# Sid Sijbrandij

Source: https://onco.cc/people/sid-sijbrandij/  
OnCo record `sid-sijbrandij` (Person). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

The GitLab co-founder who kept working and writing in public through osteosarcoma treatment, showing what living with a rare bone cancer looks like from the inside.

## Summary

Sid Sijbrandij co-founded GitLab, the software development platform, and led it as chief executive until stepping back to chair the board. In 2023 he was diagnosed with osteosarcoma, a rare bone cancer, and chose to describe the diagnosis, chemotherapy and its side effects in public posts rather than step out of view. His account is the kind OnCo exists to connect: a working adult with a rare cancer, treated with the same chemotherapy backbone used for children, explaining decisions as they were made. The record links to his own posts and to the GitLab announcement of his change of role.

## Fields

- Kind: Person
- Last checked: 2026-09-09
- Tags: hero; patient; technology
- Role: GitLab co-founder living with osteosarcoma; writes openly about treatment and work
- Specialisms: Living with cancer; Rare cancers; Patient voice

## Sources

- Sid Sijbrandij on X: https://x.com/sytses

## Connected records

- cancers: [Osteosarcoma](https://onco.cc/cancers/osteosarcoma/), [Sarcomas (soft tissue, bone, GIST)](https://onco.cc/cancers/sarcoma/)
- companies: [Even One Ventures](https://onco.cc/companies/evenone-ventures/), [Future of Cancer Care Today (FCCT)](https://onco.cc/companies/future-of-cancer-care-today/), [Sijbrandij Foundation](https://onco.cc/companies/sijbrandij-foundation/)

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JSON: https://onco.cc/api/v1/entities/sid-sijbrandij.json