Outcomes and Perceptions of Masculinizing Mammoplasty Among Transgender Men in Brazil

Abstract

Background

Transgender men often experience body image dissatisfaction because of incongruence between their gender identity and physical appearance. Masculinizing mammoplasty (MM) aligns physical appearance with gender identity; however, its impact on body image satisfaction in Brazil has not been comprehensively assessed using validated tools.

Objectives

To evaluate satisfaction with chest appearance, nipple aesthetics, and body investment among transgender men in Brazil, comparing those who have undergone MM with those who have not, using validated tools, such as the BODY-Q Chest, BODY-Q Nipple, and Body Investment Scale.

Methods

This cross-sectional study included 90 transgender men aged ≥18 years recruited between June and September 2024. Participants were allocated to 2 groups: those who had undergone MM (n = 45) and those eligible but had not yet undergone surgery (n = 45). Inverse probability of treatment weighting and regression models adjusted for age, BMI, and education level were used.

Results

Participants had a mean age of 32.2 years (standard deviation [SD] ±8.1, range, 19-62) and BMI of 27.9 kg/m² (SD ±4.8). The MM group had a mean time since surgery of 40 months (SD ±29.2). After adjustment, MM was associated with significantly greater satisfaction with chest appearance (average treatment effect [ATE], 60.98; 95% CI, 53.02-68.93), nipple aesthetics (ATE, 50.61; 95% CI, 38.99-62.23), and body investment (ATE, 11.02; 95% CI, 5.66-16.38). Chest binding was significantly reduced in the MM group (P < .001).

Conclusions

Transgender men in Brazil who underwent MM reported higher body image satisfaction and quality of life, supporting the role of this procedure in enhancing mental health.

Level of Evidence: 3 (Therapeutic)

Gender identity refers to an individual's internal perception of being male, female, or neither, which may diverge from the sex assigned at birth, often leading to gender dysphoria (ie, significant psychological distress stemming from the mismatch between gender identity and physical appearance). This incongruence, which can manifest as social or physical discomfort, frequently prompts transgender individuals to pursue body modification procedures (BMPs), such as masculinizing mammoplasty (MM) to align their physical appearance with their gender identity.^1-3 MM is a prevalent surgical procedure among transgender men to achieve a more masculine chest contour.⁴ However, despite the increasing demand, the impact of MM on body image satisfaction in Brazil has not been comprehensively evaluated using validated instruments.

Approximately, 0.1% to 2% of the population experience gender dysphoria, although not all gender-diverse individuals experience it.^5,6 Estimating the prevalence of transgender identities is challenging because studies often focus on individuals seeking transition-related care.⁷ In Brazil, 0.69% of adults self-identifies as transgender, whereas 1.19% self-identify as nonbinary, which is consistent with previous research.^3,8 Globally, 3664 transgender individuals were murdered between 2008 and 2020, with Brazil leading these statistics and registering at least 1 daily murder in recent decades, particularly among transgender women.^9,10

The increasing demand for BMPs driven by legislative changes in the United States between 2016 and 2020 emphasizes the growing need for such surgeries.^7,11 In Brazil, policies introduced in 2011 and expanded in 2013 have similarly improved access to these procedures through the public health system (Sistema Único de Saúde).^12,13 There is a significant lack of data from low- and middle-income countries (LMICs), particularly regarding the healthcare needs of transgender men. Most studies on BMPs have focused on transgender women, leaving a substantial gap in our understanding of the unique health challenges faced by transgender men. This gap is especially notable in Brazil, where healthcare disparities persist, and specific data on transgender men and MM are scarce.¹⁴ Addressing this research gap is important to advancing the healthcare and surgical outcomes for transgender men in LMICs.

Despite the associated health risks, ∼87% of transgender men use chest binders to attain a flatter chest; however, binders are typically no longer needed after surgery.^15,16 MM, also known as “chest reconstruction” or “top surgery,” is one of the most frequently requested procedures among transgender men.^6,17,18

Understanding the differences in patient satisfaction between those who have undergone surgery and those who have not is necessary to guide clinical practice. The use of validated tools to assess postsurgical outcomes offers an unprecedented evaluation of MM in transgender men in Brazil.^8,16,19

BMPs, particularly MM, are a significant component of the transition process for many transgender men and nonbinary individuals assigned to females at birth.^20-23 This procedure is associated with significant improvements in body image, reduced gender dysphoria, and enhanced quality of life.^19,20,24,25 Thus, this study aimed to evaluate satisfaction with chest appearance, nipple aesthetics, and body investment among transgender men in Brazil, comparing those who have undergone MM with those who have not.

