Chapter 18: Screening for Cancer and Cardiovascular

INTRODUCTION

Heart disease and cancer are the two leading causes of death in the general population in the United States,¹ but their impact on transgender and gender diverse (TGD) people is poorly understood. Gender-affirming hormone therapy (GAHT) can play a role in the development of certain cancers, and may worsen some risk factors for cardiovascular disease. Societal and health care sector marginalization of TGD people—via economic disenfranchisement, increased risky behavior, decreased access to care, decreased patient willingness to seek care, and increased stigma—can contribute to higher oncologic and cardiovascular risk as well. This chapter will review what we know about cancer and cardiovascular disease epidemiology in TGD people as well as how to approach screening for these diseases in a primary care setting.

CANCER IN TRANSGENDER AND GENDER DIVERSE ADULTS

Epidemiology

Cancer rates and risks for TGD people remain unclear, even though research on this population has grown exponentially in the past decade.² There are multiple reasons for this. First, most studies on TGD people focus primarily on other topics such as behavioral health and substance use, sexual health, and sexually transmitted infections. Second, research and health registry methodologies for identifying and classifying TGD people vary, leading to sampling errors and a lack of uniformity in data collection.³ Third, very few large-scale prospective studies of any kind about TGD people exist, and recruitment for these can often be exceedingly difficult.²

Despite these challenges, several TGD population cohort studies have been conducted over the past four decades. The earliest of these started in the Netherlands in 1972 with 425 patients (71% AMAB=assigned male sex at birth, 29% AFAB=assigned female sex at birth), more than tripling in size by 2007. In 2011, Djhene and colleagues published a retrospective cohort study assessing cancer mortality of 324 Swedish transgender people (59% AMAB, 41% AFAB) between 1973 and 2003. Two different cohorts from Ghent University Hospital in Belgium have been studied; the earlier cohort consisted of 100 transgender people (50% AMAB, 50% AFAB), while the later cohort looked at 352 individuals (61% AMAB, 39% AFAB). All of these European studies had too small a sample size, not statistical power, and too few incident cases to be effective at analyzing links between certain malignancies and gender dysphoria, its treatments, or a person’s transgender status.²

In the United States, Brown and colleagues have recently studied a cohort of 5135 transgender patients—over half of whom had been prescribed GAHT—within the Veterans Affairs system. Cancer mortality was only one of several variables studied, and cohort members’ gender identities were not accurately categorized, leading to results that were difficult to interpret.² In 2017, Silverberg and colleagues looked at cancer risk among a cohort of 4889 transgender people (57% AMAB, 43% AFAB) from three large regional subsidiaries within the Kaiser Permanente (a large non-for-profit ...