Founder Mode on Cancer: Sid Sijbrandij's approach to beating osteosarcoma

Sid Sijbrandij, co-founder and CEO of GitLab, was diagnosed with high-grade osteosarcoma in late 2022. After standard treatment (surgery, radiation, chemo) and two years of remission, the cancer progressed in 2024. Doctors told him “standard of care is done.”

Instead of accepting that, he went “founder mode” — applying the same startup mindset that built GitLab to fighting his cancer:

• Maximal Diagnostics: Going beyond standard tests to understand his specific tumor
• Personalized Drugs: Creating 10+ custom treatments including mRNA vaccines, TCR-T, CAR-T, and antibody-drug conjugates
• Parallel Treatments: Running multiple approaches simultaneously instead of sequential trial-and-error
• Scaling for Others: Founded ~10 companies to make these treatments accessible

He published 25TB of his cancer data openly, proposed 14 policy reforms for patient-first treatment access, and now has ~30 treatments on his “therapeutic ladder” — from zero after standard care ended.

The insight: The same skills that make someone a great founder — relentless problem-solving, parallel execution, data-driven decisions, building systems that scale — can be applied to seemingly unsolvable personal challenges. Also a stark reminder of how much the current medical system leaves on the table for motivated patients.