METHODS

Study Design

This single-center, observational, cross-sectional, controlled study was approved by the ethics committee of the Federal University of São Paulo (Unifesp) (registration number 6.895.053) and registered with the Brazilian Registry of Clinical Trials (ReBEC) under the registration code RBR-7jmc5yw. This study followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines.²⁶ Written informed consent was obtained from all participants.

Study Participants and Participant Criteria

Between June and September 2024, a consecutive sample of transgender men with gender dysphoria from the Center for Studies, Research, Extension, and Assistance to Transgender People "Professor Roberto Farina" (Núcleo Trans) was invited to participate. The inclusion criteria were transgender men residing in Brazil, aged 18 years or older, with a BMI between 18 and 36 kg/m², who were either eligible for MM but had not undergone the procedure (control group) or had undergone MM at least 3 months earlier (MM group). The exclusion criteria included lack of consent; illiteracy; cognitive, neurological, or physical disabilities that could hinder questionnaire completion; serious, uncontrolled psychiatric illnesses (eg, psychosis); or conditions that could impair the ability to engage with the study measures, such as unrealistic perceptions of body image. Participants with common, well-managed conditions, such as anxiety or depression, including those on medication, were not excluded from the study.

Sampling

The sample size was calculated using G*Power 3.1 software (Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany) based on data from previous studies employing the same scales used in this study.^18,19 The parameters included an effect size (d) = 1.02, α error = 0.05, power (1 − β) = 0.99, and allocation rate N2/N1 = 1, resulting in a minimum sample size of 74. To account for an estimated 20% dropout rate, 90 participants were enrolled, with 45 assigned to each group.

Measures

BODY-Q

This scale, developed in 2013 and published in 2016, measures various aspects of body appearance. In 2018, the “Chest” and “Nipple” scales were translated, validated, and culturally adapted to Brazilian Portuguese. The Chest module comprises 10 subjective chest appearance components and an optional operation scar item, whereas the Nipple module includes 5 nipple evaluation items. Each item is rated on a Likert scale from 1 (very dissatisfied) to 4 (very satisfied). Scores are converted to Rasch-equivalent transformed scores, with higher scores indicating greater satisfaction. The Cronbach's alpha for the Chest scale ranged from 0.95 to 0.98, and that for the Nipple scale ranged from 0.87 to 0.94, indicating good-to-excellent internal consistency.^27,28

Body Investment Scale

The Body Investment Scale (BIS) is a self-administered instrument that assesses personal investment in the body ranging from neglect to self-care or self-harm. Originally developed in English in 1998, it was adapted into a 20-item Portuguese version in 2008.²⁹ Participants rate the frequency of specific behaviors on a Likert scale from 1 (strongly disagree) to 5 (strongly agree). Total scores range from 20 to 100, with higher scores indicating greater body investment. The Cronbach's alpha for the scale ranged from 0.70 to 0.81, indicating acceptable to good internal consistency.

Procedures

Eligible participants completed the Brazilian versions of the BODY-Q Chest and Nipple scales as well as the BIS. Sociodemographic and clinical data were collected using a structured questionnaire administered concurrently with the other instruments. Surgical techniques were documented based on patient reports.

Statistical Analysis

The Kolmogorov–Smirnov test was used to assess the normality of the numerical variables. Demographic variables are presented as means with standard deviations (SDs) for continuous data and as counts with percentages for categorical data. Group comparisons were conducted using t tests for continuous variables and Fisher's exact test or Pearson's χ² test for categorical variables, depending on the distribution of data. The χ² goodness-of-fit test was used to evaluate the categorical variable fit, whereas the binomial test was applied for binary outcomes.

