The SIOP 2025 Congress – the 57th Annual Meeting of the International Society of Paediatric Oncology – took place in Amsterdam, the Netherlands, from October 20 to 23, bringing together the global childhood cancer community to advance outcomes across every stage of paediatric oncology care. Hosted at RAI Amsterdam, the congress reaffirmed its role as a premier forum for precision medicine, multidisciplinary collaboration, and real-world implementation in paediatric cancer.
This year’s scientific program spanned solid tumours and haematologic malignancies, with sessions highlighting progress in molecular diagnostics, data sharing to inform policy and practice, and translational research that is reshaping risk stratification and therapeutic decision-making. Discussions spotlighted biomarker-driven approaches, the integration of systemic and local therapies, and strategies to accelerate equitable access to innovation worldwide.
With four days of cutting-edge presentations, expert debates, and networking, SIOP 2025 emphasized clinically meaningful insights with direct relevance to patient care – while also strengthening global collaboration through initiatives and assemblies tied to the wider paediatric oncology ecosystem.
Firmly established as a cornerstone of the oncology calendar, SIOP 2025 once again demonstrated how coordinated science, policy, and practice can accelerate a world where no child should die of cancer.
Here are the key highlights from SIOP 2025 Congress:
International Society of Paediatric Oncology – SIOP:
“Thank you for joining the SIOP Congress Fun(d) Run and Walk!
Your energy, enthusiasm, and support help make a real difference for children with cancer. Together, we’ve taken steps toward a brighter future and raised crucial funds for the University Hospital Center ‘Mother Teresa’ in Tirana, Albania.
We hope you enjoyed the run, the connections, and the fun!”
Proceed to the video attached to the post.
International Society of Paediatric Oncology – SIOP:
“It’s the final day of SIOP Congress! Get ready for a packed program of educational talks, engaging discussions, and opportunities for networking and collaboration. Don’t forget to stay social and share your moments in the MySIOP Photo Contest!
The first sessions start at 7:30, see you soon!”
“Great Day 1 at SIOP Congress in Amsterdam!
The World Child Cancer USA team presented their vision for the future at ‘Speak my Language: Rethinking Patient-Centered Communication in Childhood Cancer‘ in our panel alongside parents and experts in healthcare.
The evening’s keynote session spoke to more than 120 countries represented and attending this year’s conference, and we’re excited to continue connecting this week.
Stay tuned for more from Monday’s panel that will change the way you view the future of pediatric cancer communications!”
“We’re all set for today’s ACT 4 Children Symposium at SIOP Congress!
Today’s session, ‘From Access to Cure: How Innovative Medicines, Protocols, and Support Can Change Childhood Cancer Outcomes,’ features a collection of our partners detailing all the exciting innovations from ACT for Children!
Learn how we’re supporting low- and middle-income countries with drug access, medical training, data collection, long-term care, and much more.”
Shushan Hovsepyan, Editor-in-Chief of OncoDaily Medical Journal and Co-Chair of the International Society of Pediatric Oncology Global Health Network Research and Innovation Working Group:
“Just a few hours earlier, I was on a plane from ESMO2025 Berlin – and now I am standing on the International Society of Paediatric Oncology – SIOP stage in Amsterdam, with my story on the big screen.
It was a great honor and pleasure for me to receive the Young SIOP Rising Star 2025 Award! This was truly an unforgettable experience, standing in that huge theatre auditorium and sharing my short but long story.
I come from a small city, Gyumri, Armenia. We may be small, but we have produced world champions. Growing up in that environment, in the spirit of fighting, striving, and never giving up, is in my character because of that.
Four years ago, I attended my first SIOP Annual Meeting in Barcelona. I was in the audience watching people present, share their data, their stories…
I remember thinking, one day I should be up there… And now I am!
Thank you, International Society of Paediatric Oncology – SIOP, for giving me this opportunity!
And this moment was not about me, but about the people who encountered me along the way and always supported me in different ways.”
