Evolution of Gonadal Management in Complete Androgen Insensitivity Syndrome: A 25-Year Retrospective Cohort Study from a Dedicated Differences of Sex Development Service

BACKGROUND: Prophylactic gonadectomy has been historically recommended postpubertally for individuals with complete androgen insensitivity syndrome (CAIS) to mitigate gonadal malignancy risk. It is recognized that a proportion of individuals with CAIS choose to live with the risk of malignancy rather than undergo gonadectomy and subsequent long-term hormone treatment. METHODS: This retrospective study included all new postpubertal patients with CAIS seen between 2000 and 2025 at a single UK differences of sex development center. Demographic characteristics, presentation, histopathology, gonadal surveillance, and psychological data were reviewed. Descriptive statistics were used, with temporal trends analyzed using linear and logistic regression. RESULTS: This study included 187 patients diagnosed with CAIS, of whom 89/187 (47.6%) had genetic testing identifying a mutation affecting their androgen receptor gene. At review, 28/187 (15.0%) retained their gonads, with a significant increase in gonadal retention over time (P = .002). In the last 5 years, 76.5% opted for retention. Among the 28 individuals who chose to retain their gonads, 24/28 (85%) had a psychological review, with themes explored including identity, secrecy, repression of CAIS, health-related anxiety, and negative health care experiences. Of the group who had undergone gonadectomy (159/187, 85%), the median age at surgery was 17 years (IQR = 6-19), with a temporal trend toward increasing age at time of gonadectomy over time (P < .001). Of those with a confirmed androgen receptor mutation (n = 89) who underwent gonadectomy (40/89, 44.9%), histopathology was available in 40/89 (44.9%): malignancy was found in 1 (4.0%), precursor lesions in 4 (10.0%), and benign gonadal lesions in 22 (55%), most commonly Sertoli adenoma (18/40, 45%). CONCLUSION: An increasing proportion of individuals with CAIS are choosing to retain their gonads rather than have postpubertal gonadectomy. Malignancy incidence in this cohort was low, consistent with recent literature. Further work should explore decision-making factors and how gonadal function and malignancy risk in CAIS change through adulthood.