The relationship between the time elapsed since surgery (in months) and the 3 primary outcome measures (BODY-Q Chest, BODY-Q Nipple, and BIS scores) was analyzed using linear regression models to evaluate the effect on each outcome.

Inverse probability of treatment weighting (IPTW) was used to reduce bias and confounding in estimating the treatment effects. IPTW assigns weights to individuals based on the inverse probability that they receive treatment given their covariates (propensity score). This creates a synthetic sample that balances the distribution of covariates between the treated and untreated groups, simulating a randomized experiment. Covariates included age, current life partner status, preoperative chest binding, substance abuse, highest educational level, experience of violence, BMI, use of medications, and name rectification.

Propensity scores were calculated using logistic regression, and weights were applied to adjust the sample. The balance between groups was assessed using standardized mean differences. Treatment effects were estimated using inverse probability weighted regression adjustment (IPWRA), which was further adjusted for covariates while estimating treatment effects, ensuring robustness. The variance inflation factor (VIF) was calculated to assess multicollinearity among the covariates.

The minimal clinically important difference (MCID) was calculated based on the standard error of the estimate and SD from the control group. Statistical significance was set at P < .05. All analyses were conducted using Stata 18 and R.

RESULTS

Among the 90 participants, those who underwent MM reported significantly greater satisfaction with chest appearance, nipple aesthetics, and overall body investment than those who did not undergo surgery (P < .001). The most common racial background was white, with a mean age of 32.2 years (SD ±8.1, range, 19-62 years). The mean BMI was 27.9 kg/m² (SD ±4.8 kg/m²). A significant proportion of the participants (57%) had completed college education. Substance use was common, and although most participants did not report experiencing violence, a substantial number reported experiencing discrimination in the pooled data. Hormone use was also prevalent. For those who underwent surgery, the most common technique was a double incision with a nipple graft (73%). Chest binding was also a common practice (see Table 1 for a comprehensive presentation of demographic and clinical characteristics).

There were no missing data, and adjustments for covariates through IPTW ensured balanced comparisons between groups.

Before IPTW adjustment, significant differences in chest binding and BMI were observed between the groups. After weighing, the balance between groups improved (Table 2). The VIF for all covariates was <1.28, indicating that multicollinearity was not a concern.

Hormone use was initially included as a covariate owing to its expected influence on chest satisfaction. However, it demonstrated perfect collinearity and could make the estimation of the model unstable or unreliable because nearly all participants were receiving hormone therapy. To address this issue and clarify the effects of surgery and other covariates, hormone use was excluded from the final model.

No significant differences in BODY-Q Chest and Nipple or BIS scores were found based on the time since surgery, indicating that satisfaction remained stable postoperatively (Figures 1-3). IPWRA revealed significant positive effects of MM on satisfaction (Table 3).

The mean scar aspect score was 3.1 (SD ±0.9), and the average time since surgery was 40 months (SD ±29.2, range, 3-147 months). The MCID was calculated as 8.94 for the BODY-Q Chest, 11.71 for the BODY-Q Nipple, and 4.77 for the BIS, representing the smallest score changes considered clinically relevant.

DISCUSSION

The authors of this study contribute to the literature by being the first in Brazil to use validated instruments, such as the BODY-Q and BIS, to evaluate the outcomes of MM in transgender men. Focusing on an underrepresented population in LMICs helps address gaps in understanding the healthcare needs of transgender men, a group that has often been overlooked in research. These findings highlight the sustained positive impact of MM on body image satisfaction, mental health, and social integration, offering initial benchmarks, such as MCIDs, for future studies. Furthermore, these results underscore the value of integrating masculinizing surgeries into public healthcare systems as a step toward reducing disparities and improving accessibility. By situating these findings within a global context, the authors of this study contribute to the ongoing dialogue on transgender healthcare policies and clinical practices, emphasizing the importance of culturally adaptable strategies for enhancing the well-being of transgender individuals worldwide.