Ruzanna Papyan, Clinical Research Physician at Immune Oncology Research Institute:
“Highlights from the Sarcoma Session, Day 3, SIOP2025, Amsterdam
An inspiring day exploring functional recovery, molecular discoveries, and evolving prognostic insights across pediatric bone and soft tissue sarcomas.
Functional outcomes after local therapy for pediatric bone sarcoma.
Leonie Tigelaar, Princess Máxima Center.
From a nationwide cohort, satisfaction with daily participation was driven by fatigue and perceived restrictions, not by surgical type.
- Underscores the need for psychosocial support and individualized rehabilitation beyond physical recovery.
Regional lymph node invasion in pediatric NRSTS (INSTRuCT analysis)
Daniel Orbach et al.
In nearly 2,000 patients, RLNI was rare (<8%) but associated with aggressive histotypes such as epithelioid and clear cell sarcoma.
- Excellent regional control (96%) was achieved through cooperative protocols.
Title: Lymph Node Staging and Treatment in Pediatric Patients With Soft Tissue Sarcomas: A Consensus Opinion From the Children’s Oncology Group, European paediatric Soft Tissue Sarcoma Study Group, and the Cooperative Weichteilsarkom Studiengruppe
Authors: Sheila Terwisscha van Scheltinga, Reineke A. Schoot, Jonathan C. Routh, Guido Seitz, Simon C. Kao, Bart de Keizer, Barry Shulkin, Roelof van Ewijk, Beth McCarville, Dana Casey, Wendy Allen-Rhoades, Federico Mercolini, Hans Merks, Daniel Orbach, Tejas Kapadia, David O. Walterhouse, Raquel Davila Fajardo, Laura Hiemcke-Jiwa, Christiane Franzius, Federica De Corti, Vivian Tang, Jonathan Metts, Saphna Oberoi, Christian Vokuhl, Roshni Dasgupta, Suzi Birz, David Rodeberg
Read the Full Article in PubMed.
CWS-96 and CWS-2002P trials: localized NRSTS
Amadeus Heinz, University of Tübingen.
European data reaffirm that complete resection alone cures low-risk NRSTS.
Adjuvant radiotherapy or dose-intensified chemotherapy does not improve survival after R0 resection.
- Surgical resection remains the cornerstone of cure in localized disease.
Response–survival correlation in relapsed/refractory rhabdomyosarcoma
Lucy Shepard, University of York.
From the REFoRMS living review, the Disease Control Rate (DCR) shows the strongest correlation with survival.
- This supports DCR as a pragmatic endpoint for early-phase RMS trials.
YWHAE::NUTM2 soft tissue sarcomas in infants
Sarah Winter, Institut Curi.
YWHAE::NUTM2 – One transcript several diseases. (Endometrial stromal sarcoma, CNS tumors, undifferentiated round curl sarcomas, CSSK). Extremely rare, highly aggressive infant sarcomas with YWHAE::NUTM2 fusions show transient chemosensitivity and early brain metastases.
- Routine RNA-seq screening may allow earlier multidisciplinary intervention.
PCR detection of bone marrow metastases in Ewing sarcoma
Uta Dirksen, University Hospital Essen.
PCR identified occult bone marrow disease undetected by microscopy, with positivity linked to poorer prognosis, particularly in metastatic cases.
- Molecular tools may help refine future Ewing staging and risk stratification.
A day rich in science, collaboration, and shared commitment to improving sarcoma outcomes worldwide.”
Alejandra Mendez, Vice President of Childhood Cancer International:
“Being part of the International Society of Paediatric Oncology – SIOP and Childhood Cancer International Annual Congress is always a truly unique experience. This year, in beautiful Amsterdam, I’ve had the opportunity to meet wonderful people – each with inspiring stories, experiences, and a shared commitment to improving the lives of children with cancer.
This gathering gives me the opportunity to listen, learn, question, reflect, and build strong connections.
Every day is so special – thank you to everyone who makes this possible.”
