OncoSil Data at ASCO Shows 13.7% Surgical Conversion in Inoperable Pancreatic Cancer
Spanish clinical data lands at ASCO 2026 — what the results mean for OncoSil Medical
An abstract featuring Spanish multi-centre clinical experience with the OncoSil™ device has been accepted for poster presentation at the American Society of Clinical Oncology (ASCO) Annual Meeting 2026, taking place 29 May to 2 June 2026 in Chicago. OncoSil Medical Limited (ASX: OSL) confirmed the data will be presented by Dr Carmen Guillen-Ponce from Hospital Universitario Ramón y Cajal, Madrid, on 30 May 2026 in the Gastrointestinal Cancer—Gastroesophageal, Pancreatic, and Hepatobiliary session.
The ASCO Annual Meeting is one of the world’s leading oncology congresses, and acceptance of this abstract reflects growing international clinical interest in the OncoSil™ device as a treatment option for patients with unresectable locally advanced pancreatic cancer (LAPC).
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What the Spanish multi-centre data showed across 51 patients
The accepted abstract is titled: “Experience of Spanish centers with echoendoscopically implanted 32P microparticles associated with chemotherapy in locally advanced pancreatic adenocarcinoma.” It reports outcomes from 51 patients with unresectable LAPC treated across Spanish centres using the OncoSil™ device, delivered via endoscopic ultrasound (EUS).
Key clinical outcomes at a glance
- Favourable safety profile: only two adverse events considered related to OncoSil™ treatment (mild gastric pain and weakness)
- 7 of 51 patients (13.7%) initially deemed unresectable subsequently underwent surgery, including 5 R0 resections (completely clear surgical margins devoid of cancerous cells)
- Median progression-free survival (PFS) from OncoSil™ treatment: 8.5 months (95% CI 5.3–17 months)
- 33 patients alive at end of follow-up (64.7%); median overall survival since OncoSil™ treatment: 15.6 months (95% CI 10.2–26.9 months)
- Investigators concluded: intratumoural OncoSil™ treatment plus gemcitabine-based chemotherapy is safe, with encouraging survival outcomes and surgical rescue achieved in a high percentage of initially unresectable patients
| Metric | Result | Patient Cohort | Clinical Significance | Notes |
|---|---|---|---|---|
| Adverse events related to OncoSil™ | 2 events | 51 patients with unresectable LAPC | Supports favourable safety profile | Mild gastric pain and weakness |
| Surgical conversion rate | 13.7% (7/51) | Initially unresectable patients | Meaningful outcome in an otherwise inoperable population | 5 of 7 achieved R0 resection |
| R0 resection rate (of surgical conversions) | 5 of 7 patients | Surgically converted patients | Completely clear surgical margins — optimal surgical outcome | — |
| Median progression-free survival | 8.5 months (95% CI 5.3–17 months) | 51 patients | Reflects disease control duration post-treatment | From OncoSil™ treatment initiation |
| Median overall survival | 15.6 months (95% CI 10.2–26.9 months) | 51 patients; 33 alive at follow-up (64.7%) | Notable survival duration for a typically poor-prognosis disease | From OncoSil™ treatment initiation |
A patient alive 50 months on — the Cureus case report
Alongside the ASCO abstract, a peer-reviewed case report published in Cureus journal from Hospital Universitario de Fuenlabrada, Madrid, provides additional supporting evidence. The case describes a patient with initially unresectable LAPC who achieved long-term disease-free survival following OncoSil™ treatment.
Key findings from the case report:
- Patient initially diagnosed with unresectable pancreatic adenocarcinoma in the head of the pancreas
- OncoSil™ microparticles administered following induction chemotherapy (gemcitabine + nab-paclitaxel)
- No device- or procedure-related adverse events observed
- Successful surgical resection achieved 7.9 months after diagnosis
- As of January 2026: patient alive with no evidence of disease, 50 months post-diagnosis and 42 months post-resection
The authors concluded that the addition of OncoSil™ microparticles to first-line chemotherapy was associated with disease stabilisation and conversion to surgical resection in this patient.
Nigel Lange, CEO & Managing Director
“We are pleased to see the Spanish clinical experience with the OncoSil™ device recognised at ASCO Annual Meeting 2026. Spain has become the leading country for the routine clinical adoption of OncoSil™, and is one of our most experienced markets globally, with clinicians continuing to demonstrate leadership in integrating this innovative therapy into everyday practice. The results presented in this abstract are encouraging, demonstrating a favourable safety profile, promising survival outcomes and the potential for surgical conversion in some patients initially considered unresectable. We are also encouraged by the recently published case report from Hospital Universitario de Fuenlabrada, which demonstrated successful surgical resection and long-term disease-free survival following treatment with the OncoSil™ device in a patient with initially unresectable locally advanced pancreatic cancer. We sincerely thank the Spanish investigators and treating clinicians for their commitment to improving outcomes for patients with unresectable locally advanced pancreatic cancer.”
Why LAPC is one of oncology’s hardest problems — and how OncoSil™ targets it
Unresectable locally advanced pancreatic cancer refers to a tumour that cannot be surgically removed at diagnosis due to its proximity to critical blood vessels or surrounding structures. Pancreatic cancer is the 12th most common cancer in men and the 11th most common cancer in women globally, with approximately 500,000 new cases diagnosed annually. Because it is typically detected at a later stage, long-term prognosis remains poor.
The OncoSil™ device addresses this by delivering Phosphorous-32 (32P) microparticles directly into the tumour via endoscopic ultrasound (EUS). This intratumoural approach allows a greater radiation dose to be concentrated at the tumour site while sparing surrounding critical organs, contrasting with external beam radiotherapy, which delivers radiation from outside the body and may affect healthy tissue in the path of the beam.
OncoSil™ holds CE Marking (providing marketing authorisation in both the EU and the UK), is approved for sale in 30+ countries, and has been designated a breakthrough device in both Europe and the United States. Surgical conversion to R0 resection represents the most meaningful clinical outcome achievable for LAPC patients otherwise considered inoperable. The 13.7% conversion rate observed in the Spanish cohort gives important context for the device’s potential role in this setting.
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Spain as the proof-of-concept market — and what comes next
Spain has emerged as OncoSil’s most experienced commercial market and the leading country for routine clinical adoption of the OncoSil™ device, as highlighted by management. Independent investigator-led data presented at a congress of ASCO’s standing supports broader clinical confidence in the device.
Commercial treatments using the OncoSil™ device are already underway across multiple markets, including:
- Spain, Italy, Austria, Germany
- Greece, Türkiye, Portugal
- Israel and the United Kingdom
The ASCO 2026 poster presentation reinforces the strength of the company’s real-world clinical evidence base, with data generated by independent clinicians across a multi-centre Spanish cohort. As OncoSil continues to build its commercial footprint across Europe and beyond, peer-reviewed publications and major congress presentations serve as important markers of clinical adoption. For further information, visit www.oncosil.com.
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