Controversies in the organization and structure of management for rare tumors.

Abstract

More than half of all gynecological cancers are classified as rare (annual incidence <6 per 100,000), and present significant challenges in diagnosis, management, and research. Rare cancers collectively comprise more than 20% of new cancer diagnoses and exceed the burden of individual common cancers. Their rarity complicates evidence-based guideline development, clinical trial design, and drug access, and is exacerbated by variations in epidemiology, histology, and biological behavior. Key controversies include the need for centralized pathological reviews and harmonized diagnostic criteria. Recent World Health Organization classification updates, such as the redefinition of ovarian and fallopian tube cancers, illustrate the impact of evolving guidelines on epidemiology and patient management. Variations in the classification among pathologists and limited access to molecular diagnostics further hinder effective management. Multidisciplinary care in expert centers improves outcomes; however, significant geographic and resource disparities persist. National and international collaborations including European Reference Network for rare adult solid tumors, Gynecologic Cancer Intergroup, Gynecologic Oncology Group, Asia-Pacific Gynecologic Oncology Trials Group, and European Network for Gynaecological Oncology Trials have made strides in standardizing care and advancing research. Novel trial designs, such as basket and umbrella trials, alongside synthetic control arms, are essential for addressing the small sample sizes typical of rare tumors. Emerging consortia, such as International Ovarian Tumor Tissue Analysis Consortium and International Consortium for Low-grade Serous Ovarian Cancer, provide robust platforms for translational research and biomarker validation. However, challenges remain in fostering cross-border collaboration, streamlining regulatory pathways, and ensuring equitable access to trials and therapy. To optimize outcomes, a comprehensive approach that integrates centralized care, innovative trial designs, and international networks is imperative. This paradigm fosters the harmonization of care, accelerates translational research, and bridges the gap between scientific innovation and patient benefits.