High BMI as risk factor in mastectomy in transmasculine individuals: a retrospective matched case-control study

Obesity as a risk factor in gender-affirming surgery is a hot topic. Though obesity is considered a risk factor for certain surgical complications, BMI cutoffs may be a barrier to surgical care for transgender individuals. All transgender individuals that underwent gender-affirming mastectomy in our center were retrospectively identified from a departmental database. Every transgender individual with a BMI > 34kg/m² was matched 1:1 to an individual with a BMI between 18 and 25 kg/m², based on: surgical technique, surgeon, smoking, resection weight (+/-150 grams), and comorbidity such as diabetes and cardiovascular diseases. A retrospective chart study was conducted, recording demographics, surgical characteristics, short- and long-term complications and reoperations. Complications were ordinally categorized according to the Clavien-Dindo (CD) classification. Outcomes of groups were compared. A total of 53 individuals with BMI > 34 who underwent mastectomy were matched to 53 non-obese individuals according to the abovementioned matching criteria. A total of 44 (83%) non-obese individuals had a complication-free trajectory, versus 23 (43%, p < 0.01) in the obese group. Seroma occurred more frequently in obese individuals (n = 16 (30%) vs 2 (4%), p < 0.01). Looking at de CD rating system, obese individuals experienced more complications overall (p < 0.01). However, complications were mostly CD grade I or II. Secondary surgical chest contour corrections were performed in 9 (17%) obese versus 2 (4%) non-obese individuals. CD grade III complications occurred in 10 (18%) obese individuals and in 4 (8%) non-obese individuals. There were no grade CD grade IV or V complications. Mastectomy in individuals with obesity seems safe with regard to major complications. However, minor complications and revision surgery are significantly more frequently present in these individuals. Preoperative counseling should focus on the higher risk on complications and reoperations.