February 18, 2015 — Researchers at University Medical Center (UMC) Utrecht are developing an innovative cancer treatment involving the injection of radioactive beads into tumors, thereby enabling a very precise localized radiotherapy. The treatment is being developed with the help of a grant from Alpe d’HuZes/Dutch Cancer Society (KWF) of nearly 300,000 euros.
Direct injection of radioactive beads may be an effective treatment of tumors that are difficult or impossible to remove surgically. This is the basic principle of medical biologist Frank Nijsen, M.D., dental surgeon Robert van Es, M.D., and nuclear physician Marnix Lam, M.D., of UMC Utrecht. They are working together with Bas van Nimwegen, M.D., of the Faculty of Veterinary Medicine of Utrecht University to treat head and neck tumors with radioactive beads.
The treatment involves holmium microspheres that appear on a magnetic resonance imaging (MRI) or a nuclear scan. Using image-guided injection, the microspheres can be inserted into a tumor in a highly precise and localized fashion. In the first three millimeters, the holmium microspheres emit 90 percent of their radiation. The treatment is radically different from similar approaches involving radioactive yttrium microspheres. Holmium microspheres can be located using MRI, computed tomography (CT) and nuclear imaging techniques. This enables improved monitoring of the holmium treatment’s safety and effectiveness.
In collaboration with the Faculty of Veterinary Medicine of Utrecht University the treatment is now being tested in pets with tumors. The preliminary results are positive. Over the past four years, 15 cats and dogs have been treated for predominantly aggressive tongue tumors. The treatment was effective in the majority of animals. On average, tumor size was reduced by 80 percent and the tongue could still be used.
“The results in these animal patients are very promising,” said Ron Koole, M.D., of the Department of Oral and Maxillofacial Surgery of UMC Utrecht. “That is why I brought together scientists working on this subject to make the treatment available to human cancer patients as well."
The grant from Alpe d’HuZes/KWF will be used by the Utrecht researchers to expand their activities in this field. This should result in a phase I clinical trial studying the safety of the treatment in cancer patients. One of the most important questions is how these microspheres should be injected in order for them to effectively spread within the tumor and produce maximum effect. Possible side effects of the treatment should also be identified.
“Head and neck tumors are of course only one application of this treatment,” says Frank Nijsen, M.D., of UMC Utrecht. “In principle, it is possible to treat any fixed tumor that can be reached with a needle with holmium microspheres. However, we first need to prove that we can inject tumors repeatedly and in a controlled manner.”
For more information: www.umcutrecht.nl
May 03, 2025 
