OR27-02 An Exploration of Novel Clinical Benchmarks for Assessing the Practice of Gonadectomy in Conditions Affecting Sex Development - on Behalf of the I-DSD Consortium

Introduction: Although the practice of gonadectomy in the field of differences/disorders of sex development (DSD) has undergone intense scrutiny, objective knowledge regarding current practice of gonadectomy is lacking in conditions affecting sex development. Methods: The International DSD Registry (www.I-DSD.org) was examined for clinical information reported by the DSD specialist centre on age at presentation, year of birth, diagnosis, karyotype, sex of rearing and age at gonadectomy in all cases over the age of 16 years at the time of search and who had a disorder of androgen action or synthesis, gonadal dysgenesis or a non-specific DSD.Results: Of the 3,618 cases available in the registry, 757 (21%) met the inclusion criteria and data regarding gonadectomy status were available in 668 (88%) from 44 participating centres. Of these, 248 (37%) with a median age of 24 years (range 17, 75) were registered as male and 420 (63%) with a median age of 26 years (16, 86) were registered as female. Gonadectomy was reported from 36 centres in 351 of these 668 cases (53%) of whom 302 (86%) had a 46 XY karyotype. Females were more likely to undergo gonadectomy (n=311, p<0.0001) and the most common diagnoses were complete androgen insensitivity syndrome (n=161, 24%) and partial gonadal dysgenesis (n=94, 14%). Of the 351 cases, the primary indication for gonadectomy was reported in 268 (76%) cases and included mitigation of tumourigenesis risk in 172 (64%), conformity to sex assignment in 74 (28%) and another indication in 22 (8%). Gonadectomy was bilateral in 295 (84%), unilateral in 16 (5%) and unknown in 40 (11%). The median ratio for age at first presentation to age at gonadectomy in those who presented before the age of 5 years and those who presented after the age of 10 years was 0.1 (range) and 0.9 (range), respectively (p<0.0001). Of the 351 cases, 17 (5%) had undergone a gonadectomy before their first presentation to the specialist centre and these cases were distributed across 9 of the 36 centres. Conclusions: Not only does the rate of gonadectomy vary according to underlying diagnosis and sex of rearing, it also seems that there is a variable discrepancy between the age at presentation and age at gonadectomy. The use of this objective marker to identify trends in practice may improve our understanding of the causes of variation.