E87: Breast Cancer and Hormone Therapy in Transgender Patients: A Review of Case and Cohort Studies

ePoster Abstract Author(s)

Anthony Baez, MD

Breast Surgery Fellow
NYU Grossman School of Medicine
Long Island City, New York, United States

Submitter(s)

Anthony Baez, MD

Breast Surgery Fellow
NYU Grossman School of Medicine
Long Island City, New York, United States

Author(s)

Anthony Baez, MD

Breast Surgery Fellow
NYU Grossman School of Medicine
Long Island City, New York, United States
ZO

Zeynep Ozdemir, MD

Resident Physician
Istanbul University Cerrahpasa - Cerrahpasa School of Medicine, United States
TA

Thomas Amburn, MD

Resident Physician
NYU Grossman School of Medicine, United States
AM

Alyssa Marmer, BA

Research Associate
NYU Langone Health, United States
LA

Likolani Arthurs, MD

Resident Physician
NYU Grossman School of Medicine, United States
AG

Amber Guth, MD

Breast Fellowship Program Director
NYU Grossman School of Medicine, United States
FS

Freya Schnabel, MD

Director of Breast Surgery
NYU Grossman School of Medicine, United States

Introduction: 1.03% (1 in 97 individuals) of the United States population identifies as transgender. Many of these individuals seek gender affirming medical and surgical treatments. Gender affirming hormone therapy (GAHT) poses a unique challenge in the management of breast cancer in these patients, particularly those who may benefit from tumor endocrine therapy (ET). Our objective is to review the literature related to the management of GAHT and ET in transgender patients with breast cancer.

Methods: We conducted a systematic literature search using PRISMA guidelines through PUBMED, GOOGLE SCHOLAR and MEDLINE for articles published between 1/1/2003 and 10/1/2023. We identified 3 cohort studies and 34 case reports. The main endpoints considered were the use of GAHT, tumor hormone receptors (HR) and the use of ET.

Results:
A total of 49 patients (17 MtF, 32 FtM) were included in our analysis. The mean age at cancer diagnosis was 40.5 and 54.7 years in the FtM and MtF groups respectively. In the FtM group, 18 (56.3%) tumors were invasive ductal carcinoma (IDC), 7 (21.8%) DCIS , 4 (12.5%) unspecified invasive carcinomas and 3 (9.4%) other subtypes. In the MtF group, 12 (70.6%) tumors were IDC, 2 (11.7%) DCIS, 2 (11.7%) unspecified invasive carcinomas and 1 (7.1%) secretory carcinoma. Amongst tumors tested in the FtM group, 26/31 (83.8%) were estrogen receptor (ER) positive and 20/30 (66.6%) were progesterone receptor (PR) positive. In the FtM group, 11/17 (64.7%) were ER+ and 9/17 (52.9%) were PR+.

Prior to cancer diagnosis, 24 FtM patients (75%) received testosterone-based GAHT for a mean period of 6.7 years. GAHT after cancer diagnosis was recorded in 16 FtM cases: 8 patients (50%) continued, 7 (43.4%) discontinued and 1 patient initially discontinued and later resumed. All MtF patients received estrogen-based GAHT for a mean duration of 20.2 years. GAHT after diagnosis was recorded in 10 MtF cases: 9 patients (90%) discontinued and 1 patient continued. ET use was recorded in 20 FtM patients with HR+ tumors: 15 initiated ET (75%), 4 (20%) did not and 1 patient initiated but discontinued due to side effects. ET was recorded in 8 FtM patients with HR+ tumors: 6 (75%) patients initiated ET and 2 (25%) did not.

Conclusions: Breast cancer care for transgender patients requires a personalized approach given the heterogeneity of GAHT, tumor biology and patient preferences. This study demonstrates variable clinical practices pertaining to GAHT and ET which may be attributed to opposing patient-physician interests. It is therefore important to consider the gender identity needs of these patients when formulating cancer treatment plans.

Learning Objectives:
Describe the management of gender affirming hormone therapy in transgender individuals diagnosed with breast cancer according to previous case reports and cohort studies.
Describe the use of tumor endocrine therapy in transgender individuals diagnosed with hormone sensitive breast cancers according to previous case reports and cohort studies.
Describe the proportion of breast cancer subtypes and tumor biomarkers in transgender individuals according to previous case reports and cohort studies.