A New Operating System for Cancer: How Sid Sijbrandij is Outpacing an Evolving Disease
What do you do when you’re told: “There’s nothing more we can do”?
That’s the moment Sid Sijbrandij faced after exhausting standard of care for osteosarcoma. Instead of accepting it, he did something radically different. He went “Founder Mode” on his cancer—applying the same mindset he used to build GitLab to create a completely new way of approaching treatment.
What emerged isn’t just a set of therapies. It’s a new operating system for cancer—one built on:
maximal diagnostics
continuous data collection
testing treatments in parallel
and learning faster than the disease evolves
In this episode, we break that system down—not just as Sid’s story, but as a framework patients can start using today.
We cover:
Why he wishes he had focused earlier on tissue preservation and deeper testing
The limitations of how tumors are typically stored (and why it matters)
How cancer can be approached as a dynamic, evolving system
The role of continuous diagnostics, including ctDNA and immune monitoring
Why most patients don’t have a clear therapeutic plan beyond the next step
The real-world challenges of accessing your own tissue and data
Sid also walks through how he began exploring combination and off-label therapies, including immunotherapy approaches designed to increase immune system response.
Sid shares hard-earned insights on:
why preserving tissue and getting the right testing early matters
how to work with (or around) the healthcare system
and why patients may need to drive their own treatment strategy
This conversation is not about doing everything Sid has done. It’s about learning how to think differently—so you can ask better questions, access better options, and make more informed decisions about your care.
Because cancer isn’t one problem. It’s a system. And when you start treating it that way, everything changes.
PATIENT RESOURCE: Sijbrandij Foundation, Future of Cancer Care Today.
A great article about Sid’s Story: https://centuryofbio.com/p/sid
Sid’s personal website with links to all his healthcare information: https://sytse.com/
Even One Ventures (Sid’s Venture Capital company) invests in companies overcoming the barriers of cancer care: https://www.evenone.ventures/
Sid Sijbrandij Bio
Sid Sijbrandij (pronounced ‘see-brandy’) was recently featured in Elliot Hershberg’s article ‘Going Founder Mode on Cancer,’ which highlights how he is applying the same founder mindset he brings to building companies to confronting his osteosarcoma diagnosis.
Sid is the founder of Kilo Code, an open-source AI coding agent, and the co-founder and Board Chair of GitLab Inc., a leading DevSecOps platform that streamlines software delivery, enhances security, and improves compliance for organizations worldwide. Under his leadership, GitLab grew to serve more than 30 million users and has become one of the world’s largest all-remote organizations. Sid was also recognized by Forbes for advocating remote work during the pandemic.
A self-taught Ruby programmer since 2007, Sid discovered GitLab in 2012 and commercialized the project, later leading the company through Y Combinator in 2015.
Earlier in his career, Sid built recreational submarines and developed innovative web applications supporting lawmaking at the Ministerie van Justitie en Veiligheid in the Netherlands. He holds an M.S. in Management Science from the University of Twente.
⏱️ Timestamps
00:00 Episode Intro
02:37 Meet Sid Sijbrandij
09:51 What GitLab Teaches Us About Cancer Care
13:54 The Tissue Hostage Problem
18:39 Building a Therapeutic Ladder
24:11 How AI Empowers Patients
31:36 Future of Cancer Care Today
37:45 Closing Thoughts
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The Outperform Cancer podcast provides health information and should not be viewed as medical, nursing, or other professional healthcare advice. Listening to or engaging with the content does not create a doctor/patient relationship. Some guests are research scientists and biochemists and not medical doctors. Any reliance on the information from this podcast or linked materials is solely at your own discretion. This podcast's content is not meant to replace professional medical guidance, diagnosis, or care. If you have a medical issue or question, consult with a healthcare professional without delay.