These findings may have policy implications for expanding access to transgender healthcare in Brazil. Individuals in the MM group had significantly better body image and quality of life than their counterparts. Transgender men who align their physical appearance with their gender identity are likely to feel more confident in public spaces, potentially facing less external hostility. This underscores the need to make MM and BMPs more accessible through the public health system, which could positively impact both individual well-being and societal integration.^24,30-32 The influence of testosterone therapy on surgical outcomes and patient satisfaction with body image has been evaluated in several studies that found no significant associations between testosterone use and increased complications.³³

Global researchers also support the importance of comprehensive transgender healthcare.^20,34 In Brazil and across Latin America, transgender healthcare access is limited by persistent stigma, lack of provider knowledge, and insufficient resources within the public health systems, exacerbating health disparities among transgender individuals. Despite progressive policies in some countries (eg, Argentina's Gender Identity Law), structural health system limitations persist, and rates of violence against transgender people remain alarmingly high.³⁵ The higher average age of participants in our study may reflect the challenges that many transgender individuals in Brazil face in accessing BMPs within the public healthcare system. These delays are often because of logistical, financial, and social barriers, as well as the requirements set by current Brazilian policy, which mandates that individuals be at least 21 years old and undergo 2 years of multidisciplinary follow-up before qualifying for surgery. These factors contribute to a later age at surgery compared with populations in countries with more accessible healthcare services.³⁶

This cross-regional perspective underscores the need for inclusive and culturally adaptable transgender healthcare strategies that account for regional social and economic dynamics. The findings from Latin America align with similar barriers identified in underrepresented regions like Asia and Africa.^37,38 For example, a scoping review on transgender men in LMICs found that transgender men frequently face social exclusion, unprescribed hormone use, and gender-based violence, with limited access to appropriate healthcare across many regions.³⁹ Moreover, although we found no significant racial differences between the groups, we acknowledge that racial disparities may still influence surgical outcomes in the transgender population.^40,41

Similarly, studies in Kenya and Uganda noted significant healthcare access barriers for transgender men, including pervasive stigma, discrimination, and socioeconomic exclusion, which heighten their vulnerability to health risks and lead to delays in seeking necessary care.^42,43 The tools and approaches used in this study could be adapted to account for these regional differences by considering factors like stigma and social exclusion in healthcare settings.

To optimize surgical outcomes, various classification systems for chest masculinizing surgery have been proposed to guide the selection of surgical techniques based on individual breast characteristics and desired aesthetic results.⁴⁴ This study also explored the relationship between time since surgery and satisfaction with body image, chest appearance, and nipple aesthetics. Regression analysis revealed that satisfaction remained consistent over time, suggesting that MM has a long-lasting impact, which is consistent with previous research.⁴

Studies from Canada and Australia emphasize the importance of integrating transition-related care into public health systems to ensure equitable access.^14,45 Equitable access to these procedures could also mitigate the negative impacts of gender dysphoria, as seen in other countries with inclusive healthcare policies, such as Australia, where improved access to transition-related healthcare has been associated with better mental health and social outcomes for transgender populations.³⁴ Global research emphasizes the importance of BMPs in reducing healthcare disparities and promoting overall quality of life for transgender individuals.⁴⁶

We opted for the term “body modification procedures” instead of gender-affirming surgeries to reflect the views of many transgender individuals who believe their identities are already established, regardless of interventions. These treatments address gender expression, whether they support or challenge the male–female dichotomy.⁴⁷

Validated instruments, such as the BODY-Q and the BIS, reinforce that MM significantly improves self-reported outcomes related to self-perception and psychosocial functioning. These results support previous research showing substantial improvements in satisfaction with chest appearance and reduced body dissatisfaction after surgery.⁴⁸

Over 87% of the participants reported discrimination, and 25% faced violence. However, data from the MM group advocates a decrease in such experiences (the MM group reported no cases of violence and experienced a reduction in discrimination rates from 86.7% to 17.8% after surgery), suggesting that although MM significantly improves physical self-concept and alleviates gender dysphoria, it may also help minimize external hostility. Further research is needed to confirm this relationship. These results highlight the potential of BMPs to not only align physical appearance with gender identity but also improve the social environment for transgender individuals.

