Among the health issues faced by transgender people, cancer has received little scientific attention. Until very recently, no long-term health-tracking studies have focused specifically on cancer in transgender individuals, and the few that are now under way will require years, even decades, to yield useful information.

One focus of these studies will be whether hormones taken to transition from one sex to another could increase the risk for certain cancers—breast cancer in transgender women, for example. There is reason to think that they may, but without hard scientific data, the extent of that risk is impossible to pin down. A recently launched $5.7 million, five-year investigation, led by the National Institutes of Health, will track the health of young transgender people over the course of their lifetimes to monitor the effect of hormones on cancer risk, among other health concerns.

Regardless of risk, research has pointed to several factors that might inhibit transgender people from seeking or receiving  timely cancer care. One of these is fear of discrimination. Nearly a quarter of those who participated in the 2015 U.S. Transgender Survey, for example, reported that they did not see a doctor when they needed to because of fear of being mistreated as a transgender person. One-third of the respondents who had seen a health care provider in the previous year reported having at least one negative experience related to being transgender, such as being refused treatment, verbally harassed, or having to teach the provider about transgender people in order to get appropriate care. The survey, which gathered data from 28,000 respondents, is conducted by the National Center for Transgender Equality (NCTE).

“As The Lancet Oncology has pointed out, it may be psychologically difficult for transgender patients to address health concerns associated with reproductive organs retained after transition to current gender,” said Daniel Morganstern, MD, a specialist in breast cancer and cancer genetics and prevention at Dana-Farber, who is one of many Institute physicians and staff with a special interest in treating and caring for LGBTQ patients. “To provide care that is both compassionate and comprehensive, health care providers need to be cognizant of these factors as well the barriers that exist to accessing care.”

A lack of awareness about their unique health needs can also deter transgender people from being screened for certain cancers. Transgender men and women remain susceptible to cancers of reproductive organs that no longer match their gender identity, a 2015 editorial in The Lancet Oncology noted. People who undergo sex-reassignment surgery retain a small amount of tissue from their original reproductive organs. A trans woman, therefore, may be at risk for prostate cancer, while a trans man may retain a risk for ovarian cancer. But not all transgender people are adequately informed about these risks, potentially leading them to neglect standard screening tests.

Compounding the problem, some health insurance plans don’t cover cancer screenings that don’t match an individual’s current gender identity, Newsweek magazine reported last year. Under such plans, a trans man, for example, may not be covered for a mammogram, although the situation is beginning to improve.

Another factor, according to The Lancet, is that transgender people are more likely than the general population to smoke cigarettes and drink alcohol, and have a greater chance of contracting HIV and the human papillomavirusall associated with greater risk for certain cancers. Transgender individuals also are more likely not to have health insurance, decreasing their access to effective health care, the NCTE has found.

This article was originally published on the Dana Farber Cancer Institute website.