Transgender individuals have a gender identity that is different from their birth sex (male, female). Some transgender individuals take hormones or undergo gender confirmation surgery so that their outward gender expression matches their internal gender identity. Cancer risk is an understudied topic in transgender health though they may be at higher risk for cancers related to infectious diseases and certain behaviours. For example, transgender individuals may be at higher risk for HIV, hepatitis B virus (HBV), and human papillomavirus (HPV) due to riskier sexual behaviours or commercial sex work. Some transgender individuals are also at risk for infection with hepatitis C virus (HCV) due to injecting recreational drugs, silicone, or hormones. The use of alcohol and tobacco may also be higher among transgender individuals than cisgender individuals. In addition, transgender persons who keep their natal sex organs (e.g. uterus or testes) are still at risk for reproductive cancers and the risk related to long term use of high dose oestrogens or testosterone for gender transitions is currently unknown. We plan to use anonymised electronic medical records from the CPRD Gold and Aurum databases to estimate the number of transgender patients with these risk factors, cancer screening adherence, and their chance of developing cancer compared to cisgender patients. This study will inform patient clinical care, cancer prevention, and screening guidelines.
Transgender is the catchall term for individuals whose gender expression (masculine, feminine, other) differs from their birth sex (male, female). Gender dysphoria refers due to an individuals discomfort with the incongruence between their experienced gender identity and assigned sex at birth. Some transgender individuals take hormones or undergo gender confirmation surgery so that their outward gender expression matches their internal gender identity. In the UK, approximately 21 in 100,000 persons over the age of 15 are transgender.
Cancer risk is an understudied topic in transgender health due to paucity of available data. Until recently, research on cancer in this population has been limited to a few case reports. Two previous studies have used US cancer registry data to examine cancer distribution by primary site in the US transgender population. Both studies found a higher proportion of certain cancers in this population compared to cisgender individuals, including virally-related and AIDS-defined malignancies. However, these studies were not able to estimate cancer rates or identify risk factors in the transgender population due to lack of denominator data.
There is an urgent need to expand our knowledge of cancer risk among transgender individuals as the population grows and ages. This study will quantify cancer risk among transgender persons, an understudied population with an increased burden of cancer risk factors. We will use the CPRD to identify a cohort of transgender patients with diagnostic codes for gender dysphoria and match them to a cohort of cisgender patients. Our analyses will quantify overall and site-specific cancer risk among transgender patients and will identify risk factors for the development of these cancers. Analyses will be adjusted for common cancer risk factors (smoking history, BMI, and alcohol use). This information can help inform screening guidelines and prevention efforts, which will become increasingly important as the population ages.
The primary outcome of interest is all cancers combined and cancers by anatomic sites; the secondary outcomes of interest are to estimate the prevalence of cancer risk factors (obesity, smoking, problem drinking, diabetes mellitus, cirrhosis, HIV, hepatitis virus infection, and hormonal mediations) in the population. The tertiary outcome of interest is all-cause and cancer-specific mortality. Finally, we would like to assess adherence to recommended cancer screenings and compare outcomes for cervical, colon, and endometrial screenings between transgender and cisgender patients.
Meredith Shiels - Chief Investigator - National Cancer Institute ( NCI )
Sarah Jackson - Corresponding Applicant - National Cancer Institute ( NCI )
Alison Berner - Collaborator - Tavistock and Portman NHS Foundation Trust
Britton Trabert - Collaborator - National Cancer Institute ( NCI )
Duncan Shrewsbury - Collaborator - Brighton and Sussex Medical School
Jalen Brown - Collaborator - National Cancer Institute ( NCI )
Ruth Pfeiffer - Collaborator - National Cancer Institute ( NCI )
Shahinaz Gadalla - Collaborator - National Cancer Institute ( NCI )
Stewart O’Callaghan - Collaborator - Live Through This
HES Admitted Patient Care;HES Outpatient;ONS Death Registration Data;Practice Level Index of Multiple Deprivation