Background : AIM: to utilize a systematic review of preclinical and clinical data to justify the development of a multi-institutional database to monitor the prevalence and incidence of prostate cancer among women undergoing transgender treatment with long-term estrogen treatment.
Methods : METHODS: A systematic review was done of the available preclinical studies of the effect of estrogen on prostate carcinogenesis using the PUBMED database and a search of (“prostate cancer” AND pathogenesis AND estrogen) and using (prostate carcinogenesis AND estrogen). A review of the clinical studies available of prostate cancer among transgender people on long-term estrogen treatment was done using a PUBMED search of ((transsexual OR transgender) AND (prostate AND cancer OR carcinoma)). Both original articles and reviews were included in these systematic reviews.
Results : RESULTS: The preclinical data collected in the review show that estrogen and estrogen receptors are important in the development and progression of prostate cancer. The primary estrogen receptors in prostate cells are ERα and ERβ. ERβ has been more extensively studied and activation of ERβ is generally considered to be antiproliferative. However, studies show that expression of ERβ in established prostate cancer suggests a more virulent subtype, and that ERβ splice variant 2 may be involved in the development of osteogenic metastases. ERα stimulation by estrogen has been shown to induce prostate carcinogenesis. The clinical data show sparse reporting of prostate cancer among transgender persons on estrogen treatment. The largest study, from the Amsterdam Gender Clinic, found an incidence of prostate cancer among orchiectomized male to female people on estrogen of 0.04% (1 patient of 2306, at age 63) with a median of 20 year follow up. However, they note that only 0.2% of their subjects were over 65 years of age and only 13% had at least 30 years of hormone treatment.
Conclusions : CONCLUSION: Preclinical data suggest that transgender people on long term estrogen treatment may be a higher risk for aggressive prostate cancer. At this time there are insufficient rigorously-obtained, prospective, clinical data on the prevalence and incidence of prostate cancer in this population. Therefore, it is proposed to start a multi-institutional, prospective collection of prostate cancer screening results among transgender people on estrogen therapy who are 50 years or older, with yearly PSA testing.