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荷兰队列研究发现：使用激素的跨性别女性乳腺癌风险是男性的46倍——但仍低于女性

接受激素治疗的跨性别者的乳腺癌风险：荷兰全国队列研究

队列与登记研究跨性别激素
Authors
Christel J.M. de Blok, Chantal M. Wiepjes, Nienke M. Nota, Klaartje van Engelen, Muriel A. Adank, Koen M.A. Dreijerink, Ellis Barbé, Inge R.H.M. Konings, Martin den Heijer
Journal
BMJ
Year
2019
Source
https://doi.org/10.1136/bmj.l1652

Summary

Researchers used records from the Amsterdam gender clinic, which treats over 95% of Dutch transgender patients, linked to the national record of cancer diagnoses. They counted breast cancers in about 3,500 people on cross-sex hormones. Trans women got breast cancer far more often than men normally do (about 46 times), but still less often than women. Their tumours looked like the typical hormone-sensitive breast cancers seen in women. This suggests estrogen, and possibly the testosterone-blocking drug cyproterone acetate, shifts risk toward the female pattern. Trans men had a lower risk than women, likely helped by having had their breasts removed. The authors concluded the overall risk is low and normal screening is enough. With only 15 and 4 cases, missing data on major risk factors, and comparisons with the general population, the numbers are rough.

Key findings

  • 该研究追踪了2,260名跨性别女性和1,229名跨性别男性的激素治疗，随访总计约34,000和15,000年。
  • 跨性别女性在使用激素典型的18年后（范围7至37年）出现了15例乳腺癌，通常在50岁时。
  • 乳腺癌在跨性别女性中的常见程度约为男性的46倍（可能在27倍到75倍之间），但只有女性的约三分之一。
  • 跨性别女性的大多数肿瘤是激素敏感型（83%由雌激素驱动，67%由孕酮驱动），与女性中通常所见的相似。
  • 跨性别男性有4例乳腺癌，约为女性比率的五分之一，但为男性比率的59倍；其中三例发生在乳房切除数年之后。
  • 研究人员无法比较不同的激素药物，因为治疗经常变化，而且大多数跨性别女性服用的是醋酸环丙孕酮。
  • 作者得出结论认为，对于使用激素的跨性别者，正常的乳腺筛查规则已经足够。

Abstract

OBJECTIVE: To investigate the incidence and characteristics of breast cancer in transgender people in the Netherlands compared with the general Dutch population. DESIGN: Retrospective, nationwide cohort study. SETTING: Specialised tertiary gender clinic in Amsterdam, the Netherlands. PARTICIPANTS: 2260 adult trans women (male sex assigned at birth, female gender identity) and 1229 adult trans men (female sex assigned at birth, male gender identity) who received gender affirming hormone treatment. MAIN OUTCOME MEASURES: Incidence and characteristics (eg, histology, hormone receptor status) of breast cancer in transgender people. RESULTS: The total person time in this cohort was 33 991 years for trans women and 14 883 years for trans men. In the 2260 trans women in the cohort, 15 cases of invasive breast cancer were identified (median duration of hormone treatment 18 years, range 7-37 years). This was 46-fold higher than in cisgender men (standardised incidence ratio 46.7, 95% confidence interval 27.2 to 75.4) but lower than in cisgender women (0.3, 0.2 to 0.4). Most tumours were of ductal origin and oestrogen and progesterone receptor positive, and 8.3% were human epidermal growth factor 2 (HER2) positive. In 1229 trans men, four cases of invasive breast cancer were identified (median duration of hormone treatment 15 years, range 2-17 years). This was lower than expected compared with cisgender women (standardised incidence ratio 0.2, 95% confidence interval 0.1 to 0.5). CONCLUSIONS: This study showed an increased risk of breast cancer in trans women compared with cisgender men, and a lower risk in trans men compared with cisgender women. In trans women, the risk of breast cancer increased during a relatively short duration of hormone treatment and the characteristics of the breast cancer resembled a more female pattern. These results suggest that breast cancer screening guidelines for cisgender people are sufficient for transgender people using hormone treatment.

Conclusion

This large nationwide cohort study in the Netherlands showed an increased risk of breast cancer in trans women compared with cisgender men. The risk in trans women is still lower than in Dutch cisgender women and resembles a more female type of breast cancer and hormone receptor status. In trans men, a lower risk compared with Dutch cisgender women was observed. Based on this study, we conclude that the absolute overall risk of breast cancer in transgender people remains low and therefore it seems sufficient for transgender people using hormone treatment to follow screening guidelines as for cisgender people. As the risk of breast cancer in trans women increased during a relatively short duration of hormone treatment, it would be worthwhile for future studies to investigate in more detail the cause of breast cancer in transgender people receiving hormone treatment.