OncoSil™

What Is OncoSil™?

OncoSil™ (originally developed as BrachySil™) is a medical device used in brachytherapy, delivering radioactive Phosphorus-32 (32P) loaded microparticles directly into pancreatic tumours. It is a single-use brachytherapy (internal radiation) device that delivers a pre-determined dose of beta radiation directly into cancerous tissue.

The microparticles are tiny, ranging from 28 to 32 micrometres in diameter, smaller than a human hair. Once implanted, they remain permanently in the tumour.

Primary Indication

OncoSil™ is used to treat patients with locally advanced unresectable pancreatic cancer (LAPC). This type of cancer remains confined to the pancreas and nearby structures but is considered unresectable when the tumour is too large or too close to nearby blood vessels to be removed safely with surgery.

It is used in combination with gemcitabine or FOLFIRINOX chemotherapy regimens as a treatment option for locally advanced unresectable pancreatic cancer.

Mechanism of Action

The beta particles emitted by OncoSil™ travel a short distance in tissue, causing damage to cancer cell DNA and rendering the cells incapable of further division and proliferation. Phosphorus-32 has a half-life of about 14.27 days, meaning its radioactivity halves roughly every two weeks. Within approximately 81 days, more than 98% of its radiation energy has been absorbed by the surrounding tumour tissue, allowing sustained local effect while limiting systemic radiation exposure.

Compared to external beam radiation therapy, OncoSil™ is designed to deliver approximately double the radioactivity dose to the tumour without significantly increasing side effects, while favouring quality of life through a single hospital visit.

Treatment Goals

The aim of OncoSil™ therapy is to reduce tumour size by destroying cancerous tissue. In some patients this can make the tumour eligible for surgical resection. More broadly, the main objectives are local tumour control, potential downstaging, and, where possible, enabling eventual surgical removal.

Administration Procedure

• OncoSil™ is injected directly into the tumour under endoscopic ultrasound (EUS) image guidance.
• This endoscopic ultrasound procedure is a standard technique performed by a trained physician.
• Follow-up imaging typically includes a SPECT scan on Day 1 and Day 7 post-implantation to confirm correct placement and dosimetry.
• Delivery requires a multidisciplinary team, including an oncologist, abdominal surgeon, endoscopist, and nuclear medicine physician, with physicians trained through a dedicated OncoSil Medical training programme.

Regulatory Status

• OncoSil™ received European CE marking in April 2020 for treatment of locally advanced pancreatic cancer in combination with chemotherapy, enabling use in the EU and UK.
• It holds breakthrough therapy status in the EU, UK, and USA.
• It has also received regulatory approval in Hong Kong, and OncoSil Medical operates across markets in Europe and Asia Pacific, headquartered in Sydney, Australia.
• In some markets (e.g., the UK), it is currently accessed privately, through medical insurance or self-pay at approved treatment centres, rather than through standard public healthcare funding.

Clinical Context and Rationale

Pancreatic cancer is notoriously difficult to treat, largely because it is often diagnosed at an advanced stage. Its aggressiveness, combined with the complexity of managing locally advanced disease, has driven the search for novel therapies. Surgical resection remains the only potentially curative treatment, but survival in advanced-stage disease remains poor despite chemotherapy and radiotherapy.

OncoSil™ can be combined with chemotherapy regimens such as FOLFIRINOX or nab-paclitaxel plus gemcitabine, enabling simultaneous local and systemic disease control. Ongoing clinical trials continue to evaluate its long-term impact on survival and quality of life, with early data suggesting that combining local radiotherapy with systemic therapy improves both local disease management and patient comfort.

Summary Table

Note: This is general medical/educational information, not a substitute for professional medical advice. Decisions about OncoSil™ or any pancreatic cancer treatment should be made in consultation with the qualified oncology team at Liv Hospital, since suitability depends on individual disease stage, anatomy, and overall health.