Susanne Wollaert is the Chief Executive Officer of the International Society of Paediatric Oncology (SIOP), the leading global professional organisation dedicated to improving outcomes for children and adolescents with cancer. Under her leadership, SIOP has strengthened its role as a global coordinating platform for paediatric oncology, supporting multidisciplinary collaboration across clinical care, research, education, and policy in more than 130 countries. She oversees the society’s operations, governance support, programs, budgets, and communications, working closely with SIOP’s Board, Secretariat, networks, working groups, and continental branches.
During Wollaert’s tenure, SIOP has expanded its global footprint and influence, particularly in low- and middle-income countries, and reinforced its contribution to capacity building, guideline development, and international research collaboration. Key advances include the growth of SIOP’s education and training initiatives, strengthened engagement with regional paediatric oncology networks, and increased alignment with global health partners to support implementation of the WHO Global Initiative for Childhood Cancer.
The 100 CEOs featured here reflect the diversity and complexity of modern oncology leadership. In 2025, some lead the world’s largest cancer institutions; others guide specialized societies or emerging innovators. What unites them is responsibility: for millions of patients, for the integrity of science, and for the future direction of cancer care globally.
This list is not a celebration of power, but a recognition of stewardship, accountability, and impact – and of the leaders whose choices continue to shape the fight against cancer. For the many deserving individuals not mentioned in this list, we will continue to acknowledge, honor and elevate your voices in our daily publications from across the world.
See the full list of The 100 Influential CEOs in Oncology in 2025 and stay tuned for other special category nominations.
