Summary

This review gathered 39 studies on breast removal surgery for young people with gender distress and rated how trustworthy the evidence was. Nearly all only followed operated patients, with no comparison group. Only short-term surgical complications were rated high-quality evidence, and they were uncommon: no deaths, about 2% to 3% loss of the nipple or skin graft through tissue death, and about 5% thick scarring. For the results that matter most, such as gender distress, mental health, suicide attempts, quality of life and regret, the evidence was weak or very weak. One study did suggest people were about half as likely to self-harm after surgery. The authors call for better studies. The review shows the evidence is weak; it does not show that surgery fails to help. It was funded by SEGM, a group that urges caution, and surgeons have challenged its framing in published letters.

Key findings

• 该综述检索到2023年6月，找到39项研究：只有3项比较了不同组，2项测量了人们手术前后的变化；其余34项只描述了接受手术的患者。
• 高质量的证据只来自关于手术并发症的研究：没有死亡（5项研究），每1,000人中约20人因组织坏死而损失乳头或皮肤移植（13项研究），每1,000人中约10人损失皮瓣（3项研究），每1,000人中约50人出现厚重瘢痕（12项研究）。
• 两项比较手术与束胸的研究，对于胸部相关的性别痛苦以及对身体和胸部的满意度，给出了非常薄弱的证据。
• 一项比较手术与不手术的研究，对于痛苦和自杀未遂给出了非常薄弱的证据，并有薄弱证据表明手术后人们自伤（无自杀意图）的可能性约减少一半。
• 生活质量、抑郁、死于自杀、胸部满意度和后悔均被评为证据非常薄弱，主要是因为没有对照组。
• 原计划检查结果是否因其他心理健康状况、痛苦开始的年龄或性取向而不同，但无法完成；自杀想法、性功能和后续手术也未评估。
• 作者呼吁开展向前追踪患者的研究，并在符合伦理的情况下开展随机试验，为患者、外科医生、指南撰写者和政策制定者提供依据。

Abstract

BACKGROUND: Gender dysphoria (GD) refers to psychological distress associated with the incongruence between one's sex and one's gender. In response to GD, birth-registered female patients may choose to undergo mastectomy. In this systematic review, the authors summarize and assess the certainty of the evidence about the effects of mastectomy. METHODS: We searched MEDLINE, Embase, PsycINFO, Social Sciences Abstracts, LGBTQ+ Source, and Sociological Abstracts through June 20, 2023. We included studies comparing mastectomy to no mastectomy in birth-registered patients younger than 26 years with GD. Outcomes of interest included psychological and psychiatric outcomes, and physical complications. Pairs of reviewers independently screened articles, abstracted data, and assessed risk of bias of the included studies. We performed meta-analysis and assessed the certainty of the evidence using the Grading of Recommendations Assessment, Development, and Evaluation approach. RESULTS: We included 39 studies. Observational studies (n = 2) comparing mastectomy to chest binding provided very low-certainty evidence for the outcome of GD. One observational study comparing mastectomy to no mastectomy provided very low-certainty evidence for the outcomes of global functioning and suicide attempts, and low-certainty evidence for the outcome nonsuicidal self-injury (adjusted OR, 0.47; 95% CI, 0.22 to 0.97). Before-and-after (n = 2) studies provided very low-certainty evidence for all outcomes. Evidence from case series (n = 34) studies ranged from high to very low certainty. CONCLUSIONS: Case series studies demonstrated high-certainty evidence for the outcomes of death, necrosis, and excessive scarring; however, these are limited in methodologic quality. In comparative and before-and-after studies, the evidence ranged from low to very low certainty.

Conclusion

The best available evidence reporting the effects of mastectomy in individuals with GD ranged from high to very low certainty. High certainty evidence in this SR was derived from case series studies only. High-certainty evidence from prospective cohort studies and, if ethical, randomized controlled trials, are needed to describe the short- and long-term effects of mastectomy in individuals with GD on mental health outcomes. Higher certainty evidence would be useful to individuals with GD considering chest masculinization; clinicians and surgeons involved in their care; guideline developers; and policy makers and stakeholders who make decisions about treatment related to GD.