Hersentumor: patiënt onwetend over slechte resultaten protonentherapie

The Shadow Over Proton Therapy: A Promise Unfulfilled?

Wouter Slegt’s story is a stark reminder of the complexities and potential pitfalls of cutting-edge cancer treatment. Four years ago, the 42-year-vintage was diagnosed with a glioom, a type of brain tumor. His wife, Oetje, a clinical neurophysiology specialist, urged him to get an MRI. After a diagnosis of a ping-pong ball sized tumor, Wouter was told he had ten to fifteen years to live with surgery, radiation and chemotherapy. He was also a candidate for proton therapy, a precision radiation technique available in Groningen, Maastricht, and Delft.

A Precision Approach with a Hidden Risk

Proton therapy utilizes positively charged particles that deposit their energy directly into the tumor, minimizing damage to surrounding healthy tissue. This represents particularly crucial in the brain, where preserving cognitive function is paramount. The promise of reduced side effects, such as memory loss, made it an attractive option for patients like Wouter, who had a long life ahead. Yet, a troubling discovery emerged in May of last year: patients with glioom grade 3 treated with proton therapy were experiencing significantly poorer outcomes – a fivefold increase in the risk of early death – compared to those receiving conventional radiation.

Delayed Disclosure and Growing Concerns

The three proton centers in the Netherlands halted treatment for glioom grade 3 patients, but this information wasn’t immediately shared with those already undergoing therapy, including Wouter. He completed his treatment in July, unaware that concerns had been raised. Over 100 patients had been treated with proton therapy for this type of tumor since 2019, and none were informed of the potential risks until media attention forced the issue in November 2025. The centers initially cited a desire to avoid “unnecessary unrest” as the reason for the delay.

A History of Lobbying and Questionable Evidence

The establishment of proton therapy centers in the Netherlands wasn’t without controversy. A group of doctors had long advocated for the technology, successfully lobbying for its implementation despite initial skepticism from the Dutch Healthcare Institute. Concerns were raised about the lack of robust comparative studies demonstrating its superiority over conventional radiotherapy. The group argued that the physics of proton therapy inherently made it at least as effective, and potentially superior, and that delaying treatment for research would be unethical. The Healthcare Institute ultimately approved the treatment, but questions about its value persisted.

The Search for Answers and International Repercussions

The Dutch findings have sent ripples through the international medical community. Researchers in Scandinavia, who were conducting long-term studies comparing proton and photon therapy, temporarily paused enrollment of glioom grade 3 patients to assess the potential risks. The possibility that the precision of proton therapy might be its downfall – potentially missing microscopic tumor cells surrounding the main mass – is being investigated. Some theorize that the focused beam may not eradicate these satellite cells, leading to faster recurrence.

What Went Wrong?

The case raises critical questions about the balance between innovation, patient safety, and the rigorous evaluation of recent medical technologies. The initial lack of transparency and the delayed disclosure of the concerning data have eroded trust in the proton therapy program. Wouter Slegt’s experience, and that of other patients, underscores the importance of informed consent and the need for ongoing monitoring and research to ensure the benefits of new treatments outweigh the risks.

Proton vs. Photon Therapy: A Closer Look

Proton therapy utilizes subatomic particles that deposit their energy precisely at the tumor site, minimizing damage to surrounding tissues. This is achieved through the unique properties of proton beams, which release their energy in a concentrated burst. Conventional radiotherapy, uses photon beams, which deposit energy gradually as they pass through the body. While effective, photon therapy can result in greater exposure to healthy tissue.

Frequently Asked Questions

• What is a glioom? A glioom is a type of brain tumor that can be aggressive and difficult to treat.
• What is proton therapy? Proton therapy is a type of radiation therapy that uses protons to target tumors with greater precision.
• Why were proton therapy treatments paused? Studies revealed that patients with glioom grade 3 treated with proton therapy had a higher risk of early death compared to those treated with conventional radiation.
• Were patients informed of the risks? No, patients were not informed of the risks until media attention brought the issue to light.

This situation highlights the need for continued vigilance and a commitment to evidence-based medicine. The future of proton therapy hinges on rigorous research, transparent data sharing, and a patient-centered approach that prioritizes safety and informed decision-making.