Many transgender men in the MM group no longer needed to wear chest binders after the procedure, whereas ∼75% of them referred to using chest binders before surgery. This finding is consistent with other studies showing that MM effectively aligns physical appearance with gender identity and reduces health risks associated with binding.^15,49,50 Discontinuing binder use postsurgery is associated with notable improvements in mental health, as binding often serves as a daily reminder of physical incongruence, exacerbating gender dysphoria.^50-52 Achieving an ideal chest appearance mitigates dysphoria, leading to enhanced mental health, as demonstrated in previous studies.^4,31

This study provides initial benchmarks for measuring changes in body investment and satisfaction after MM by defining the MCID values for BODY-Q Chest, BODY-Q Nipple, and the BIS. These benchmarks are essential for clinicians and researchers to evaluate the effectiveness of BMPs in improving quality of life, ensuring that the observed changes are not only statistically significant but also meaningful from the patient's perspective. These findings align with those of Bustos et al, who reported consistently high levels of patient satisfaction after MM, underscoring the importance of understanding and measuring how patients perceive changes in outcomes.⁴

This study confirms that MM plays a role in fostering self-acceptance and resilience among transgender men as they face societal challenges. MM contributes to greater psychological security and reduces the impact of discrimination and violence by aligning the physical appearance with gender identity. Given the high rates of violence against LGBTQIA+ people in Brazil, this study emphasizes the importance of BMPs in improving body image and self-esteem and potentially increasing safety through a more congruent physical appearance. These findings advocate expanding access to high-quality healthcare services for transgender individuals in Brazil, ensuring that they receive the support needed to live safer, more fulfilling lives.

Limitations and Strengths

This study has limitations, including its single-center design, which may limit the generalizability of the findings to the broader population of transgender men despite the inclusion of participants from various states. The cross-sectional design restricts the ability to establish causal relationships between MM and the observed outcomes over time. However, the use of IPTW helped mitigate this limitation. Additionally, the scarcity of validated instruments for transgender populations in Brazil reinforces the need for further research in this field.

Despite these limitations, this study had several strengths. Although the study was conducted at a single center, the participants represented 14 of Brazil's 26 states, thus enhancing the external validity and applicability of the findings. This is the first study in Brazil to use validated tools such as the BODY-Q Chest and Nipple scales and the BIS to assess outcomes after MM, thus improving the reliability and robustness of the results. Although causality cannot be established because of the cross-sectional design of this study, adjustment for covariates through IPTW helps mitigate potential biases stemming from differences between groups. The positive associations observed in MM group were likely a result of the intervention rather than inherent differences between groups. Estimating the MCID for these scales provides an important benchmark for future research and clinical practice. By focusing on an underrepresented population, this study addresses a significant gap, offering insights into the experiences of transmen in Brazil, supporting the benefits of MM, and advocating for expanded and accessible healthcare, particularly in countries with high rates of violence against LGBTQIA+ individuals.

CONCLUSIONS

This study highlights the role of MM in enhancing body image satisfaction, mental health, and social integration among transgender men in Brazil. These findings align with global research showing that BMPs improve both psychological and physical well-being, reinforcing the need for expanded public healthcare access to these procedures worldwide. Future research should explore the long-term benefits of MM to guide best practices in transgender health.

Acknowledgments

The authors express their sincere gratitude to Dr Martin Marcondes Castiglia, Medical Director of Pedreira Hospital, São Paulo, Brazil; Dr Adriano Guimarães Brasolin, Coordinator of Plastic Surgery at NúcleoTrans-Unifesp, São Paulo, Brazil; Dr Renata Azevedo, Deputy Coordinator at NúcleoTrans-Unifesp; and Dr Mariana Rosa Borges, Academic Deputy Coordinator at NúcleoTrans-Unifesp for their valuable support in providing access to information essential for patient recruitment. We would like to express our heartfelt gratitude to Prof. Magnus Régios Dias da Silva, Director of the Escola Paulista de Medicina, for his invaluable collaboration and for creating opportunities that allowed this project to come to fruition.

Disclosures

The authors declared no potential conflicts of interest with respect to the research, authorship, and publication of this article.

Funding

Dr Felix received funding from the Coordination for the Improvement of Higher Education Personnel (CAPES) as a doctoral scholarship. CAPES did not participate in any aspect of the research, including study design, data collection, data analysis, manuscript writing, or journal selection. There were no other financial or personal relationships with third parties or commercial entities within the past 36 months related to this study.

REFERENCES

Author notes