonorrhea, and syphilis have also increased over the last two decades. However, few studies have explored the relationship between these bacterial sexually transmitted infections (STIs) and cancer risk.Purpose: To investigate the risk of primary invasive cancer among individuals with a prior reported diagnosis of chlamydia, gonorrhea, and/or syphilis in Alberta, Canada, from 2000-2019. Methods: This population-based, data-linkage, retrospective cohort study explored seven exposure categories based on prior records of three bacterial STIs. We investigated outcomes for (a) cancers overall, including all cancer sites, and (b) thirteen individual cancer regions. A cohort comprising 175,024 Albertan residents with a reported diagnosis of chlamydia, gonorrhea, and/or syphilis from January 1, 2000, to December 31, 2019, were identified and followed until the development of invasive cancer or death or study end date, whichever happened first. The cancer incidence rate in the STI cohort was compared with the cancer incidence rate in the general population of Alberta using standardized incidence ratios (SIR) and absolute excess risk (AER) with 95% confidence intervals (CI).Results: We identified 1,593 subsequent first primary invasive cancers and in-situ bladder carcinomas during the 1,385,580 person-years of observation (median follow-up=7.3 years; IQR=3.4-11.9). We did not find increased or decreased risk for cancers overall associated with any of the seven exposure categories. However, an increase in risk was identified for cancers of female genital organs (SIR=1.4, 95%CI=1.2,1.6; AER=0.6, 95%CI=0.3,0.9) and male genital organs (SIR=1.5, 95%CI=1.2,1.8; AER=1.1, 95%CI=0.5,1.8) among those exposed to chlamydia only; cancers of digestive organs in case of exposure to gonorrhea only (both sexes combined: SIR=1.4, 95%CI=1.02,2.0; AER=1.6, 95%CI=0.0,3.2); cancers of respiratory and intrathoracic organs (both sexes combined: SIR=1.7, 95%CI=1.1,2.5; AER=3.8, 95%CI=0.2,7.3), as well as cancers of hematopoietic and reticuloendothelial system (both sexes combined: SIR=1.6, 95%CI=1.02,2.3; AER=3.3, 95%CI=-0.3,6.8) in case of syphilis only exposure; and cancers of female genital organs among those exposed to chlamydia and gonorrhea (SIR=1.9, 95%CI=1.2,3.0; AER=1.2, 95%CI=0.1,2.2). Conclusion: Overall findings of this study suggest a possible role of common bacterial STIs in carcinogenesis.Englishchlamydiagonorrheasyphilissexually transmitted infectionscancerHealth And Environmental Sciencesmaster thesis