Breast imaging of transgender patients and breast cancer prevalence

Transgender patients have both special and similar needs as non-transgender individuals with respect to breast cancer screening. They also pose special considerations for radiologists, as evidence-based guidelines do not exist and data is lacking. Radiologists at the Icahn School of Medicine at Mount Sinai in New York City summarized published data and made recommendations in the January 2018 issue of Current Radiology Reports.

Evidence-based guidelines for breast cancer screening do not yet exist for the transgender population. In their article, lead author Emily B. Sonnenblick, MD, associate professor of radiology at Icahn, and her colleagues recommend screening mammography for all transgender women who have received hormone treatment for 5 years or longer and who have known risk factors for breast cancer, as well as for all transgender men (female-to-male) who have not had surgical breast removal.

The authors also recommend that radiology departments and imaging centers modify their intake forms to allow patients to identify themselves as transgender, to note their preferred gender, and to make it easy to provide hormonal and surgical history relevant to radiological interpretation. Technologists and staff should also be trained in cultural sensitivity.

Additional recommendations from the group include:

• Applying standard protocols for diagnostic mammography, breast ultrasound, and breast magnetic resonance imaging (MRI) examinations to symptomatic transgender women who receive cross-hormone therapy, as the same breast pathology occurs.
• Evaluating palpable abnormalities in patients who have not undergone breast augmentation with mammography and ultrasound. Patients over 30 with unilateral clear or bloody nipple discharge should have a mammogram followed by ultrasound, whereas younger patients should have an initial ultrasound exam.
• Imaging patients with breast implants with standard oblique, craniocaudal, and Eklund displaced views.

The authors also recommend that radiologists be alert to the possibility that some patients may have had free silicone injection, a practice that is illegal in the United States. Optimal imaging for these patients has yet to be established. Free-particle injections present as numerous diffuse round and irregular high-density masses. Large fibrotic masses in the retroglandular fat and pectoralis muscle caused by free silicone may obscure breast tissue and mimic malignancy. Fibrotic granulomas on breast MRI are non-enhancing circumscribed T2 high signal with absent signal on T1-weighted fat-suppressed images, the authors write.

The authors also recommend that all transgender patients receive a detailed genetic risk assessment based on family history of breast, ovarian, prostate, and/or pancreatic cancer and ancestry prior to hormone treatment.

The impact of hormone treatment on breast cancer risk is unknown. The most recent data on the prevalence and characteristics of breast cancer in transgender patients was presented in March at ENDO 2018, the annual meeting of the Endocrine Society in Chicago.¹ Researchers from Amsterdam reported that the number of breast cancer cases in transgender individuals of both sexes was lower than they statistically predicted. Specifically, 25 breast cancer cases in a population of 2,571 during a follow-up period of 22,678 person-years. Six cases were identified in transgender men in a population of 1,324 followed for 10,102 person years. Presenter Christel Josefa Maria de Blok, MD, of the Department of Endocrinology and Center of Expertise on Gender Dysphoria of the VU University Medical Center, said the researchers had expected 32 and 10 cases respectively.

Patients were diagnosed at a median age of 51 years in transgender women and 46 years in transgender men. For both, the most prevalent type of breast cancer was a ductal carcinoma (60% in women and 83% in men). In transgender women, 83% of the tumors was estrogen receptor positive (ER+), 61% progesterone receptor positive (PR+), and 6% human epidermal growth factor receptor-2 (HER2/neu) positive. For transgender men, the rates were 60% ER+, 60% PR+, and 40% HER2/neu positive. A total of nine women and two men had developed metastases.

The data for this study was collected from a national database (PALGA) which has been registering histopathology and cytopathology in the Netherlands since 1971. The search included all relevant patient data from 1971 through August 2017.

Data collection to assess optimal imaging and the role of mammography screening of transgender individuals is needed, Dr. Sonnenblick said. Mount Sinai’s Dublin Breast Center is conducting an open, ongoing prospective study called the Transgender Imaging Registry (TransFIR) to gather data about biopsy rates and cancer detection in transgender patients who have breast imaging. It may be accessed at https://transfir.org.

REFERENCES

1. de Blok CJM, Wiepje C, Nota NM, et al. OR25-6 - Breast cancer in transgender persons receiving cross-sex hormone treatment: Results of a nationwide cohort study. ENDO 2018 program. Accessed from http://www.abstractsonline.com/pp8/#!/4482/presentation/8190 on May 29, 2018.
2. Sonnenblick EB, Shah AD, Goldstein Z, et al. Breast imaging of transgender individuals: A review. Curr Radiol Rep. 2018 6:1 doi.org/10.1007/s40134-018-0260-1.