# Survival outcomes as time plus event (OS, PFS)

Source: https://onco.cc/terms/os-pfs-time-event/  
OnCo record `os-pfs-time-event` (Term). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

A survival outcome is recorded as two numbers per patient: how long they were followed, and whether the event (death, or progression) happened by then.

## Summary

Survival analysis is the branch of statistics for the expected time until an event such as death occurs (Wikipedia). In datasets such as TCGA the outcome is stored as a time (days to death or to last follow-up) and an event flag (vital status), from which overall survival is computed; progression-free survival needs progression dates, which TCGA records unevenly. Follow-up in TCGA is short for many cancers, so event counts are low and survival models trained on it are noisy.

## Fields

- Kind: Term
- Last checked: 2026-09-24
- Also known as: time-to-event outcome; time and event; survival time and status; OS time; PFS time; event indicator; vital status; days to death; days to last follow-up
- Tags: cansim-terms

## Notes

- Listed in the CanSim terms map 1.0.0 (docs/onco/terms.json, generated 2026-09-24), CC BY 4.0, attribution: CanSim project, an open, public-data-first cancer foundation-model programme; CanSim page path /terms/os-pfs-outcomes.

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Survival_analysis
- Wikipedia: https://en.wikipedia.org/wiki/Survival_analysis

## Connected records

- terms: [Cancer AI vocabulary (CanSim terms map)](https://onco.cc/terms/cancer-ai-vocabulary/), [Censoring and events in survival data](https://onco.cc/terms/censoring-and-events/), [Kaplan-Meier curve, censoring and proportional hazards](https://onco.cc/terms/kaplan-meier-curve/), [Overall survival (OS)](https://onco.cc/terms/os/), [Progression-free survival (PFS)](https://onco.cc/terms/pfs/)

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JSON: https://onco.cc/api/v1/entities/os-pfs-time-event.json