“Key Highlights and Take-Home Messages from the Neuroblastoma Session
The Neuroblastoma session featured inspiring talks, showing the progress across the disease:
- Low-risk mediastinal neuroblastoma (Kachanov et al., Russia)
Patients with posterior mediastinal tumors demonstrated excellent 5-year OS (95%), though local relapses (16%) remain the main challenge. Most deaths were related to treatment toxicity rather than progression, emphasizing the need for therapy de-escalation.
- High-risk neuroblastoma: TPOG NB-2020 protocol (Kizmazoglu and Olgun et al, Türkiye)
Among 222 high-risk patients, immunotherapy during maintenance led to superior EFS (73% vs. 55%) compared to conventional chemotherapy, marking a major improvement from earlier national outcomes (TPOG-NB-2009 3-yr OS: 52%). Although not statistically significant, the trend supports integration of anti-GD2–based immunotherapy in standard protocols.
- Dinutuximab beta long-term infusion (Holger Lode et al., SIOPEN)
In the landmark HR-NBL1/SIOPEN trial (n=705), long-term infusion (10-day schedule) of dinutuximab beta significantly improved 5-year EFS (65% vs. 56%) and reduced relapse incidence compared to short-term infusion, with a better safety profile. These results firmly position LTI as the preferred administration method for anti-GD2 immunotherapy.
- Catecholamines as diagnostic and prognostic biomarkers (Lieve Tytgat et al., SIOPEN Catecholamine Committee)
An 8-metabolite urinary panel enhanced diagnostic sensitivity by 11% (and 46% for MIBG-negative cases) versus standard VMA/HVA testing. Elevated 3-methoxytyramine levels correlated with MYCN/MYC activity and poorer survival. Catecholamine positivity in patients deemed in remission predicted relapse risk (5-yr EFS 38% vs. 80%). This panel may refine diagnosis, risk stratification, and response monitoring.
- Oncolytic Zika virus therapy (Joseph Mazar et al., USA)
Preclinical data revealed >90% tumor regression and survival advantage in both MYCN-amplified and non-amplified models, including cisplatin-resistant lines. No tumor recurrence was seen post-ZIKV treatment. This innovative approach offers promise as a bridge therapy for chemotherapy-refractory high-risk neuroblastoma.
- Circulating GD2 for liquid biopsy (Ivanov et al., Russia)
Using HPLC-MS/MS, plasma GD2 showed high specificity (96%) and diagnostic accuracy – outperforming NSE and LDH. Elevated GD2 correlated with advanced stage, MYCN amplification, and 1p36 aberrations. Ongoing studies will assess its value for response and survival prediction.
And last but not least – it was wonderful to reconnect with our GNN family, catching up with old friends and meeting new ones along the way.
(Sorry for the missing people in the photo – you were there in spirit!)”
Jordan Gilleland Marchak, Associate Professor at the Emory University School of Medicine:
“Wonderful session – thank you to the SIOP PPO team for bringing together such an inspiring global group!
I loved sharing our SEE-SAD-ACT project, which screens childhood cancer survivors for anxiety and depression right at the point of care at Children’s Healthcare of Atlanta, so we can connect families to support sooner.”
International Society of Paediatric Oncology – SIOP:
“SIOP PPO brings together psycho-oncology researchers and clinicians from different parts of the world! In our Free Paper Session in Hall 8 this afternoon, we heard about….
Dr Kelly La Van Bindsbergen on PROMS – Dr Jordan Gilleland Marchak, on the SEE-SAD-ACT and Prof Lamia Barakat on the PAT….”
International Society of Paediatric Oncology – SIOP:
“Day 3 of the SIOP Congress may be winding down, but the evening is just getting started!
Join us at 19:30 for the Spectacular Networking Extravaganza in the Europe Foyer at the Congress Venue. Connect, celebrate, and enjoy an unforgettable evening with colleagues from around the world!”
You can also read Highlights From SIOP 2025 Congress: Part 1
