Brachytherapy Implant OncoSil May Improve Pancreatic Cancer Treatment
Pancreatic ductal adenocarcinoma (PDAC) is a very lethal disease, with an average of less than 10% of patients surviving for five years. Most tumors present with this cancer are unresectable, locally advanced, or metastatic when a diagnosis is achieved. Traditional treatments have not demonstrated significantly increased survival, exacerbating the issue. Then, the question becomes: what do medical professionals do about PDAC treatment?
Liv Hospital is utilizing a multimodal, conversion-to-surgery strategy for PDAC centered on OncoSil™, a Phosphorus-32 (P-32) radioactive microparticle implant delivered via endoscopic ultrasound (EUS). The goal is to shrink borderline or locally advanced tumors away from major vessels, improving patient eligibility for curative resection.
Problems with PCAD Treatment
Pancreatic tumors are often classified as borderline resectable or locally advanced unresectable, due to complications that frequently arise when considering operability. The location, which is often the reason for this classification, typically makes PCAD difficult to survive, in addition to late-diagnosis.
The pancreas itself is located deep in the upper abdomen and surrounded by important organs such as the stomach, small intestine, and spleen. Three major blood vessels cross behind the pancreas. The tumor(s) associated with PCAD may encase or invade these major vessels, or be located in the head of the pancreas, which is nearest to the small intestine and central to the body, causing R0 resection to be difficult.
Not only is surgery difficult, but diagnosis may often be troublesome. Symptoms of pancreatic cancer are often vague, ranging from abdominal pain, jaundice, and weight loss to new onset type-2 diabetes. Symptoms may often be similar to those of other diseases or illnesses, prolonging the diagnosis when time is slipping away.
What is OncoSil?
OncoSil, positioned as a brachytherapy, is intended to be delivered inside the tumor via injection of P-32 through EUS, contrasting with external beam radiotherapy, which can affect surrounding organs. Since OncoSil is injected directly into cancerous tissue, radiation is less likely to be administered in a broad area, limiting exposure for surrounding organs.
With EUS, the P-32 is delivered via the gastrointestinal tract, with a flexible tube fed through the mouth and down the esophagus and deposited close to the pancreas while the patient is sedated. A fine needle is then used to deposit OnsoSil into the tumor.
The protocol aims to reduce tumor volume and pull it back from critical vessels. Best case, this increases the chance of an R0 resection and shifts intent from palliation to potential cure for select patients.
In multiple reports, OncoSil is not suggested to be used as a singular treatment for PCAD. The treatment works best when used in combination with other treatments, as recently reported in an investigator-initiated study led by Prof. Martijn Meijerink, Interventional Oncologist at Amsterdam UMC. No reports or findings have been published by Meijerink at this time.
Multidisciplinary Team Treatment
OncoSil, per its instructions for use, requires a multi-personnel approach to treatment. Candidate review can be described as board-led, necessitating reviews and opinions from surgery, medical oncology, interventional radiology, and gastroenterology, followed by treatment sequencing, an observation window, and then re-staging before surgical planning.
OncoSil requires training before administration on the correct dilution method and delivery before patient use. This is an intense system with strong safety precautions due to the radioactive nature of the P-32 being administered. However, it has been accepted for use in Austria, Australia, Belgium, Greece, Israel, Italy, the Netherlands, New Zealand, Spain, Turkey, and the United Kingdom.
Patient Selection Criteria
Ideally, OncoSil is used on tumors that are locally advanced and unresectable or borderline resectable, without distant metastasis. The instructions recommend that the tumor be under 7cm in the longest diameter and under 110cc in volume.
Ideal candidates have sufficient functional status (Karnofsky ≥70) and fitness. As the treatment has not been tested on pregnant patients and does require radiation precautions, patients who are pregnant are likely excluded from receiving treatment. The patient’s guide to OncoSil recommends that all participants in the treatment take contraceptives following the 12-month period after receiving treatment.
Safety and Side Effects
OncoSil claims a favorable safety profile due to short-range beta emission confined to the tumor, creating minimal public exposure risk. The instructions claim that radiation is confined to the body, but the patient’s guide still suggests taking radiation precautions after using the bathroom, as some waste may contain traces.
Typical side effects from the treatment include:
- Abdominal pain and/or discomfort
- Nausea
- Vomiting
- Lethargy
- Fever
- Abnormal liver function tests
Looking Forward
Integrating specialized treatment may expand the boundaries of operability and improve outcomes for patients as data accumulates. Due to the location of the pancreas and pancreatic tumors, operation availability is limited or not available.
Diagnosis often arrives late, increasing the struggle for a solution, as symptoms can be difficult to trace to pancreatic cancer. By then, the operation is impossible. For now, one more treatment option may be available than previously: OncoSil.
OncoSil is delivered into the tumor to limit exposure to radiation, and all radiation is contained within the body. The treatment works best on locally advanced non-metastasized tumors to shrink the size of the cancer until it can be operated on. It is available to select patients and can be a viable treatment path for those suffering from pancreatic cancer.
This article is for informational purposes only and does not substitute for professional medical advice. If you are seeking medical advice, diagnosis or treatment, please consult a medical professional or healthcare provider.
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