When Gerrit talks about his melanoma, he speaks with warmth and clarity. It is a story he owns.

“I used to have red hair,” he says matter-of-factly. “That usually comes with very sensitive skin. When you’re young, you don’t always realize the danger of too much sun.”

Years later, the consequences of that sun exposure became clear. He developed melanoma. At one point, his risk of recurrence jumped from five to fifty percent. It was a turning point - not only medically, but personally.

Gerrit was able to participate in an immunotherapy trial in which his own immune cells were trained to recognize melanoma cells. Today, at 71, he has been cancer-free for seven years.

“My survival is partly because of science,” he says. “Becoming a patient partner is my way of giving something back.”

A meeting that mattered

In Utrecht, in the lab of Oncode Investigator Jeroen de Ridder, Oncode Researchers Myrthe and Joske work on artificial intelligence tools to improve cancer diagnostics and treatment decisions. Their days revolve around algorithms, DNA patterns and model performance metrics.

They met Gerrit at an Oncode Patient Perspective Program matchmaking event – in a kind of scientific speed date.

“He stood out immediately,” Myrthe recalls. “He was thoughtful, easy to communicate with, and genuinely interested in understanding what we do.”

Joske laughs. “Very interested. When we tell him what we’ll discuss, he reads up on it beforehand. We sometimes joke he’s not really a layperson anymore.”

“I do my homework,” Gerrit smiles. “If I understand the basics, I can ask better questions.”

"My survival is partly because of science."

Gerrit Oostenveld, Oncode Institute Patient Partner.

From algorithms to people

The lab develops machine-learning models to predict treatment response and prognosis based on tumor DNA and RNA data. They also work on liquid biopsies - blood tests that may one day help detect cancer earlier or monitor treatment in a less invasive way.

It is complex, technical work. Easy, perhaps, to become abstract.

“Explaining our research to Gerrit forces us to zoom out,” Joske says. “In the lab, we focus on details - accuracy numbers, technical problems. But when Gerrit asks, ‘Why does this matter?’, you have to answer differently.”

Myrthe nods. “We work with patient data every day, but in day-to-day analysis you can forget that behind every data point is a person. Talking to Gerrit brings that back to the foreground.”

For Gerrit, those conversations go both ways. He remembers how the researchers once prepared a special presentation to explain their work step by step.

“I appreciated that very much,” he says. “I even told them: you could use this to inspire high school students to choose science.”

When perspective changes the numbers

One discussion in particular left a lasting impression.

The team was debating acceptable error rates in cancer detection - the balance between false positives and false negatives.

“As researchers, we instinctively think false negatives are worst,” Myrthe explains. “You don’t want to miss a patient.”

Gerrit gently challenged that assumption.

“Being told you might have cancer - even if it turns out not to be true - creates enormous stress,” he says. “That’s not just a statistic. That’s sleepless nights.”

He also suggested that acceptable trade-offs might differ by cancer stage. In more aggressive, late-stage disease, speed may matter more than certainty.

“That nuance changed how we think about setting thresholds,” Myrthe reflects. “It reminded us that numbers have emotional weight.”

“Ultimately, we do cancer research for patients. Their perspective isn’t optional. It’s essential.”

Myrthe Jager, Oncode Researcher.

Giving back & moving forward

Gerrit’s involvement is not limited to lab meetings. He prepares for conversations, asks probing questions, and sometimes even writes to politicians about the importance of research funding.

“If many people contribute a little, together it creates a snowball effect,” he says. “You never know the exact impact. But if you do nothing, you know for sure there is none.”

For the researchers, the collaboration is more than symbolic.

“People often say they don’t have time for engaging patients,” Joske says. “But what is two hours every couple of months compared to the value it brings? It sharpens your thinking. It motivates you.”

Myrthe adds, “Ultimately, we do cancer research for patients. Their perspective isn’t optional. It’s essential.”

There is also something harder to quantify - something human.

“Sometimes in life, you meet the right people at the right moment,” Gerrit says. “This is one of those moments. There is mutual respect. Sometimes half a word is enough.”

In a lab filled with data, models and molecular signals, that human connection may be the most powerful outcome of all.

On World Cancer Day, their collaboration is a reminder that progress in cancer research does not happen in isolation. It grows in dialogue - between science and society, between experience and innovation.

The Patient Perspective Programme

Through the Oncode Institute Patient Perspective Programme researchers are stimulated to integrate the perspective of cancer patients into their research. Engaging with cancer patients offers a chance to access first-hand knowledge, and by that, to improve research through novel ideas, perspectives, and discussions. Curious about the ways Oncode Institute involves patients in research? Get into contact with Colette ten Hove.

Photo credits: Rob ter Bekke.