Defining Outcomes in Facial Gender-Affirming Surgery: A Systematic Review to Inform Core Outcome Set Development

Facial gender-affirming surgery (FGAS) is a transformative step for transgender individuals in their gender care journey. Even so, the way outcomes are measured and re-ported is highly inconsistent and unstudied. This limits the ability to compare studies or develop clear, patient-centered benchmarks for success. We systematically assess how current research defines FGAS outcomes and lay the groundwork for a unified core outcome set (COS). A comprehensive PubMed search identified 334 studies on FGAS published through March 2025. After screening, 232 studies met inclusion criteria, en-compassing 30,937 patients. Data were extracted on study characteristics, surgical pro-cedures, outcome domains, measurement tools, and follow-up duration. Descriptive statistics and chi-square analyses were used to evaluate reporting trends. Most studies emphasized aesthetic outcomes (61.6%) and complications (60.0%), fewer addressed psychosocial well-being (45.7%), quality of life (21.6%), or reoperation rates (20.7%). Only 26 of the 232 studies used validated outcome instruments, such as FACE-Q or PROMIS (p < 0.001). Among studies that reported satisfaction, only 41.2% provided numerical or stratified scores. Outcome reporting in FGAS research is fragmented and dominated by subjective or unvalidated assessments. A standardized COS is needed to unify research practices, facilitate meaningful comparisons, and ensure that outcomes align with pa-tient-defined measures of surgical success.