Cancer Screening in Transgender Individuals

Cancer is the leading cause of death in almost every country worldwide, with wide-ranging societal and economic repercussions. Cancer screening, aimed at early detection and prevention, targets a unique window of opportunity that offers the patient the best possible clinical outcome.

Screening refers to the detection

Screening refers to the detection of premalignant or early disease in asymptomatic people by means of physical examinations, laboratory and radiological investigations, or other tests.2 To ensure a balance between cost-effectiveness and yield, screening studies should target diseases with high prevalence in the population being screened. The greatest impact factor results from early detection and treatment of diseases that would otherwise result in high societal and medical costs with delayed diagnosis.

However, screening tests are a double-edged sword. Screening may result in false-positive results that may subsequently lead to patient anxiety and additional interventions, such as radiation exposure or invasive procedures. Over-screening can lead to overtreatment of diseases that may not otherwise have caused the patient harm. On the other hand, under- screening may also delay disease detection and treatment.3 For this reason, clinical judgment and decision-making are critical in evaluating each individual patient’s risk profile.

Transgender individuals represent a unique population when it comes to screening. Their unique lifestyles-such as prolonged use of cross-sex hormone therapy to achieve the desired secondary sexual characteristics, gender reassignment surgery, or specific social behaviors – can influence the incidence of specific cancers. As a result, cancer screening in transgender individuals must take these factors into account when compared to the protocol used in cisgender individuals.

Cancer screening theory

Cancer screening in the trans population can be categorized into two types:

Cancer screening in transgender individuals with the same protocol as cisgender individuals

Some cancers have equal incidence in cisgender and transgender individuals. It stands to reason therefore that the screening criteria for cisgender and transgender individuals are identical for these diseases, which include colorectal cancers, hepatobiliary cancers, and lung cancer. The screening criteria for these diseases are beyond the scope of this chapter.

Cancer screening protocols specific to transgender individuals

In natal females, the use of hormone replacement therapy increases the risk of cancer in sex hormone-responsive organs, such as breast (responding to estrogen and progesterone)4 and uterus (responding to estrogen). However, the relative risk to transgender individuals is unclear due to a dearth of studies on this topic. The most-reported studies available are on breast cancer, likely due to its high incidence and the fact that it is likely related to feminizing hormone therapy. Breast cancer incidence among transgender individuals, especially in male-to-female patients, is not as high as in natal females but is higher than the incidence of breast cancer in natal males.

Theoretically, the use of cross-sex hormones in transgender individuals can increase malignancy risk in other organs, examples being cervical and ovarian cancer. On the other hand, cross-sex hormones may be protective in some instances. It may lower the incidence of prostate cancer in male-to-female transgender women, as evidenced by the fact that prostate cancer in this subset of patients are mostly reported in those who started feminizing hormones after the age of 50.

In addition, gender reassignment surgery can affect the incidence of certain cancers.

• In male-to-female transgender individuals: Orchiectomy can prevent testicular cancer and reduce prostate cancer risk. Penectomy decreases the risk of penile cancer.
• In female-to-male transgender individuals: Hysterectomy prevents cervical and endometrial cancers. Bilateral oophorectomy prevents ovarian cancer and may reduce the risk of breast cancer. Male chest wall contouring surgery (bilateral total mastectomy, skin-sparing mastectomy, or nipple-sparing mastectomy) significantly reduces – but does not eliminate – breast cancer risk.

Awareness and compliance with routine cancer screening is lower in the transgender population compared to that in cisgender groups. However, that is not the only reason trans men and women may be at higher risk for certain types of cancers. Socially-related risk factors including substance use, smoking, drinking, and obesity may all increase the risk for certain cancer types. Human papillomavirus (HPV) infection, which is commonly associated with Human Immunodeficiency Virus (HIV), can cause rectal neovaginal cancers in male- to-female transgender individuals (especially in those who underwent penile skin inversion vaginoplasty). HPV also increases the risk of cervical cancer and vaginal cancer in female- to-male transgender individuals.

Refer: Cancer Screening in Transgender Individuals, The Thai Handbook of Transgender Healthcare Services, Center of Excellence in Transgender Health, Chulalongkorn University