Research Shows No Elevated Risk of Gynecological Cancer with Long-Term Testosterone Therapy

A comprehensive study conducted by Amsterdam University Medical Centers has provided reassuring evidence regarding the safety of testosterone use in transmasculine and gender-diverse individuals. The research focused on whether prolonged testosterone therapy, averaging five years, increases the risk of gynecological cancers such as those affecting the uterus, ovaries, vagina, or vulva. Findings indicate that there is no heightened risk of these cancers during the initial years of hormone therapy.

The study tracked 1,955 individuals who identify as transmasculine or gender-diverse and are registered as women at birth. Notably, none of the participants developed gynecological cancers within the study period. Interestingly, some participants showed ongoing activity in the endometrium, and signs of ovulation persisted despite testosterone treatment, highlighting the complexity of hormonal effects.

These results are significant for healthcare providers and individuals considering or already undergoing testosterone therapy. They suggest that early-phase hormone therapy does not contribute to increased cancer risk, offering reassurance for many. Moreover, the study underscores the importance of continued gynecological and contraceptive care, as pregnancy remains possible even during testosterone use.

The research also aligns with recent legislative changes in the Netherlands, where gender registration laws were relaxed, allowing more transmasculine and gender-diverse people to initiate hormone therapy without immediate surgical interventions. While long-term effects remain to be fully understood, these findings provide a basis for better-informed choices and cautious monitoring.

According to co-researcher Wouter van Vugt, ongoing surveillance is crucial to optimize care and ensure safety as more individuals access hormone therapy. The study emphasizes the importance of personalized healthcare approaches to support the well-being of trans and gender-diverse populations.

For additional information, the full study titled "Incidence of Gynaecological (Pre-)Malignancies and Endometrial Activity in Transmasculine and Gender Diverse Individuals Using Testosterone" was published in eClinicalMedicine in 2025. source